| Main Search Form | List of XMM-NEWTON Catalogs |
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| Main Search Form | List of XMM-NEWTON Catalogs |
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The authors of this catalog conclude that their findings are best interpreted in a context where radio emission in AGN, with the exception of a minority of beamed sources, arises from very close to the accretion disk and is therefore heavily linked to X-ray emission. They also speculate that the radio-loud/radio-quiet dichotomy might either be an evolutionary effect that developed well after the QSO peak epoch, or an effect of incompleteness in small samples.
Basic information and derived properties are presented for the sample of X-ray selected type 1 AGN (as well as for the 11 X-ray undetected type 1 AGN in the "control sample"): coordinates, redshift, X-ray and radio fluxes, optical magnitudes, from the SDSS, 2XMMi, and FIRST catalogs; continuum luminosities at 3000 Angstroms and in the X-ray band, black hole masses, bolometric luminosities, Eddington ratios; for the sources falling in the FIRST field, optical fluxes at 2500 and 4400 Angstroms, X-ray-to-optical index, radio classification, and the ratios between the radio and the UV, optical, and X-ray fluxes.
This table contains the subset of 153 brighter hard X-ray sources in the XMM-Newton/Sloan Digital Sky Survey (SDSS) sample which have 2-8 keV fluxes > 3 x 10-14 erg cm-2 s-1, excluding a number of sources with extended optical morphology and blue colors, as well as 4 sources with X-ray to optical fluxes < 0.1 which are fit better with stellar rather than QSO templates.
Much more information on the SDSS is available at the project's web site at http://www.sdss.org/.
Alpha Per is a young open cluster, found to be 50 Myr old from its upper main sequence turnoff morphology (Meynet et al. 1993, A&AS, 98, 477). More recently, Stauffer et al. (1999, ApJ, 527, 219) have found an age of 90 Myr from the low mass lithium depletion boundary. In addition to being relatively nearby (170 pc; Randich et al. 1996, A&A, 305, 785), the Alpha Per cluster is also lightly reddened (E(B - V ) = 0.09 mag; Meynet et al. 1993), making the data interpretation relatively robust.
A fraction of the Alpha Per cluster was observed by XMM-Newton as part of the Mission Scientist Guaranteed Time (Pallavicini et al., 2004, MmSAI, 75, 434). A 60-ks observation was obtained on 2000 September 5 using the EPIC MOS and PN cameras on board XMM-Newton with a pointing centered at RA: 3h 26m 16s and Dec: 48o 50m 29s (J2000.0).
The AXIS source counts results are compatible with most previous samples in the soft, XID, ultra-hard and hard bands. This study has improved on previous results in the hard band. The fractions of the XRB resolved in the surveys used in this work are 87%, 85%, 60% and 25% in the soft, hard, XID and ultra-hard bands, respectively. Extrapolation of the source counts to zero flux is not sufficient to saturate the XRB intensity. Only galaxies and/or absorbed AGN could contribute the remaining unresolved XRB intensity. These results are compatible, within the errors, with recent revisions of the XRB intensity in the soft and hard bands. The maximum fractional contribution to the XRB comes from fluxes within about a decade of the break in the source counts (~10-14 cgs), reaching ~50% of the total in the soft and hard bands. Angular clustering (widely distributed over the sky and not confined to a few deep fields) is detected at 99-99.9% significance in the soft and XID bands, with no detection in the hard and ultra-hard band (probably due to the smaller number of sources). The authors cannot confirm the detection of significantly stronger clustering in the hard-spectrum hard sources. Medium-depth surveys such as AXIS are essential to determine the evolution of the X-ray emission in the Universe below 10 keV.
Included here are the basic data for the 2560 X-ray sources in the reference paper which satified the selection criteria of having an emldetect detection likelihood >= 10 (the default value) in at least one band, namely:
(i) XMM-Newton pn count-rates in four XMM-Newton Science Analysis System (SAS) bands (band 2: 0.5 - 2 keV, band 3: 2 - 4.5 keV, band 4: 4.5 - 7.5 keV, band 5: 7.5 - 12 keV); (ii) spectral photon indices in the 0.5 - 4.5 keV band, the 2 - 10 keV band and the 0.5 - 10 keV band; (iii) fluxes in the soft (0.5 - 2 keV), hard (2 - 10 keV), XID (0.5 - 4.5 keV), ultra-hard (4.5 - 7.5 keV) and "total" (0.5 - 10 keV) bands; and (iv) flags describing to which of the samples discussed in the paper (soft, hard, XID or ultra-hard) each source belongs.
There is no spectral or flux information given for the sources not belonging to any of the samples, but the count-rates of such sources are given for completeness.
The authors performed source detection on all the XMM-Newton data in two energy bands: 0.2 - 1 keV ("soft") and 1 - 10 keV ("hard"). They detected 24 soft sources and 85 hard sources. Seven of the sources appear in both bands, where the criterion for a match between the bands is a positional offset of < 2.5 arcseconds. Thus, the total number of distinct X-ray sources detected (and listed in this table) is 102.
The authors compare their results with the predictions of three semi-analytic models based on the Millennium simulation. The intercept of the relation between the magnitude of the brightest galaxy and the value of magnitude gap becomes brighter with increasing redshift. This trend is steeper than the model predictions which the authors attribute to the younger stellar age of the observed brightest cluster galaxies. This trend argues in favor of stronger evolution of the feedback from active galactic nuclei at z < 1 compared to the models. The slope of the relation between the magnitude of the brightest cluster galaxy and the value of the gap does not evolve with redshift and is well reproduced by the models, indicating that the tidal galaxy stripping, put forward as an explanation of the occurrence of the magnitude gap, is both a dominant mechanism and sufficiently well modeled.
In this study, the authors analyzed the XMM-Newton observations of the CFHTLS wide (W1) field as a part of the XMM-LSS survey (Pierre et al., 2007, MNRAS, 382, 279). The details of the observations and the data reduction are presented in Bielby et al. (2010, A&A, 523, A66). The authors concentrate on the low-z counterparts of the X-ray sources and use all XMM-Newton observations performed until 2009, covering an area of 2.276 x 2.276 square degrees. The CFHTLS wide observations were carried out in the period between 2003 and 2008, covering an effective survey area of ~ 154 square degrees. The optical images and data of the CFHTLS were obtained with the MegaPrime instrument mounted on the CFHT in the five filters u*, g', r', i' and z'.
The observations performed with XMM-Newton resulted in a sample of 387 X-ray sources (187, 84, 37, and 79 in Fields E, C, S , and W, respectively), 340 of which have one or more NIR (2MASS) counterparts. This table contains the 2MASS photometry, estimates of age and mass, and infrared classification of members of the CMa R1 region and counterparts to X-ray sources, based on 2MASS and WISE data. The authors also used X-ray data to characterize the detected sources (387 sources) according to hardness ratios, light curves, and spectra (see the associated table CMAOB1XMM).
For this work, four fields (each about 30-arcmin diameter with some overlap) were defined. These fields are located inside the arc-shaped ionized nebula, next to Z CMa - Field E (east); around GU CMa - Field W (west); and between both - Field C (center) and Field S (south), as shown in Figure 1 of the reference paper.
RA(J2000) | Dec(J2000) | Designation(s) 07 04 18.3 | -11 27 24.0 | CMa cluster east (Field E) 07 02 58.4 | -11 34 44.7 | CMa cluster center (Field C) 07 02 29.5 | -11 47 12.4 | CMa cluster south (Field S) 07 01 23.0 | -11 19 56.6 | CMa cluster west (Field W)
The authors have selected NIR counterparts by searching the 2MASS catalog for candidates located less that 10'' away from the nominal X-ray source positions. No counterpart was found for 45 sources. Candidates for which the distance seems to be incompatible with the CMaR1 molecular cloud were disregarded. This table includes the complete list of NIR counterparts, however the authors only consider as reliable those flagged as 'AAA' in the 2MASS catalog (i.e., with S/N > 10, magnitude errors <0.1 mag, and above the JHK completeness limits), given by the twomass_flags field in this table. There are 340 such reliable NIR counterparts for 290 X-ray sources, including 46 X-ray sources with multiple counterpart candidates.
X-ray and NIR data have revealed that most (79%) of the XMM-Newton sources are probable members of CMa R1. The combination of the results from both analyses can confirm their young nature. On the other hand, 21% of the XMM-Newton sample are probably field objects. Among these, 6% (23/387) have infrared counterparts that probably are foreground stars and 4% (17/387) have counterparts that are too faint (bad quality data) without reliable classification. The other 11% of undefined sources (44/387) do not have 2MASS data because they are classified as possible background objects. The authors have seen that the XMM-Newton error boxes may include multiple NIR counterparts. In such cases, they restricted the comparative analysis to the 158 X-ray sources of their "best sample" that are associated with a single NIR counterpart, as described in Section 4.3 of the reference paper.
A distance of 1 kpc to CMa OB1 is assumed for this table.
The authors used X-ray data to characterize the detected sources according to hardness ratios, light curves, and spectra. They also provided estimates of mass and age, using the information from likely counterparts based on the 2MASS catalogue. The 2MASS-derived data on the counterparts, where matched, are provided in the associated table (CMAOB1NIR).
This table contains a catalog of 387 XMM-Newton sources, of which 78% are confirmed as members or probable members of the CMa R1 association. Flares (or similar events) were observed for 13 sources and the spectra of 21 bright sources could be fitted by a thermal plasma model. Mean values of fits parameters were used to estimate X-ray luminosities.
The authors found a minimum value of log(LX [erg/s]) = 29.43, indicating that the sample of low-mass stars (M* <= 0.5 Msun), which are faint X-ray emitters, is incomplete. Among the 250 objects selected as the complete subsample (defining a "best sample"), 171 are found to the east of the cloud, near Z CMa and dense molecular gas, of which 50% of them are young (<5Myr) and 30% are older (>10Myr). The opposite happens to the west, near GU CMa, in areas lacking molecular gas: among 79 objects, 30% are young and 50% are older. These findings confirm that a first episode of distributed star formation occurred in the whole studied region ~10Myr ago and dispersed the molecular gas, while a second, localized episode (<5Myr) took place in the regions where molecular gas is still present.
For this work, four fields (each about 30-arcmin diameter with some overlap) were observed with the XMM-Newton satellite. These fields are located inside the arc-shaped ionized nebula, next to Z CMa - Field E (east); around GU CMa - Field W (west); and between both - Field C (center) and Field S (south), as shown in Figure 1 of the reference paper.
These observations were performed with the EPIC cameras (MOS1, MOS2, and PN) in full frame mode with a medium filter. The C, W, and S fields had an exposure time without background corrections of about 30 ks while field E had 40 ks.
RA(J2000) | Dec(J2000) | Designation(s) 07 04 18.3 | -11 27 24.0 | CMa cluster east (Field E) 07 02 58.4 | -11 34 44.7 | CMa cluster center (Field C) 07 02 29.5 | -11 47 12.4 | CMa cluster south (Field S) 07 01 23.0 | -11 19 56.6 | CMa cluster west (Field W)
The authors have combined two exposures taken with the XMM-Newton satellite with an exhaustive data set of optical, near- and mid-infrared photometry to assess the membership of the X-ray sources based on different color-color and color-magnitude diagrams, as well as other properties, such as effective temperatures, masses and bolometric luminosities derived from spectral energy distribution fitting and comparison with theoretical isochrones. The presence of circumstellar disks is discussed using mid-infrared photometry from the Spitzer Space Telescope.
The authors searched for optical and IR counterparts for their X-ray detections, using a radius of 5.1 arcseconds. This search radius is motivated by the astrometry of XMM-Newton (~ 1-2 arcsec) and the statistical errors of the X-ray sources (<= 4 arcsecs). Multiple counterparts were found for several X-ray sources within their search radius. The visual inspection of all optical and IR images indicated that in a few cases there were additional possible counterparts even slightly beyond this search radius. In order to be as comprehensive as possible, the authors have also retained them. They compiled a master catalog with all sources that were present in at least one of the mappings (optical, near-IR or mid-IR) and extracted the photometry from these surveys. The photometry of all possible counterparts to X-ray sources is listed in this table.
The reference sources for the optical and infrared magnitudes are discussed in Section 3 of the reference paper. In this table, they are coded as follows:
Code Reference Source 1 = 2MASS Catalog, CDS Cat. II/246 2 = XMM-Newton Optical Monitor (XMM OM) 3 = Spitzer 4 = Omega 2000 Camera photometry in 2005 5 = CFHT1999 Survey 6 = Barrado y Navascues et al. (2004 ApJ, 610, 1064; 2007 ApJ, 664, 481) 7 = Dolan & Mathieu (1999 AJ, 118, 2409; 2001 AJ, 121, 2124) 8 = Dolan & Mathieu (2002 AJ, 123, 387) 9 = Omega 2000 Camera photometry in 2007Thus, this table contains optical and infrared data, as well as membership information, on 205 possible counterparts to the 164 XMM-Newton X-ray sources detected in EPIC observations of the Collinder 69, East and West Fields (C69E and C69W), respectively, with maximum likelihood (ML) values > 15.0. A companion HEASARC Browse table COLL69XMM contains the X-ray data for these X-ray sources.
The authors have combined two exposures taken with the XMM-Newton satellite with an exhaustive data set of optical, near- and mid-infrared photometry to assess the membership of the X-ray sources based on different color-color and color-magnitude diagrams, as well as other properties, such as effective temperatures, masses and bolometric luminosities derived from spectral energy distribution fitting and comparison with theoretical isochrones. The presence of circumstellar disks is discussed using mid-infrared photometry from the Spitzer Space Telescope.
This table contains the XMM-Newton X-ray point source catalog for all sources detected in the EPIC observations of the Collinder 69, East and West Fields (C69E and C69W), respectively, with maximum likelihood (ML) values > 15.0. A companion HEASARC Browse table COLL69OID contains optical and infrared data as well as membership information on counterparts to these X-ray sources.
This table summarizes the multiwavelength properties of the 692 AGN-host systems detected in the COSMOS field both in the X-ray and in the FIR (the X-FIR sample).
Six XMM-Newton observations of the core of Cyg OB2 were obtained. In the analysis, the author paid particular attention to the variability of the X-ray bright OB stars, especially the luminous blue variable candidate Cyg OB2 #12. He found that X-ray variability is quite common among the stars in Cyg OB2. While short-term variations are restricted mostly to low-mass pre-main sequence stars, one third of the OB stars display long-term variations. The X-ray flux of CygO B2 #12 varies by 37%, over timescales from days to years, while its mean log LX/Lbol amounts to -6.10. These properties suggest that Cyg OB2 wind. Two other X-ray bright O-type stars (MT91 516 and CPR2002A11) display variations that suggest they are interacting wind binary systems.
This table lists the general properties of the X-ray sources detected in Cyg OB2 with the EPIC cameras onboard XMM-Newton as given in Table 2 of the reference paper. An additional list of the properties of the sources detected inside Cyg OB2 with the two UV filters of the OM instrument onboard XMM-Newton which was contained in Table 4 of the reference paper is not included herein.
The authors classified 47% of the sources with spectroscopic redshift as broad-line active galactic nuclei (BL AGNs) with z = 0.1-3.5, while sources without broad-lines (NOT BL AGNs) are about 46% of the spectroscopic sample and are found up to z = 2.6. The remaining fraction is represented by extended X-ray sources and stars. The authors spectroscopically identified 11 type 2 QSOs among the sources with F(2-10 keV)/F(R) > 8, with redshift between 0.9 and 2.6, high 2-10 keV luminosity (log L(2-10 keV) >= 43.8 erg/s) and hard X-ray colors suggesting large absorbing columns at the rest frame (log NH up to 23.6 cm-2). BL AGNs show on average blue optical-to-near-infrared colors, softer X-ray colors and X-ray-to-optical colors typical of optically selected AGNs. Conversely, narrow-line sources show redder optical colors, harder X-ray flux ratio and span a wider range of X-ray-to-optical colors. On average the Spectral Energy Distributions (SEDs) of high-luminosity BL AGNs resemble the power-law typical of unobscured AGNs. The SEDs of NOT BLAGNs are dominated by the galaxy emission in the optical/near-infrared, and show a rise in the mid-infrared which suggests the presence of an obscured active nucleus. The authors have used the infrared-to-optical colors and near-infrared SEDs to infer the properties of the AGN host galaxies.
Identifications and photometric parameters for 478 sources detected by XMM-Newton in the ELAIS-S1 field are given. For each source, the X-ray positions and fluxes, optical position and photometry, Spitzer IRAC and MIPS 24 micron positions and fluxes, spectroscopic redshift where available, photometric redshift and SED shape classification are given.
The mosaic of four partially overlapping deep XMM-Newton pointings covers a large (~0.6 deg2) and contiguous area of the ELAIS-S1 region. The pointings are named
ELAIS-S1-A (RA=8.91912, DE=-43.31344, J2000),
ELAIS-S1-B (RA=8.92154, DE=-43.65575, J2000),
ELAIS-S1-C (RA=8.42195, DE=-43.30488, J2000) and
ELAIS-S1-D (RA=8.42375, DE=-43.65327, J2000).
The X-ray observations were performed on May 2003 through July 2003
with XMM-Newton's European Photon Imaging Camera (EPIC) and two MOS-CCD
cameras.
This table contains the X-ray and optical information for the sources detected in the sum of 3 separate XMM-Newton observations of a field centered on 14 49 25, +09 00 13 (J2000.0 RA and Dec) known as the "Daddi" field (Daddi et al. 2000, A&A, 361, 535) in which 257 EROs are known to be present. The data from all 3 EPIC instruments (PN, MOS1 and MOS2) obtained in the 3 observations was combined, yielding a total exposure time for the PN of ~82 ks, and for the MOS instruments of ~78 ks. The X-ray hardness ratio (HR) and the optical to near-infrared color (R and K magnitudes) are reported for all the detected X-ray sources and their counterparts, along with the reliability of the X-ray to optical or near-infrared associations as measured by the likelihood ratios, LR(R) and LR(K). This table lists data for the 111 proposed optical/infrared counterparts for the 97 detected X-ray sources, i.e., X-ray sources with more than one possible optical/IR counterpart will have multiple entries in this table, one for each counterpart, as follows: 73 X-ray sources have secure optical/near-IR counterparts (counterpart_status=1), 7 X-ray sources have 2 possible 'likely' counterparts, and 1 X-ray source has 3 such counterparts (counterpart_status=2), 6 X-ray sources have only low-likelihood counterparts all of which lie outside the 3" matching radii (counterpart_status=3), and the remaining 9 X-ray sources lack optical and infrared photometry (counterpart_status=4).
The XMM-Newton observations were taken on 2003 July 3 with a total exposure time of ~45 ks for the EPIC-MOS cameras and ~42 ks for the European Photon Imaging Camera (EPIC) PN camera. The authors use only the data from the PN camera (with a thin optical blocking filter) because of its high sensitivity to soft X-rays in the study of diffuse emission and include the data from the MOS cameras in the analysis of X-1. The Chandra observation, taken on 2003 March 12 with an exposure of 29 ks and already described by Bauer and Brandt (2004, ApJ, 601, 67), was reprocessed by the authors using the then-latest CIAO software (version 3.2.1) and calibration database (version 3.0.0).
The authors used the Two-Micron All Sky Survey (2MASS) All-Sky Catalog of Point Sources (Cutri et al. 2003 CDS Catalog II/246) to search for potential counterparts. They cross-correlated the spatial positions of the objects in this catalog with their X-ray source positions, using a matching radius of 4 arcsec for XMM-Newton PN sources and 2 arcsec for Chandra ACIS sources. The radius was chosen to be greater than the 1-sigma statistical position uncertainty of almost all the sources.In no case is there a match with multiple 2MASS objects. The 3-sigma limiting sensitivities of the 2MASS Catalog are 17.1, 16.4 and 15.3 mag in the three bands, J, H, and KS, respectively.
The authors have observed IC 1805 with XMM-Newton and further collected optical spectroscopy of some of the O-star members of the cluster. The optical spectra allowed them to revisit the orbital solutions of BD +60 497 and HD 15558, and provided the first evidence of binarity for BD +60 498. X-ray emission from colliding winds does not appear to play an important role among the O-stars of IC 1805. Notably, the X-ray fluxes do not vary significantly between archival X-ray observations and the present XMM-Newton pointing. The very fast rotator BD +60 513, and to a lesser extent the O4 If+ star HD 15570, appear somewhat underluminous. While the underluminosity of HD 15570 is only marginally significant, its amplitude is found to be compatible with theoretical expectations based on its stellar and wind properties. A number of other X-ray sources are detected in the field, and the brightest objects, many of which are likely low-mass pre-main sequence stars, are analyzed in detail.
This table provides the full catalog of the 191 X-ray sources detected with the EPIC detectors onboard XMM-Newton in the direction of the IC 1805 cluster. The coordinates of the sources were cross-correlated with the optical and IR catalogs of Straizys et al. (2013, A&A, 554, A3), Wolff et al. (2011, ApJ, 726, 19), and the SIMBAD database. The authors adopted in each case a correlation radius of 4 arcseconds.
This tables provides the list of 368 detected X-ray sources in/toward the Cen OB2 association cluster(s) IC 2944/2948 only, i.e., the 58 X-ray sources detected in/toward the HM1 cluster are not contained herein. This tables lists the basic X-ray source properties (position, count rates, hardness ratios) and their probable optical/infrared counterparts (offset angular distance, name).
XMM-Newton has observed IC 2944/2948 for 40 ks on XMM-Newton Rev. 2209 (with the THICK filter). No background flare affected the observation, and no source is bright enough to suffer from pile-up.
The XMM-Newton observations consist of two fields, north (Field N = KN) and south (Field S = KS), and were obtained in 2015 March 10 and 15 using EPIC as the primary instrument. Table 1 in the reference paper shows the details of the exposures, each one with a duration of about 50 ks and taken with the Medium filter. The authors used SAS version 14.0 to reduce the observation data files (ODFs) and to obtain calibrated lists of events for the MOS and pn instruments. They filtered the events in the 0.3-0.8 keV energy band and used only events with FLAG = 0 and PATTERN < 12 as prescribed by the SAS manual. With SAS, the authors obtained exposure maps in the 0.3-8.0 keV band and performed source detection with a code based on wavelet convolution that operated simultaneously on MOS and pn data. They used a threshold of significance of 4.5 sigma of the local background to discriminate real sources from spurious background fluctuations. However, they added few sources to the final list with significance S in 4.0 < S < 4.5 for the cases of positional match with objects in SIMBAD or PPMX catalogs. The final list was also checked for spurious sources that could appear at the border of the CCDs. In sum, the authors detected 238 X-ray sources with significance > 4 sigma of the local background; 104 sources are in KN and 134 in KS.
The authors cross-correlated the positions of the X-ray sources with the coordinates of the IR catalog of Megeath et al. (2012, AJ, 144, 192). This IR catalog is the result of a survey of Orion with Spitzer that produced a classification of protostars and stars with disks. Of the 238 X-ray sources, 191 are identified within 8 arcseconds of one of 206 IR objects, 99 sources in KS, 92 sources in KN. Some X-ray sources were multiple matches within 8 arcsec of IR objects. For these cases, the authors assigned the most likely counterparts based on IR photometry and visual inspection of X-rays and IR images. However, nine X-ray sources were left associated with two or three IR objects. Among the IR matches, the authors found 15 stars with disks in KN and 35 in KS with X-ray detection. One protostar in KN and three in KS were detected in X-rays.
The authors used X-ray detection of sources without IR excess as criteria to identify disk-less stars (hereafter Class III stars). They classified as Class III stars those IR objects with X-ray detections, with [4.5um]-[8.0um] colors < 0.3 mag and brighter than [4.5um] magnitude < 14. At the distance of the ONC (400 pc), the [4.5um] magnitude ~ 14 threshold at an age of 4-5 Myrs roughly identifies M3-M4 spectral types and masses around 0.3 solar masses. With this selection scheme, the authors identified 48 objects in KN and 19 in KS as Class III candidates.
The SOXS survey is composed of seven specifically proposed ~ 50 ks XMM-Newton fields, south of the ONC, to which the authors added four archival fields in the same region. The archival fields are centered on iota Orionis, V380 Ori, and V883 Ori, respectively (see Fig. 1 and Table 1 of the reference paper for more details of the X-ray observations).
This HEASARC table contains the contents of Table 2 (1060 X-ray detected sources in the fields S1 - S10 listed in Table 1 of the reference paper), Table 3 (best-fit spectral parameters for the 232 brightest of these X-ray sources) and Table 4 (list of 1041 IR counterparts to the X-ray sources) from the reference paper. Some X-ray sources have no identified counterparts (16 of them in fact lie outside of the FOV of the Spitzer observations), most have a single counterpart, and a small number have 2 or even 3 IR counterparts within the 5 arcseconds matching radius used. For X-ray sources with more than 1 IR counterpart, we have added entries for the additional counterparts (71 in total), repeating the X-ray information in such cases. Thus, this HEASARC table contains 1131 (1060 + 71) entries corresponding to the 1060 X-ray source detections. To make its contents easier to visualize, the HEASARC has added a a parameter ir_match which lists the counterpart number for the entry: If there is no identified IR counterpart, ir_match is set to 0, for the first listed IR counterpart to 1, for the second and third, to 2 and 3, respectively. Thus, if the user wants to reduce the table back to a pure list of X-ray sources and their primary IR counterparts, they should search the table selecting ir_match < 2.
The authors detected 167 X-ray sources above a 5-sigma detection threshold the properties of which are listed in this table, of which 58 are identified with known cluster members and candidates, from massive stars down to low-mass stars with spectral types of ~ M5.5. Another 23 sources were identified with new possible photometric candidates. Late-type stars have a median log LX/Lbol ~ -3.3, close to the saturation limit. Variability was observed in ~ 35% of late-type members or candidates, including six flaring sources. The emission from the central hot star Lambda Ori is dominated by plasma at 0.2 - 0.3 keV, with a weaker component at 0.7 keV, consistent with a wind origin. The coronae of late-type stars can be described by two plasma components with temperatures T1 ~ 0.3-0.8 keV and T2 ~ 0.8-3 keV, and subsolar abundances Z ~ 0.1-0.3 Zsun, similar to what is found in other star-forming regions and associations. No significant difference was observed between stars with and without circumstellar discs, although the smallness of the sample of stars with discs and accretion does not definitive conclusions to be drawn. The authors concluded that the X-ray properties of Lambda Ori late-type stars are comparable to those of the coeval Sigma Ori cluster, suggesting that stellar activity in Lambda Ori has not been significantly affected by the different ambient environment.
The lambda Ori cluster was observed by XMM-Newton from 20:46 UT on September 28, 2006 to 12:23 UT on September 29, 2006 (Obs. ID 0402050101), for a total duration of 56ks, using both the EPIC MOS and PN cameras and the RGS instruments. The EPIC cameras were operated in full frame mode with the thick filter.
The X-ray observations of the Lockman Hole took place between April 2000 and December 2002 with XMM-Newton. The optical observations of the Lockman Hole were conducted with the Large Binocular Telescope (U, B, V bands) and the Subaru Telescope (RC, IC, z' bands). The LBT observations were taken from February 2007 to March 2009. The RC, IC, and z' bands have been observed with the Suprime-Cam of the Subaru telescope between November 2001 and April 2002.
This table contains the properties of the counterparts to all 409 X-ray sources listed in the Lockman Hole XMM-Newton source catalog of Brunner et al. (2008, A&A, 479, 283), including the 377 AGN and also the 32 objects classified as Galactic stars, galaxy clusters or galaxies. For 8 (2%) of the 409 X-ray sources no optical or IR counterparts were found. These 8 objects are listed in this table with null positional values.
While the spectral and timing properties of the brightest sources were presented by Jenkins et al. (2004, MNRAS, 349, 404: Paper I), in the present analysis the authors apply an X-ray colour classification scheme to split the entire source population into different types, i.e. X-ray binaries (XRBs), SNRs, absorbed sources, background sources and supersoft sources (SSSs). Approximately 60% of the population can be classified as XRBs, although there is source contamination from background active galactic nuclei (AGN) in this category as they have similar spectral shapes in the X-ray regime. 15 sources have X-ray colours consistent with SNRs, three of which correlate with known SNR/HII radio sources. Another two are promising new candidates for SNRs, one is unidentified, and the remainder are a mixture of foreground stars, bright soft XRBs and AGN candidates. The authors also detect 14 candidate SSSs, with significant detections in the softest X-ray band (0.3 - 1 keV) only. 16 sources display short-term variability during the XMM-Newton observation, twelve of which fall into the XRB category, giving additional evidence of their accreting nature. Using archival Chandra and ROSAT High Resolution Imager data, the authors find that ~40% of the XMM sources show long-term variability over a baseline of up to ~10 yr, and eight sources display potential transient behaviour between observations. Sources with significant flux variations between the XMM and Chandra observations show a mixture of softening and hardening with increasing luminosity. The spectral and timing properties of the sources coincident with M 101 confirm that its X-ray source population is dominated by accreting XRBs.
The authors cross-correlated the XMM-Newton source list with previous X-ray observations of M 101. For the Chandra observations detailed in Section 2 of the reference paper, they matched on-axis sources (whose positions are generally accurate to ~1 arcsec) to within the XMM-Newton 3-sigma errors. For off-axis sources, the decreasing Chandra positional accuracy to ~2 arcsec was also taken into account. However, given the large PSF of XMM-Newton (~6 arcsec FWHM), they also checked for any contamination from additional fainter sources detected only by Chandra by searching for sources that lie within 15 arcsec of the XMM-Newton source positions (this corresponds to the on-axis 68% energy cut-out radius used in emldetect). In total, 71 XMM-Newton sources were unambiguously matched to single Chandra sources within the 3-sigma errors, whereas the nuclear source is resolved into two sources by Chandra. These matches are listed in this table, as are additional sources matching to within 15 arcsec. For completeness, both the CXOU designations of Kilgard et al. (2005, ApJS, 159, 214) and equivalent source source numbers from Pence et al. (2001, ApJ, 561, 189) are given.
M 101 was observed with XMM-Newton for 42.8 ks on 2002 June 4 (Obs ID 0104260101). The EPIC MOS-1, MOS-2 and PN cameras were operated with medium filters in the 'Prime Full Window' mode, which utilizes the full ~ 30-arcmin field of view of XMM-Newton, covering the entire D25 ellipse of M101.
An X-ray catalog of 1897 sources was created ('the XMM LP-total catalog'), with 914 sources detected for the first time. Source classification and identification were based on X-ray hardness ratios, spatial extents of the sources, and cross correlation with catalogs in the X-ray, optical, infrared and radio wavelengths. The authors also analysed the long-term variability of the X-ray sources and this variability allowed them to distinguish between X-ray binaries and active galactic nuclei (AGN). Furthermore, supernova remnant classifications of previous studies that did not use long-term variability as a classification criterion could be validated. Including previous Chandra and ROSAT observations in the long-term variability study allowed the authors to detect additional transient or at least highly variable sources, which are good candidate X-ray binaries.
Fourteen of the 30 supersoft source (SSS) candidates represent supersoft emission of optical novae. Many of the 25 supernova remnants (SNRs) and 31 SNR candidates lie within the 10 kpc dust ring and other star-forming regions in M 31. This connection between SNRs and star-forming regions implies that most of the remnants originate in type II supernovae. The brightest sources in X-rays in M 31 belong to the class of X-ray binaries (XRBs). Ten low-mass XRBs (LMXBs) and 26 LMXB candidates were identified based on their temporal variability. In addition, 36 LMXBs and 17 LMXB candidates were identified owing to correlations with globular clusters and globular cluster candidates. From optical and X-ray colour-colour diagrams, possible high-mass XRB (HMXB) candidates were selected. Two of these candidates have an X-ray spectrum as expected for an HMXB containing a neutron star primary.
While this survey has greatly improved our understanding of the X-ray source populations in M 31, at this point 65% of the sources can still only be classified as "hard" sources; i.e. it is not possible to decide whether these sources are X-ray binaries or Crab-like supernova remnants in M 31 or X-ray sources in the background. Deeper observations in X-ray and at other wavelengths would help to classify these sources.
One observation of each disc field of M 31 was taken using the EPIC pn and MOS cameras on XMM-Newton in January and June 2002. The authors obtained background-subtracted spectra and lightcurves for each of the 335 X-ray point sources detected across the five observations from 2002. They also correlate their source list with those of earlier X-ray surveys and radio, optical and infra-red catalogs. Sources with more than 50 source counts are individually spectrally fit in order to create the most accurate luminosity functions of M 31 to date.
Based on the spectral fitting of these sources with a power law model, the authors observe a broad range of best-fit photon index. From this distribution of best-fit index, they identify 16 strong high mass X-ray binary system candidates in M 31. They show the first cumulative luminosity functions created using the best-fit spectral model to each source with more than 50 source counts in the disc of M 31. The cumulative luminosity functions show a distinct flattening in the X-ray luminosity LX interval 37.0 <~ log LX erg s-1 <~ 37.5. Such a feature may also be present in the X-ray populations of several other galaxies, but at a much lower statistical significance. The authors investigate the number of AGN present in their source list and find that, above LX ~1.4 x 1036 erg s-1, the observed population is statistically dominated by the point source population of M 31.
In a second paper, the authors presented an extension to the original 2005 XMM-Newton X-ray source catalog of M 31 which contained 39 newly found sources. These sources have been added to the original 856 sources to make a combined catalog of 895 X-ray sources which is contained herein.
The list of XMM-Newton observations used for this survey is given in Table 1 of the reference paper. The data reduction and source detection techniques are described in Section 3 of this same reference.
The unabsorbed energy conversion factors (ECF) values for different energy bands and instruments that were used in this paper are as follows (the units are 1011 counts cm2 erg-1):
HEASARC Energy Band MOS1 MOS2 PN band prefix (keV) Med Filter Med Filter Thin Filter sb0_ 0.2-0.5 0.5009 0.4974 2.7709 sb1_ 0.5-1.0 1.2736 1.2808 6.006 mb_ 1.0-2.0 1.8664 1.8681 5.4819 hb_ 2.0-4.5 0.7266 0.7307 1.9276 fb_ 0.2-4.5
This catalog utilized data from a deep survey of M 33 using an 8 field XMM-Newton mosaic that extends out to the D25 isophote. The point source catalog from this survey was published by W15 (Williams+2015, J/ApJS/218/9). In addition to the catalog of W15, the authors utilized high-resolution observations from the Chandra ACIS Survey of M 33 (ChASeM33, Tullmann+2011, J/ApJS/193/31) for the purposes of obtaining X-ray spectral fits.
The authors detected 189 sources in the XMM-Newton field of view in the energy range of 0.2-12 keV. They constrained their nature by means of spectral analysis, hardness ratios, studies of the X-ray variability, and cross-correlations with catalogs in X-ray, optical, infrared, and radio wavelengths.
The authors identified and classified 12 background objects, five foreground stars, two X-ray binaries, one supernova remnant candidate, one super-soft source candidate and one ultra-luminous X-ray source. Among these sources, they classified for the first time three active galactic nuclei (AGN) candidates. the authors derived X-ray luminosity functions for the X-ray sources in M 83 in the 2-10 keV energy range, within and outside the D25 ellipse, correcting the total X-ray luminosity function for incompleteness and subtracting the AGN contribution. The X-ray luminosity function inside the D25 ellipse is consistent with that previously observed by Chandra. The Kolmogorov-Smirnov test shows that the X-ray luminosity function of the outer disc and the AGN luminosity distribution are uncorrelated with a probability of ~99.3%. The authors also found that the X-ray sources detected outside the D25 ellipse and the uniform spatial distribution of AGNs are spatially uncorrelated with a significance of 99.5%. They interpret these results as an indication that part of the observed X-ray sources are X-ray binaries in the outer disc of M 83.
The authors analyzed the public archival XMM-Newton data of M 83 (PIs: Watson, Kuntz). Three observations were analyzed, one pointing at the center of the galaxy (obs.1) and two in the south, which covered the outer arms with a young population of stars discovered with GALEX. The details of these observations are given in Table 1 of the reference paper (summarized below):
EPIC EPIC EPIC
No ObsID Date RA DE PN MOS1 MOS2 Mode
F Texp F Texp F Texp PN MOS
1 0110910201 2003-01-27 13:37:05.16 -29:51:46.1 t 21.2 m 24.6 m 24.6 EFF FF
2 0503230101 2008-01-16 13:37:01.09 -30:03:49.9 m 15.4 m 19.0 m 19.0 EFF FF
3 0552080101 2008-08-16 13:36:50.87 -30:03:55.2 m 25.0 m 28.8 m 28.8 EFF FF
where F is the filter (t for thin, m for medium), Texp is the exposure time
in ks, EFF = extended full frame imaging mode, and FF = full frame imaging
mode.
The central 0.28 deg2 region, where detailed optical follow-up observations were performed, contains ~ 170 X-ray sources (detection likelihood ML > 10), out of which 48 had already been detected by ROSAT. In this region 23 out of 29 optically selected quasars have been recovered. With a total of 110 classifications in their core sample, the authors have reached a completeness of ~65%. About one-third of the XMM-Newton sources are classified as type II AGN with redshifts mostly below 1.0. Furthermore, five high redshift type II AGN (2.2 <= z <= 2.8) have been detected.
This table contains the list of the 195 optical counterparts for 172 of the XMM-Newton X-ray sources given in Table 8 of the reference paper. It does not contain the full list of 328 X-ray sources given in Table A1 of the reference paper, nor the lists of marginal X-ray sources given in Appendix B of the reference paper.
This table contains the catalog of X-ray sources, with their optical and near-IR identifications, in the NGC 7000/IC 5070 (North America/Pelican) star formation complex. The final X-ray source list comprises 721 objects, of which there are 378 ACIS detections (of which 34 have an XMM-Newton counterpart), and 343 XMM-Newton-only detection. The chosen detection threshold, corresponding to approximately one spurious detection per field, ensures that no more than approximately ten of the 721 detections are spurious. The 11 XMM-Newton and Chandra fields analyzed in this study are listed in Tables 1 and 2, respectively, of the reference paper.
The authors have performed the first deep X-ray observation of the galaxies NGC 1512 and NGC 1510 with XMM-Newton to gain information on the population of X-ray sources and diffuse emission in this system of interacting galaxies.
They have identified and classified the sources detected in the XMM-Newton field of view by means of spectral analysis, hardness-ratios calculated with a Bayesian method, X-ray variability, and cross-correlations with catalogs in optical, infrared, and radio wavelengths. They also made use of archival Swift (X-ray) and Australia Telescope Compact Array (radio) data to better constrain the nature of the sources detected with XMM-Newton.
They detected 106 sources in the energy range of 0.2 - 12 keV, out of which 15 are located within the D25 regions of NGC 1512 and NGC 1510 and at least six sources coincide with the extended arms. They identified and classified six background objects and six foreground stars. In the reference paper, they discuss the nature of a source within the D25 ellipse of NGC 1512, whose properties indicate a quasi-stellar object or an intermediate ultra-luminous X-ray source. Taking into account the contribution of low-mass X-ray binaries and active galactic nuclei, the number of high-mass X-ray binaries detected within the D25 region of NGC 1512 is consistent with the star formation rate obtained in previous works based on radio, infrared optical, and UV wavelengths. The authors detected diffuse X-ray emission from the interior region of NGC 1512 with a plasma temperature of kT = 0.68(0.31-0.87) keV and a 0.3 - 10 keV X-ray luminosity of 1.3E+38erg/s, after correcting for unresolved discrete sources.
The galaxy pair NGC 1512/1510 was observed with XMM-Newton (ObsID: 0693160101) between 2012 June 16 (20:31 UTC) and 2012 June 17 (16:24 UTC) in a single, 63-ks exposure observation. The data analysis was performed through the XMM-Newton Science Analysis System (SAS) software (version 12.0.1). The observation was largely contaminated by high background due to proton flares. After rejecting time intervals affected by high background, the net good exposure time was reduced to 26.0 ks for PN, 39.8 ks for the MOS1 and 34.8 ks for the MOS2. For each instrument, the data were divided into five energy bands:
B1 : 0.2 - 0.5 keV
B2 : 0.5 - 1.0 keV
B3 : 1.0 - 2.0 keV
B4 : 2.0 - 4.5 keV
B5 : 4.5 - 12.0 keV
For the PN, data were filtered to include only single events (PATTERN = 0) in the energy band B__1, and single and double events (PATTERN <= 4) for the other energy bands. The authors excluded the energy range 7.2 - 9.2 keV to reduce the background produced by strong fluorescence lines in the outer detector area. For the MOS, single to quadruple events (PATTERN <= 12) were selected.
The source detection procedure is described in Section 2.1 of the reference paper. In the final step, the authors adopted a minimum likelihood of L = 6. They removed false detections (artifacts on the detectors or diffuse emission structures) by visual inspection. They detected 106 total point sources in the NGC 1512/1510 field of view.
The sources are concentrated within three regions of the cluster: in the vicinity of S Mon, within the large emission/reflection nebulosity southwest of S Mon, and along the broad ridge of molecular gas that extends from the Cone Nebula to the NGC 2264 IRS 2 field. From the extinction-corrected color-magnitude diagram of the cluster, ages and masses for the optically identified X-ray sources are derived. A median age of ~ 2.5 Myr and an apparent age dispersion of ~ 5 Myr are suggested by pre-main-sequence evolutionary models. The X-ray luminosity of the detected sources appears well-correlated with bolometric luminosity, although there is considerable scatter in the relationship. Stellar mass contributes significantly to this dispersion, while isochronal age and rotation do not. X-ray luminosity and mass are well correlated such that LX ~ (M/Msolar)1.5, which is similar to the relationship found within the younger Orion Nebula Cluster. No strong evidence is found for a correlation between E(H-K), the near-infrared color excess, and the fractional X-ray luminosity, which suggests that optically thick dust disks have little direct influence on the observed X-ray activity levels.
Among the X-ray-detected weak-line T Tauri stars, the fractional X-ray luminosity, LX/Lbol, is moderately well correlated with the fractional H-alpha luminosity, LH(alpha)/Lbol, but only at the 2-sigma level of significance. The cumulative distribution functions for the X-ray luminosities of the X-ray-detected classical and weak-line T Tauri stars within the cluster are comparable, assuming the demarcation between the two classes is at an H-alpha equivalent width of 10 Angstroms. However, if the non-detections in X-rays for the entire sample of H-alpha emitters known within the cluster are taken into account, then the cumulative distribution functions of these two groups are clearly different, such that classical T Tauri stars are underdetected by at least a factor of 2 relative to the weak-line T Tauri stars. Examining a small subsample of X-ray-detected stars that are probable accretors based on the presence of strong H-alpha emission and near-infrared excess, the authors conclude that definitive non-accretors are ~ 1.6 times more X-ray luminous than their accreting counterparts. In agreement with earlier published findings for the Orion Nebula Cluster, the authors find a slight positive correlation (valid at the 2-sigma confidence level) between LX/Lbol and the rotation period in NGC 2264 stars. The lack of a strong anti-correlation between X-ray activity and rotation period in the stellar population of NGC 2264 suggests that either the deeply convective T Tauri stars are rotationally saturated or that the physical mechanism responsible for generating magnetic fields in pre-main-sequence stars is distinct from the one that operates in evolved main-sequence stars.
NGC 2516 has been observed several times with XMM-Newton during the first two years of satellite operations for calibration purposes. The observations used in this analysis span a period of 19 months with exposure times between 10 and 20 ks. All of these observations have been performed with the thick filter. In the combined EPIC datasets the authors detected 431 X-ray sources with a significance level greater than 5.0 sigma, which should lead statistically to at most one spurious source in the field of view.
X-ray luminosity functions (XLFs) of galaxy populations are often used to characterize their properties. There are several methods for estimating the luminosities of X-ray sources with few photons. The authors have obtained spectral fits for the brightest 140 sources in the 2003 XMM-Newton observation of NGC 253, and compare the best-fitting luminosities of those 69 non-nuclear sources associated with NGC 253 with luminosities derived using other methods. They find the luminosities obtained from these various methods to vary systematically by a factor of up to 3 for the same data; this is largely due to differences in absorption. The authors therefore conclude that assuming Galactic absorption is probably unwise; rather, one should measure the absorption for the population. In addition, they find that standard estimations of the background contribution to the X-ray sources in the field are insufficient, and that the background active galactic nuclei (AGN) may be systematically more luminous than previously expected. However, the excess in their measured AGN XLF with respect to the expected XLF may be due to an as yet unrecognized population associated with NGC253.
XMM-Newton observations are susceptible to periods of high background levels, caused by increased flux of solar particles. The authors screened the data from each of the EPIC cameras (MOS1, MOS2 and pn), to remove flaring intervals. This process resulted in ~ 46 ks of good time for the pn and ~ 69 ks for the MOS cameras.
The authors combined the cleaned MOS and pn data, and ran the source detection algorithm provided with the XMM-Newton data analysis suite SAS version 7.0. They accepted sources with maximum-likelihood detections > 10 (equivalent to 4 sigma).
This table contains the properties of those X-ray sources which are correlated with optical cluster members (see Section 2.2 of the reference paper for details on the correlation procedure that was adopted), as well as the properties of those X-ray sources which are uncorrelated with any optical cluster members. The table lists the cross-identifications with optical catalogs for the candidate cluster sources along with their X-ray luminosities and X-ray to bolometric flux ratios, as well as the correlations between cluster members which were detected by XMM-Newton and those detected 7 years earlier by the ROSAT HRI instrument, along with the X-ray luminosities and flux ratios as determined by the HRI.
This table contains some of the results, namely an X-ray source catalog, from XMM-Newton observations of the Galactic globular cluster NGC 2808. The authors use X-ray spectral and variability analysis combined with ultraviolet observations made with the XMM-Newton optical monitor and published data from the Hubble Space Telescope to identify sources associated with the clusters. They compare the results of their observations with estimates from population synthesis models.
Five sources out of 96 X-ray sources detected above 4-sigma significance are likely to be related to NGC 2808. The authors find one quiescent neutron star low-mass X-ray binary candidate in the core of NGC 2808, and propose that the majority of the central sources in NGC 2808 are cataclysmic variables. An estimation leads to 20 +/- 10 cataclysmic variables with luminosity above 4.25 x 1031 erg s-1. Millisecond pulsars could also be present in the core of NGC 2808, and some sources outside the half-mass radius could possibly be linked to the cluster.
NGC 2808 was observed on February 1st 2005, for 41.8 kiloseconds (ks) with the three European Photon Imaging Cameras (EPIC MOS1, MOS2 and pn) on board the XMM-Newton observatory, in imaging mode, using a full frame window and a medium filter.
The catalog of the 610 X-ray sources detected in the 30'-diameter field of view of XMM-Newton is presented here, including the equatorial coordinates, logarithmic likelihoods and count rates for the three EPIC instruments and for various energy ranges, as well as the cross-identification of the X-ray sources with various optical/infrared catalogs (2MASS, GSC2.2, USNO B1.0, SSB06) and their most commonly used names (HD/HDE, CD, CPD, Segg., SBL98, Braes), with only the closest identifications being reported here.
This table contains information on 117 of the 119 X-ray sources (2 sources, a point source associated with 9 Sgr and an extended source associated with the Hourglass Nebula were excluded from this table by the authors) that were detected using the SAS source detection algorithms in the soft band (0.5 - 1.2 keV) of an EPIC observation of 9 Sgr which have either a combined likelihood >= 20 and are detected in the individual images from all 3 EPIC instruments with -ln p_i >= 3.0 or (in two cases) where clearly detected in 2 of the 3 instruments but fell outside of the FOV of the third. The faintest sources in this category have about 10-3 cts s-1 over the 0.5 - 1.2 keV band of the MOS instruments. Assuming a 1 keV thermal spectrum with a neutral hydrogen column density of 0.17 x 1022 cm-2, the faintest sources correspond to an observed flux of about 8.9 x 10-15 erg cm-2 s-1 and an unabsorbed flux of 13.1 x 10-15 erg cm-2 s-1 in the 0.5 - 5.0 keV energy range. Note that the corresponding observed flux in the 0.5 - 1.2 keV soft band would be 5.2 x 10-15 erg cm-2 s-1.
72 X-ray sources have a single optical counterpart from the Sung et al (2000, CDS Cat. <J/AJ/120/333>) catalog or in the SIMBAD database within a radius of less than 9 arcsec. The average angular separation between the X-ray source and the optical counterpart is 4.1 +/- 2.1 arcseconds. 17 X-ray sources have two or more optical stars falling within the 9 arcsec radius. Seven of these sources have at least one known H-alpha emission star inside their error box. 28 sources do not have an optical counterpart in the catalogue of Sung et al. The authors have cross-correlated these sources with the Guide Star Catalog and, in most cases, they find one or several GSC objects inside the 9 arcsec radius. These optical counterparts are usually very faint (V or R >=17) except for sources 91, 92 and 94 that have counterparts with R magnitudes 15.0, 14.6 and 13.3 respectively (note that these sources fall outside the area investigated by Sung et al.). Sources 93, 96, 98, 99, 100, 101, 102 and 112 have no GSC counterpart. Most of the objects in Table 3 are therefore X-ray sources with high X-ray to visual luminosity ratios. Given the galactic coordinates of NGC 6530 (l_II = 6.14, b_II = -1.38), the total galactic column density along this line of sight must be extremely large and the number of extragalactic sources in the soft detection energy band should be extremely low.
Very little is known about the evolution of stellar activity between the ages of the Hyades (0.8 Gyr) and the Sun (4.6 Gyr). To gain information on the typical level of coronal activity at a star's intermediate age, the authors have studied the X-ray emission from stars in the 1.9 Gyr-old open cluster NGC 752. They analyzed a ~ 140 ks Chandra observation of NGC 752 and a ~50 ks XMM-Newton observation of the same cluster. They detected 262 X-ray sources in the Chandra data and 145 sources in the XMM-Newton observation. Around 90% of the catalogued cluster members within Chandrás field of view are detected in the X-ray observation. The X-ray luminosity of all observed cluster members (28 stars) and of 11 cluster member candidates was derived. These data indicate that, at an age of 1.9 Gyr, the typical X-ray luminosity Lx of the cluster members with masses of 0.8 to 1.2 solar masses is 1.3 x 1028 erg s-1, which is approximately a factor of 6 times less intense than that observed in the younger Hyades. Given that Lx is proportional to the square of a star's rotational rate, the median Lx of NGC 752 is consistent, for t >= 1 Gyr, with a decaying rate in rotational velocities vrot ~ t-alpha with alpha ~ 0.75, steeper than the Skumanich relation (alpha ~ 0.5) and significantly steeper than that observed between the Pleiades and the Hyades (where alpha <0.3), suggesting that a change in the rotational regimes of the stellar interiors is taking place at an age of ~ 1 Gyr.
NGC 752 was observed for 49 ks by the XMM-Newton EPIC camera on February 5, 2003 starting at 23:29:25 UT, and the nominal pointing was towards J2000.0 RA and Declination of (01:57:38, +37:47:60), thus the XMM-Newton field-of-view (FOV) includes the Chandra FOV. For the source detection, the authors used the PWXDETECT code developed at Palermo Observatory and derived from the analogous Chandra PWDETECT code based on wavelet transform analysis. This allows the three EPIC exposures (PN, MOS1 and MOS2) to be combined in order to gain a deeper sensitivity with respect to the source detection based on single images. There were 145 point sources detected in the energy band 0.5 - 2.0 keV. An extended source (not listed in this present table), very likely a galaxy cluster, is also visible in the EPIC data.
The authors searched for 2MASS counterparts to the XMM-Newton sources using a search radius of 5 arcsec and found a counterpart for 38 sources. As for the Chandra data, all sources with a visible counterpart from DLM94 have also a 2MASS counterpart, so this leaves 15 XMM-Newton sources with a 2MASS counterpart and no counterpart in Daniel et al. (1994, PASP, 106, 281); of these, 3 were also detected by Chandra; of the other 12, 10 are outside the Chandra FOV, while two are within it (XMM-Newton sources 58 and 65). Source 65 was caught by XMM-Newton during the decay phase of a flare, which explains why it is not detected in the Chandra data. For source 58 there is no immediate explanation for this, since the light curve does not show evidence of a flare. No additional near-IR counterpart to the XMM-Newton sources was found within the Point Source Reject Table of the 2MASS Extended Mission.
NWAY extends previous distance- and sky density-based association methods and, using one or more priors (e.g. colors, magnitudes), weights the probability that sources from two or more catalogs are simultaneously associated on the basis of their observable characteristics. Here, counterparts have been determined using a Wide-field Infrared Survey Explorer (WISE) color-magnitude prior. A reference sample of 4,524 XMM/Chandra and Swift X-ray sources demonstrates a reliability of 97.4 per cent for XMMSL2 sources. Combining the results of this work and of the matching of ROSAT All-Sky Survey 2RXS sources also reported in this study (the results of the latter are available as the HEASARC's database table NWAYAWGROS) with Chandra-COSMOS data, the authors propose a new separation between stars and AGN in the X-ray/WISE flux-magnitude plane, that is valid over six orders of magnitude. The authors also release the NWAY code and its user manual. NWAY was extensively tested with XMM-COSMOS data.
Using two different sets of priors, the authors find an agreement of 96 per cent and 99 per cent with published Likelihood Ratio methods. Their results were achieved faster and without any follow-up visual inspection. With the advent of deep and wide area surveys in X-rays (e.g. SRG/eROSITA, Athena/WFI) and radio (ASKAP/EMU, LOFAR, APERTIF, etc.), NWAY will provide a powerful and reliable counterpart identification tool.
For all the available options, see the NWAY manual at https://github.com/JohannesBuchner/nway/raw/master/doc/nway-manual.pdf.
For each XMM-Newton source, its position, count rate, correlation with previous X-ray observation, and their associated errors are given. The detailed spectral information given in Table 5 of the reference paper for 17 selected X-ray sources is however not included in this HEASARC table.
The 13-hours deep field is centered on the sky coordinates RA(J2000) = 13 34 37.1, Dec (J2000) = +37 53 02.2. The XMM-Newton observations were carried out in three separate revolutions during June 2001 for a total exposure time of 200ks. Approximately 40% of the total observation time was affected by high particle background flares, arising from soft protons hitting the detector. The data were therefore temporally filtered to remove these high-background periods. Filtering reduced the total useful exposure time from ~200 ks to ~120 ks.
Throughout this study, the authors adopt a cosmology of H0 = 70 km s-1 Mpc-1, OmegaM = 0.27, and Lambda = 0.73.
The XMM-Newton and Chandra X-ray sources were matched with sources in the SDSS, WISE, UKIDSS, VHS, GALEX, FIRST and Herschel databases using the maximum likelihood estimator (MLE) method, as discussed in detail in Section 4 of the reference paper. This table contains the list of 5,220 sources detected in the SDSS Stripe 82 in archival, AO10 and AO13 XMM-Newton observations. A related table SDSSS82CXO contains the list of 1,146 Chandra sources detected in the SDSS Stripe 82.
Compared to the initial version of this catalog based on the 2013 paper, in the current version of the catalog the MLE matching between the XMM-Newton archival and AO10 source lists and ancillary catalogs was updated to include a 1 arcsecond systematic error added in quadrature to the emldetect reported positional error.
XMM-Newton observations of the sigma Ori cluster, centered on the hot star sigma Ori AB, were carried out as part of the Guaranteed Time of Roberto Pallavicini using both the EPIC MOS and PN cameras and the RGS instrument. The observation (ID 0101440301) started at 21:47 UT on March 23, 2002 and ended at 9:58 UT on March 24, 2002, for a total duration of 43 ks. The EPIC cameras were operated in Full Frame mode using the thick filter.
This table contains the combined list of 88 X-ray sources positionally (<= 5") associated with confirmed or candidate cluster members, and 66 X-ray sources with no such positional associations, detected above a significance threshold of 5 sigma. The two X-ray sources (source numbers 67 and 167) with 2 possible positional associations are listed twice, once for each positional association, with the X-ray information repeated. Thus, there are 156 entries in this HEASARC table.
Notice that X-ray sources with high extent (>40 arcseconds), e.g. supernova remnants and galaxy clusters, have been previously presented by Haberl et al. (2012, A&A, 545, A128) and are not included in this table.
To investigate the spectral behavior of all sources, the authors used hardness ratios HRi (i = 1, 2, 3, 4), defined by HRi = (Ri+1 - Ri)/(Ri+1 + Ri), where Ri is the count rate in energy band i as defined by:
Band Energy Range
1 0.2-0.5 keV
2 0.5-1.0 keV
3 1.0-2.0 keV
4 2.0-4.5 keV
5 4.5-12. keV
To increase statistics, the authors also calculated average HR_is,
combining all available instruments and observations. HRi is not given if
both rates Ri and Ri+1 are null or if the 1-sigma uncertainty of
Delta(HRi) covers the complete HR interval from -1 to +1. To convert an
individual count rate Ri of an energy band i into a setup-independent,
observed flux Fi, the authors calculated energy conversion factors (ECFs)
fi = Ri/Fi , as described in Sect. A.3 of the reference paper. For the
calculation, they assumed a universal spectrum for all sources, described by
a power-law model with a photon index of 1.7 and a photo-electric foreground
absorption by the Galaxy of NH,Gal = 6 x 1020 cm-2 (average for the SMC
main field in the H I map of Dickey & Lockman 1990, ARAA, 28, 215).
In addition to the fluxes for each detection, the authors calculated flux upper limits FUL for each observation and source, if the source was observed but not detected in an individual observation. As for the initial source detection, they used the emldetect task to fit sources, but kept the source positions fixed at the master positions and accepted all detection likelihoods in order to get an upper limit for the flux.
The authors describe the SPIDERS X-Ray Point Source Spectroscopic Catalog, considering its store of 11,092 observed spectra drawn from a parent sample of 14,759 ROSAT and XMM sources over an area of 5,129 deg2 covered in SDSS-IV by the eBOSS survey.
This catalog presents the SPIDERS XMM subsample of 3,196 sources which were drawn from the XMM Slew Survey source catalog, version 2 (XMMSL2), provided by the HEASARC in XMMSLEWFUL. The accompanying SPIDERSROS table contains the 21,288 sources drawn from the Second ROSAT All-Sky Survey (2RXS) Source Catalog, available from the HEASARC as RASS2RXS.
This program represents the largest systematic spectroscopic observation of an X-ray selected sample. A total of 10,970 (98.9%) of the observed objects are classified and 10,849 (97.8%) have secure redshifts. The majority of the spectra (10,070 objects) are active galactic nuclei (AGN), 522 are cluster galaxies, and 294 are stars.
The SDSS-IV/BOSS spectrographic observations are taken between 2014 and 2019.
The complete catalog of all X-ray sources (stellar and non-stellar) detected in the 28 XEST fields is presented in this table. The catalog provides X-ray coordinates, their uncertainties, X-ray count rates and their uncertainties, and X-ray hardness ratios for 2347 detected X-ray sources. If two XEST fields overlap, the same sources may have been identified twice, with different XEST IDs assigned, notice.
For complete and authoritative information on the XMM-Newton mission, policies, and data archive, refer to the web pages of the European Space Agency's (ESA's) XMM-Newton Science Operations Center at http://xmm.esac.esa.int/ and of NASA's XMM-Newton Guest Observer Facility at http://heasarc.gsfc.nasa.gov/docs/xmm/xmmgof.html
Notice that all priority C targets from AOs 1 through 19 which were never observed by XMM-Newton (and hence have expired) have been removed from this table. To check which targets have either already been observed by XMM-Newton or are on the short-term schedule to be observed in the next few weeks, users should examine the XMMMASTER table which is also contained in Browse. To find out which targets are currently scheduled to be observed in the next three months, the user should check the XMM-Newton Advanced Plan at http://xmm.esac.esa.int/external/xmm_sched/advance_plan.shtml
While abstracts are available for most proposals, there are a number of targets for which the HEASARC lacks the corresponding abstracts: e.g., the abstracts for AO-2 Guest Observer targets which have non-US PIs are not available.
The paper presents the source detection techniques and the "main" catalog, which includes 1700, 1582 and 814 sources detected by EMLDetect in the 0.5-8, 0.5-2 and 2-8keV bands, respectively; the number of unique sources is 1816. The authors extract spectra and derive fluxes from power-law fits for 398 sources with more than 40 counts in the 0.5-8 keV band. They compare the best-fit fluxes with those in the catalog, which were obtained assuming a common photon index Gamma of 1.7; the authors find no bulk difference between the fluxes, and a moderate dispersion s of 0.33 dex. Using wherever possible the fluxes from the spectral fits, the authors derive the 2-10 keV Log N-Log S distribution, which is consistent with a Euclidean distribution. Finally, they release the computer code for the tools which they developed for this project.
Sources were detected with a two-stage process. With the first pass at low significance, the authors got a list of candidate detections; and on the second pass they raised the significance threshold and derived accurate source parameters. Between the two passes, and because the second pass needs an input catalog, they identified the sources detected in more than one band. In the first pass, the SAS wavelet detection program ewavelet was run separately on each of the 0.5-2, 2-8 and 0.5-8 keV images of the entire mosaic, with a significance threshold of 4 sigma and the default wavelet scales (minimum 2 pixels, maximum 8 pixels, with a pixel size of 4). All parameters in this catalog which were derived from ewavelet have been given a prefix of 'wav' in this HEASARC representation so as to distinguish them from the parameters derived using EMLDetect. In the second pass, the authors used the SAS EMLDetect program to validate the detections, refine the coordinates and obtain maximum-likelihood estimates of the source counts, count rates and fluxes. The EMLDetect minimum likelihood was set at L = 4.6, as in Ranalli et al. (2013, A&A, 555, A42), which corresponds to a false-detection probability of 1.01 x 10-2. Together with the 4-sigma threshold for ewavelet, for the final catalog this yields a joint significance between 4 sigma and 5 sigma, but which cannot be further constrained without simulations.
This table contains the X-ray sources which were detected in the 7.1 deg2 XMM-Newton observations of the H-ATLAS field. The 1816 sources which were detected by both programs were presented in the main table in the reference paper (and are included in this HEASARC table where they are indicated by a value of the source_sample parameter of 'main'), while the 234 sources which were only detected by ewavelet were presented in the supplementary table in the reference paper (and are included in this HEASARC table where they are indicated by a value of the source_sample parameter of 'supp'). The same parameters were present in both the main and supplementary tables in the reference paper, but those parameters which came from EMLDetect are empty for the sources in the supplementary table. The parameters obtained using ewavelet (those parameters with the 'wav' prefix in their names) containing the source properties (counts, count rates, fluxes, exposure times, background, wavelet detection scale and source extent), while reported in this table for all sources, are actually only interesting for supplementary sources, according to the authors.
This table contains the basic data on a complete sample of 400 X-ray sources (389 of them belong to the BSS, 67 to the HBSS, with 56 X-ray sources in common) derived from the analysis of 237 suitable XMM-Newton fields (211 for the HBSS). At the flux limit of the survey, it covers a survey area of 28.10 (25.17 for the HBSS) square degrees. The extragalactic number-flux relationships (in the 0.5 - 4.5 keV and in the 4.5 - 7.5 keV energy bands) are in good agreement with previous and new results making the authors confident in the correctness of the data selection and their analysis.
From the individual analysis, the authors find that there seems to be an anticorrelation between the spectral index and the sources' hard X-ray luminosity, such that the average photon index for the higher luminosity sources (>1044 erg s-1) is significantly (>2 sigma) flatter than the average for the lower luminosity sources. They also find that the intrinsic column density distribution agrees with AGN unified schemes, although a number of exceptions are found (3% of the whole sample), which are much more common among optically classified type 2 AGN. The authors also find that the so-called "soft-excess", apart from the intrinsic absorption, constitutes the principal deviation from a power-law shape in AGN X-ray spectra and it clearly displays different characteristics, and likely a different origin, for unabsorbed and absorbed AGN. Regarding the shape of the average spectra, they find that it is best reproduced by a combination of an unabsorbed (absorbed) power law, a narrow Fe K-alpha emission line and a small (large) amount of reflection for unabsorbed (absorbed) sources.
X-ray sources were detected in the 3-Ms XMM-Newton observations of the Chandra Deep Field South. Source detection was done in two steps, first using the PWXDetect software, and then using emldetect. 339 Sources detected by both programs are presented in the main tables, while 74 sources only detected by PWXDetect are presented in the supplementary tables. The 2-10 and 5-10 keV bands were analyzed separately.
This HEASARC table contains the main sample of 339 sources detected in the 2-10 keV band in the XMM-CDFS survey. (The table of 5-10 keV XMM-CDFS sources is also available at the HEASARC as the XMMCDFS510 table). This table does not include the 74 supplementary sources which were detected only with PWXDetect. These supplementary sources were on average detected at low significance; many of them were on the borders of the FOV; and a few were in crowded fields where EMLDetect had trouble separating the different PSF components. Nevertheless, 4 of these sources were bright enough that a spectrum could be extracted.
In this paper, the authors present the data reduction of the XMM-CDFS observations, the method for source detection in the 2-10 and 5-10 keV bands, and the resulting catalogs. A number of 339 and 137 sources are listed in the above bands with flux limits of 6.6 x 10-16 and 9.5 x 10-16 erg/s/cm2, respectively. The flux limits at 50% of the maximum sky coverage are 1.8 x 10-15 and 4.0 x 10-15 erg/s/cm2, respectively. The catalogs have been cross-correlated with the Chandra ones: 315 and 130 identifications have been found with a likelihood-ratio method, respectively. 15 new sources, previously undetected by Chandra, have been found; 5 of them lie in the 4-Ms area. Redshifts, either spectroscopic or photometric, are available for ~92% of the sources. The number counts in both bands are presented and compared to other works. The survey coverage has been calculated with the help of two extensive sets of simulations, one set per band. The simulations have been produced with a newly-developed simulator, written with the aim of the most careful reproduction of the background spatial properties. For this reason, the authors present a detailed decomposition of the XMM-Newton background into its components: cosmic, particle, and residual soft protons. The three components have different spatial distributions. The importance of these three components depends on the band and on the camera; the particle background is the most important one (80-90% of the background counts), followed by the soft protons (4-20%).
X-ray sources were detected in the 3-Ms XMM-Newton observations of the Chandra Deep Field South. Source detection was done in two steps, first using the PWXDetect software, and then using emldetect. 137 Sources detected in the 5-10 keV band by both programs are presented in the main table, while 61 5-10 keV sources only detected by PWXDetect are presented in the supplementary table. The 2-10 and 5-10 keV bands were analyzed separately.
This HEASARC table contains the main sample of 137 sources detected in the 5-10 keV band in the XMM-CDFS survey. (The table of 2-10 keV XMM-CDFS sources is also available at the HEASARC as the XMMCDFS210 table.) This table does not include the 61 supplementary sources which were detected only with PWXDetect. These supplementary sources were on average detected at low significance; many of them were on the borders of the FOV; and a few were in crowded fields where EMLDetect had trouble separating the different PSF components. Nevertheless, 4 of these sources were bright enough that a spectrum could be extracted.
The authors have used a subset of the XMM-Newton sources, which have Chandra positions, to determine the best method of obtaining optical identifications of sources with only XMM-Newton positions. They found optical identifications for 79% of the XMM-Newton sources for which there were deep optical images. The sources without optical identifications are likely to be optically fainter and have higher redshifts than the sources with identifications. The authors have estimated 'photometric redshifts' for the identified sources, calibrating their method using ~200 galaxies in the fields with spectroscopic redshifts. They find that the redshift distribution has a strong peak at z ~ 0.7.
Herein optical and X-ray properties for 545 Type 1 AGN in XMM-COSMOS are presented. For each source, X-ray ID, spectroscopic redshift, photometric redshift, upper error on the photometric redshift, lower error on the photometric redshift, logarithm of the monochromatic luminosity at 2500 Angstroms, logarithm of the monochromatic luminosity at 2 keV, alphaox, logarithm of the 2-10 keV luminosity, logarithm of the bolometric luminosity in solar units, bolometric correction, photometric classification, logarithm of the Eddington ratio, logarithm of the black hole mass in solar masses, and a flag for the 2-10 keV detection (flag = 1 [343 entries] means a detection in the 2-10 keV band, while flag = 0 is for 2-10 keV upper limits) are given.
The analysis was performed using the XMM-SAS data analysis package in the 0.5-2 keV, 2-10 keV and 5-10 keV energy bands. Source detection has been performed using a maximum likelihood technique especially designed for raster scan surveys. The completeness of the catalog as well as log N-log S and source density maps have been calibrated using Monte Carlo simulations.
This is the catalogue of point-like X-ray sources detected with the EPIC CCD cameras. The catalogs contains a total of 1887 unique sources detected in at least one band with likelihood parameter det_ml > 10. The survey, which shows unprecedented homogeneity, has a flux limit of ~1.7 x 10-15 erg/cm2/s, ~9.3 x 10-15 erg/cm2/s and ~1.3 x 10-14 erg/cm2/s over 90% of the area (1.92 deg2) in the 0.5-2 keV, 2-10 keV and 5-10 keV energy bands, respectively.
In addition, in this study the authors released revised photometric redshifts for the 1735 optical counterparts of the XMM-detected sources over the entire 2 deg2 of COSMOS, and these are the sources listed in the present table. For 248 sources, their updated photometric redshift differs from the previous release by Delta-z > 0.2. These changes are predominantly due to the inclusion of newly available deep H-band^ photometry (HAB = 24 mag). The authors illustrate once again the importance of a spectroscopic training sample and how an assumption about the nature of a source together, with the number and the depth of the available bands, influences the accuracy of the photometric redshifts determined for AGN. These considerations should be kept in mind when defining the observational strategies of upcoming large surveys targeting AGNs, such as eROSITA at X-ray energies and the Australian Square Kilometre Array Pathfinder Evolutionary Map of the Universe in the radio band.
This table contains the photometric redshifts and related quantities for 1735 XMM-Newton sources over the entire 2 square degrees of the COSMOS field. Notice that in the original as-published paper no positional information was provided. The HEASARC has assumed that the source numbers used in the present catalog are in the same source numbering scheme as used by Cappelluti et al. (2009, A&A, 497, 635, the XMM-Newton Wide-Field Survey in the COSMOS Field Point-like X-ray Source Catalog, available at the HEASARC as the XMMCOSMOS table) and thus obtained the positions and (position-based) names corresponding to these X-ray sources from the latter.
The authors provide X-ray source lists in the customary soft and hard energy bands (0.5-2 keV and 2-10 keV, respectively) for a total of 5572 objects in the catalog limited to 10 ks exposures presented in this table, and a total of 6721 objects in the deep full-exposure 2XLSSd catalog (available at the HEASARC as the XMMLSSDEEP table), above a detection likelihood of 15 in at least one band. At the XMMLSS web site which they maintain (http://cosmosdb.iasf-milano.inaf.it/XMM-LSS/), the authors also provide a multiwavelength catalog, cross-correlating their list of X-ray sources with infrared, near-infrared, optical and ultraviolet catalogs. Customary data products, such as X-ray FITS images and thumbnail images from the Canada-France-Hawaii Telescope Legacy Survey and the Spitzer Wide-Area Infrared Extragalactic Survey, are made available there, together with their data base in Milan, which can be queried interactively.
In this table, the authors provide the source list for the full area (11.1 square degrees) of the XMM-LSS, with a total of 5572 point-like or extended sources above a detection likelihood of 15 in either the 0.5-2 or 2-10 keV bands. This table, the "standard" 2XLSS catalog containing the results of the analysis of the survey area using uniform 10-ksec exposures for all pointings longer than 10 ksec, lists the main X-ray parameters, while further multiwavelength parameters and data products (X-ray images and optical/IR thumbnails) are available at the Milan XMM-LSS database site referenced above. It supersedes the first XMM-LSS version (Pierre et al. 2007, available at the HEASARC as the XMMLSS table).
Analogously to Paper I, only sources with an off-axis angle < 13 arcmin were processed by the authors' X-ray data processing pipeline software, XAMIN. The catalog includes all the extended sources classified in the customary C1 and C2 classes (see Section 3.6 of Paper II) plus all point-like sources with a point source detection likelihood (DET_LH) greater than 15 (so-called non-spurious sources).
The authors wished to investigate the environmental properties of the different types of the XMM-LSS X-ray sources by defining their environment using the i'-band CFHTLS W1 catalog of optical galaxies to a magnitude limit of 23.5 magnitudes. They have classified 4,435 X-ray selected sources on the basis of their spectra, spectral energy distributions (SEDs), and X-ray luminosities, and estimated their photometric redshifts, which have a 4-11 band photometry with an accuracy of sigma[Deltaz/(1+zsp)] = 0.076, with 22.6% outliers for i' < 26 mag. The authors estimated the local overdensities of 777 X-ray sources that have spectro-z or photo-z calculated by using more than seven bands (accuracy of sigma[(Deltaz/(1+zsp)] = 0.061, with 13.8% outliers) within the volume-limited region defined by 0.1 <= z <= 0.85 and -23.5 < M_i'_ < -20.
Although X-ray sources may be found in variety of environments, a high fraction (~55-60%), as verified by comparing with the random expectations, reside in overdense regions. The galaxy overdensities within which X-ray sources reside show a positive recent redshift evolution (at least for the range studied; z <~ 0.85). The authors also find that X-ray selected galaxies, when compared to AGN, inhabit significantly higher galaxy overdensities, although their spatial extent appear to be smaller than that of AGN. Hard AGN (harness ratios HR >= -0.2) are located in more overdense regions than soft AGN (HR < -0.2), which is clearly seen in both redshift ranges, although it appears to be stronger in the higher redshift range (0.55 < z < 0.85). Furthermore, the galaxy overdensities (with delta > 1.5, where delta is defined in equation (3) of the reference paper) within which soft AGN are embedded appear to evolve more rapidly compared to the corresponding overdensities around hard AGN.
This table contains the spectroscopic and/or photometric redshifts for 4,206 X-ray selected sources in the XMM-LSS field which have optical counterparts and have been classified by the authors.
The authors provide X-ray source lists in the customary soft and hard energy bands (0.5-2 keV and 2-10 keV, respectively) for a total of 6721 objects in the deep full-exposure 2XLSSd catalog presented in this table, and 5572 objects in the catalog limited to 10 ks exposures (available at the HEASARC as the XMMLSS10KS table), above a detection likelihood of 15 in at least one band. At the XMMLSS web site which they maintain (http://cosmosdb.iasf-milano.inaf.it/XMM-LSS/), the authors also provide a multiwavelength catalog, cross-correlating their list of X-ray sources with infrared, near-infrared, optical and ultraviolet catalogs. Customary data products, such as X-ray FITS images and thumbnail images from the Canada-France-Hawaii Telescope Legacy Survey and the Spitzer Wide-Area Infrared Extragalactic Survey, are made available there, together with their data base in Milan, which can be queried interactively.
In this table, the authors provide the source list for the full area (11.1 square degrees) of the XMM-LSS, with a total of 6721 point-like or extended sources above a detection likelihood of 15 in either the 0.5-2 or 2-10 keV bands. This table, the 2XLSSd "deep catalog" version containing the result of the analysis of the full-length exposures, lists the main X-ray parameters, while further multiwavelength parameters and data products (X-ray images and optical/IR thumbnails) are available at the Milan XMM-LSS database site referenced above. It supersedes the first XMM-LSS version (Pierre et al. 2007, available at the HEASARC as the XMMLSS table).
Analogously to Paper I, only sources with an off-axis angle < 13 arcmin were processed by the authors' X-ray data processing pipeline software, XAMIN. The catalog includes all the extended sources classified in the customary C1 and C2 classes (see Section 3.6 of Paper II) plus all point-like sources with a point source detection likelihood (DET_LH) greater than 15 (so-called non-spurious sources).
In a flux-limited sample of 829 point-like sources in the optical band with g' <= 22 magnitudes and the 0.5-2 keV flux (f_0.5-2keV) > 10-15 erg/cm2/s, the authors observed 693 objects and obtained reliable spectroscopic identification for 487 sources, approximately 59% of the overall sample. The authors therefore have increased the number of identifications in this field by a factor close to 5. Galactic stellar sources represent about 15% of the total (74/487). About 54% (265/487) are broad-line active galactic nuclei (AGN) spanning redshifts between 0.15 and 3.87 with a median value of 1.68. The optical-to-X-ray spectral index (alpha_ox) of the broad-line AGN is 1.47 +/- 0.03, typical of optically selected type I quasars, and is found to correlate with the rest-frame X-ray and optical monochromatic luminosities at 2 keV and 2500 Angstroms, respectively. Consistent with previous studies, the authors find that alpha_ox is not correlated with z. In addition, 32 and 116 X-ray sources are, respectively, absorption- and emission-line galaxies at z < 0.76. From a line ratio diagnostic diagram, it is found that in about 50% of these emission-line galaxies, the emission lines are powered significantly by the AGN. 30 of the XMM sources are detected at one or more radio frequencies (see Table 5 in the published paper). In addition, 24 sources (listed in table 4 of the published paper) have ambiguous identification: in eight cases, two XMM sources have a single optical source within 6 arcsec of each of them, whereas two and 14 XMM sources have, respectively, three and two possible optical sources within 6 arcsec of each of them. Spectra of multiple possible counterparts were obtained in such ambiguous cases.
This HEASARC table contains the 487 sources which were reliably spectroscopically identified.
This database table contains the list of observations which have already been made by the XMM-Newton observatory, as well as those which are scheduled to be made in the near future (usually a a few weeks to a month ahead of the present). It does not contain observations which are scheduled to be performed further in the future, nor does it contain accepted observations which have not yet been scheduled. The list of all accepted XMM-Newton observations, including a number of ones which are unlikely to ever be carried out, such as accepted priority C targets, is available in the XMMAO Browse table.
This table includes entries for both pointed data and for data obtained during spacecraft slews. The slew observations all have obsid values beginning with the digit 9 and, because they were not made at a fixed position, lack any positional information such as RA and Declination.
Some XMM-Newton observations for which the archived data has become publicly available as indicated by the public_date parameter value, i.e., the proprietary period has expired, are not currently available at the HEASARC: such cases will have values of 'N' for the data_in_heasarc parameter. These datasets in most cases are available at the ESA XMM-Newton Science Archive (XSA) at http://nxsa.esac.esa.int/nxsa-web/.
For much more detailed information on the XMM-Newton instruments and their operation, please refer to the XMM-Newton Users Handbook at http://heasarc.gsfc.nasa.gov/docs/xmm/uhb/.
This is a catalog of X-ray emitters amongst early-type stars following a correlation between the Reed (2003, AJ, 125, 2531) Catalog of galactic OB Stars and the 2XMMi Catalog (Watson et al. 2009, A&A, 493, 339). See the reference paper for more details.
Differences between the current OMCat and the previous version of the OMCat (which was designated as XMMOMOBJ) are improved coordinates, improved quality flags, and a reduced number of spurious sources. The OM reduction was done with the standard ESAS software, with post-processing to apply the coordinate corrections in a more consistent manner. There is a major change in the way the data are represented in the table. In the previous XMMOMOBJ table a separate row was generated for each filter. In the current XMMOMCAT table each observation of each object generates only a single row regardless of how many filters were used. Unused filters have nulls while filters where the object is not detected have nulls for the detection parameters but a non-zero value for exposure.
The table includes information for each filter and averaged information for the object as a whole. Only filters in which the object was detected are used in the averages. The parameters in this table comprise two sets: parameters describing the detection overall including id's and mean values, and values specific to the individual bands. There are three possible situations for the band data:
(1) If there was no exposure in that band, then all fields for that band will be null.
(2) If there was some exposure in the band but the object was not detected in that band, then the exposure field will give the actual exposure, but all of the other fields for that band will be null.
(3) If the object was detected, then all of the fields for the band should be filled in.
The filters included are V, B, U, UVW1, UVM2, UVW2 and white (i.e., unfiltered).
Photometric data of 1129 CDFS sources are provided in the main catalog, and optical/UV/X-ray photometric and spectroscopic information from other surveys are also included. The stacking extends the detection limits by ~1 mag in the three UV bands, contributing 30% of the catalogued UV sources. The comparison with the available measurements in similar spectral bands confirms the validity of the XMM-OM calibration. The combined COMBO-17/X-ray classification of the "intermediate" sources (e.g. optically diluted and/or X-ray absorbed AGN) is also discussed in the reference paper.
The number of observations (OBSIDs) included in the catalog is 12,057. This table (XMMOMSUOB) contains the list of these observations and their characteristics, giving for each observation the filters used, the exposure time for each filter, the number of sources detected in each filter and the detection magnitude limit for each filter. The total number of entries in this release is 9,920,390. They correspond to 6,659,554 unique sources, of which 1,225,117 have multiple entries in the source table, corresponding to different observations. This list of sources is available at the HEASARC as the XMMOMSUSS table.
The documentation on the first release of this catalog is available at http://www.mssl.ucl.ac.uk/www_astro/XMM-OM-SUSS/Summary.shtml.
The number of observations (OBSIDs) included in the catalog is 12,057. The total number of entries in this release is 9,920,390. They correspond to 6,659,554 unique sources, of which 1,225,117 have multiple entries in the source table, corresponding to different observations. For each entry, positional and photometric data (count rate, magnitude and flux) and quality flags for each measurement are provided. The description of the previous release of the catalog can be found in Page M.J. et al. (2012, MNRAS, 426, 903).
U, B, V, UVW2, UVM2 and UVW1 refer to the filter bandpasses defined in the Source Properties: Filter Set section of the MSSL documentation for this catalog: http://www.mssl.ucl.ac.uk/www_astro/XMM-OM-SUSS/SourcePropertiesFilters.shtml.
There is a second, related table which gives a summary of the observations from which the XMM-SUSS6.1 sources listed in this table have been detected and measured. That summary table is available at the HEASARC as the XMMOMSUOB table.
This table contains 145 entries, 67 of which are new (as of Paper III) optically confirmed clusters (marked by values of ref_source = 'Paper III') and 78 of which are clusters from Paper II which have now been spectroscopically confirmed (marked by values of ref_source = 'Paper II'). The tabular information on the 530 clusters that was presented in Paper II of this set of papers is available as the HEASARC XMMSDSSGCS table).
The following parameters were obtained from the current optical-band cluster detection algorithm: sdss_dr10_bcg_id, sdss_dr10_bcg_ra, sdss_dr10_bcg_dec, bcg_rmag, redshift, num_spect_members, phot_redshift, num_phot_members, and spatial_offset.
The catalog has two subsamples: (i) a cluster sample comprising 345 objects with their X-ray spectroscopic temperature and flux from the spectral fitting; (these objects are identified by having values for the table_sample parameter of 1 in this HEASARC implementation of the catalog) and (ii) a cluster sample consisting of 185 systems with their X-ray flux from the 2XMMi-DR3 catalog, because their X-ray data are insufficient for spectral fitting (these objects are identified by having values for the table_sample parameter of 2 herein). For each cluster, the catalog also provides the X-ray bolometric luminosity and the cluster mass at R500 based on scaling relations and the position of the likely brightest cluster galaxy (BCG). The updated LX - T relation of the current sample with X-ray spectroscopic parameters is presented in the paper. The authors found the slope of the LX - T relation to be consistent with published ones. They see no evidence for evolution in the slope and intrinsic scatter of the LX - T relation with redshift when excluding the low-luminosity groups.
This catalog of X-ray selected galaxy clusters and groups supersedes and subsumes the first release of the 2XMMi/SDSS Galaxy Cluster Survey, comprising 175 clusters of galaxies, which was presented in Takey et al. (2011, A&A, 534, A120).
This is the first release of XMMSL2 which contains data taken between revolutions 314 and 2758. The previous catalog was called XMMSL1_Delta6 and contained slews up to revolution 2441. XMMSL2 has been generated from 2114 slews, executed between 2001-08-26 and 2014-12-31, revolutions 314 to 2758. Not all slews made in this period have been used; slews with particularly high background throughout the slew or which gave processing problems have been rejected.
A full discussion of the differences between XMMSL2 and XMMSL1 is given in Section 12 of the XMMSL2 Users Guide at https://www.cosmos.esa.int/web/xmm-newton/xmmsl2-ug.
The starting point was a sample of 487 sources detected in the XSS (up to and including release XMMSL1d2) at high galactic latitude in the hard band. Through cross-correlation with published source catalogs from surveys spanning the electromagnetic spectrum from radio through to gamma-rays, they find that 45% of the sources have likely identifications with normal/active galaxies. A further 18% are associated with other classes of X-ray object (nearby coronally active stars, accreting binaries, clusters of galaxies), leaving 37% of the XSS sources with no current identification. The authors go on to define an XSS extragalactic sample comprised of 219 galaxies and active galaxies selected in the XSS hard band. They investigate the properties of this extragalactic sample including its X-ray log N - log S distribution, and it is this sample that is contained in this table.
The authors find that, in the low-count limit, the XSS is, as expected, strongly affected by Eddington bias. There is also a very strong bias in the XSS against the detection of extended sources, most notably clusters of galaxies. A significant fraction of the detections at and around the low-count limit may be spurious. Nevertheless, it is possible to use the XSS to extract a reasonably robust sample of extragalactic sources, excluding galaxy clusters. The differential log N - log S relation of these extragalactic sources matches very well to the HEAO-1 A2 all-sky survey measurements at bright fluxes and to the 2XMM source counts at the faint end. The substantial sky coverage afforded by the XSS makes this survey a valuable resource for studying X-ray bright source samples, including those selected specifically in the hard 2 - 10 keV band.
This is the first release of XMMSL2 which contains data taken between revolutions 314 and 2758. The previous catalog was called XMMSL1_Delta6 and contained slews up to revolution 2441. XMMSL2 has been generated from 2114 slews, executed between 2001-08-26 and 2014-12-31, revolutions 314 to 2758. Not all slews made in this period have been used; slews with particularly high background throughout the slew or which gave processing problems have been rejected.
A full discussion of the differences between XMMSL2 and XMMSL1 is given in Section 12 of the XMMSL2 Users Guide at https://www.cosmos.esa.int/web/xmm-newton/xmmsl2-ug.
The catalog contains source detections drawn from a total of 13,243 XMM-Newton EPIC observations made between 2000 February 1 and 2022 December 31; all datasets included were publicly available by 2022 December 31 but not all public observations are included in this catalog. For net exposure time >= 1ksec, the net area of the catalog fields taking account of the substantial overlaps between observations is ~1,328 deg2.
4XMM-DR13 contains 983,948 X-ray detections above the processing likelihood threshold of 6. These X-ray detections relate to 656,997 unique X-ray sources. A significant fraction of sources (129,133, 20%) have more than one detection in the catalog (up to 90 repeat observations in the most extreme case).
The catalog distinguishes between extended emission and point-like detections. Parameters of detections of extended sources are only reliable up to the maximum extent measure of 80 arcseconds. There are 91,763 detections of extended emission, of which 20,971 are 'clean' (in the sense that they were not flagged).
Due to intrinsic features of the instrumentation as well as some shortcomings of the source detection process, some detections are considered to be spurious or their parameters are considered to be unreliable. It is recommended to use a detection flag and an observation flag as filters to obtain what can be considered a 'clean' sample. There are 854,095 out of 983,948 detections that are considered to be clean (i.e., summary flag < 3).
For 353,538 detections, EPIC time series and 353,821 detections, EPIC spectra were automatically extracted during processing, and a chi2-variability test was applied to the time series. 8,029 detections in the catalog are considered variable, within the timespan of the specific observation, at a probability of 10-5 or less based on the null-hypothesis that the source is constant. Of these, 6,039 have a summary flag <3.
The median flux (in the total photon-energy band 0.2 - 12 keV) of the catalog detections is ~ 2.2 x 10-14 erg/cm2/s; in the soft energy band (0.2 - 2 keV) the median flux is ~ 5.2 x 10-15, and in the hard band (2 - 12 keV) it is ~1.2 x 10-14. About 23% have fluxes below 1 x 10-14 erg/cm2/s. The flux values from the three EPIC cameras are, overall, in agreement to ~10% for most energy bands. The median positional accuracy of the catalog point source detections is generally < 1.57 arcseconds (with a standard deviation of 1.43 arcseconds).
With 4XMM-DR13, the team also released 4XMM-DR13s, available from HEASARC as XMMSTACK, a new version of the stacked catalog built from 9,796 4XMM-DR13 overlapping observations. 4XMM-DR13s contains 1,688 stacks (or groups). Most of the stacks are composed of 2 observations and the largest has 372. The catalog contains 401,596 sources, of which 310,478 have several contributing observations. Stacking observations allows yet fainter sources to be detected in sky regions observed more than once, increasing the number of detections and uncovering long-term variability on repeatedly observed objects. 4XMM-DR13s reaches a depth of ~2.5 x 10-15 and ~6.8 x 10-15 erg/cm2/s in the soft (0.2-2keV) and hard (2-12 keV) X-ray band, respectively.
The energy bands used in the 4XMM-DR13 processing were the same as for the 3XMM catalog.
The following are the basic energy bands:
1 = 0.2 - 0.5 keV 2 = 0.5 - 1.0 keV 3 = 1.0 - 2.0 keV 4 = 2.0 - 4.5 keV 5 = 4.5 - 12.0 keV
while these are the broad energy bands:
6 = 0.2 - 2.0 keV soft band, no images made 7 = 2.0 - 12.0 keV hard band, no images made 8 = 0.2 - 12.0 keV total band 9 = 0.5 - 4.5 keV XID band
The survey is based on 26 XMM-Newton observations, obtained at |b| < 20 degrees, distributed over a large range in Galactic longitudes and covering a summed area of 4 deg2. The flux limit of this survey is 2 x 10-15 erg/cm2/s in the soft (0.5 - 2 keV) band and 1 x 10-14 erg/cm2/s in the hard (2 - 1 2keV) band. A total of 1319 individual X-ray sources have been detected. Using optical follow-up observations supplemented by cross-correlation with a large range of multi-wavelength archival catalogs, the authors identify 316 X-ray sources. This constitutes the largest group of spectroscopically identified low-latitude X-ray sources at this flux level. The majority of the identified X-ray sources are active coronae with spectral types in the range A to M at maximum distances of ~1 kpc. The number of identified active stars increases towards late spectral types, reaching a maximum at K. Using infrared colors, the authors classify 18% of the stars as giants. The observed distributions of FX/FV, X-ray and infrared colors indicates that their sample is dominated by a young (100 Myr) to intermediate (600 Myr) age population with a small contribution of close main-sequence or evolved binaries. The authors find other interesting objects such as cataclysmic variables (d ~ 0.6 - 2 kpc), low-luminosity high-mass stars (likely belonging to the class of Gamma-Cas-like systems, d ~ 1.5 - 7 kpc), T Tauri and Herbig-Ae stars. A handful of extragalactic sources located in the highest Galactic latitude fields could be optically identified. For the 20 fields observed with the EPIC pn camera, the authors have constructed log N(>S) - log S curves in the soft and hard bands. In the soft band, the majority of the sources are positively identified with active coronae and the fraction of stars increases by about one order of magnitude from b = 60 degrees to b = 0 degrees at an X-ray flux of 2 x 10-14 erg/cm2/s. The hard band is dominated by extragalactic sources, but there is a small contribution from a hard Galactic population formed by CVs, HMXB candidates or Gamma-Cas-like systems and by some active coronal stars that are also detected in the soft band. At b = 0 degrees, the surface density of hard sources brighter than 1 x 10-13 erg/cm2/s steeply increases by one order of magnitude from l = 20 degrees to the Galactic center region (l = 0.9 degrees).
This HEASARC table contains 739 X-ray sources detected in the 26 different fields observed in this study and listed in Tables 8 - 33, inclusive, of the reference paper. These 739 sources have the best XMM quality, i.e. the summary flag sum_flag which contains information about flags set automatically and manually for a given source is zero, meaning that there are no negative flags for the source detection, have either a 2MASS, USNO, GSC, or SDSS counterpart, whatever the probability of identification is, or have some information via SIMBAD or the authors own imaging or spectroscopic observations. For each X-ray source, its X-ray parameters are summarized, listing the pn count rates, and information on optical and infrared counterparts is provided. The properties of the 26 target fields are given in Table 1 of the reference paper, along with the breakdown of source classes in each field.
This table contains the list of 19,637 detections of the 4,330 unique X-ray sources which comprise the authors' sample. The list of 4,330 unique X-ray sources and their classifications is also available as the HEASARC XMMSSCLWBS table.
Stacked source detection aims at exploring the multiply observed sky regions and exploit their survey potential, in particular to study the long-term behavior of X-ray emitting sources. It thus makes use of the long(er) effective exposure time per sky area and offers the opportunity to investigate flux variability directly through the source detection process. The main catalog properties are summarized in the table below, the data processing and the stacked source detection are described in the processing summary. To ensure detection quality, background levels are assessed, and event-based astrometric corrections are applied before running source detection. After source detections, problematic detections and detection parameters are flagged by an automated algorithm. All detections are screened visually, and obviously spurious sources are flagged manually.
This table contains the parameters of the 401,596 unique sources (provided in this table) derived simultaneously from all of the observations (provided in the associated table of observations referred to as XMMSTACKOB) at the fitted position.
The authors referred to the EPIC instruments with the following designations: PN, M1 (MOS1), and M2 (MOS2). The energy bands used in the 4XMM processing were the same as for the 3XMM catalog.
The following are the basic energy bands:
1: 0.2-0.5 keV
2: 0.5-1.0 keV
3: 1.0-2.0 keV
4: 2.0-4.5 keV
5: 4.5-12.0 keV
All-EPIC values cover the energy range 0.2-12.0 keV.
The full catalog documentation can be found at https://xmmssc.aip.de/.
comparison with the previous stacked catalogs, 4XMM-DR13s through 3XMM-DR7s:
4XMM-DR13s 4XMM-DR12s 4XMM-DR11s 4XMM-DR10s 4XMM-DR9s 3XMM-DR7s
Number of stacks 1,688 1,620 1,475 1,396 1,329 434
Number of observations 9,796 9,355 8,292 7,803 6,604 789
Time span first to last observation Feb 01, 2000 Feb 01, 2000 Feb 03, 2000 Feb 03, 2000 Feb 03, 2000 Feb 20, 2000
-- Nov 29, 2022 -- Dec 04, 2021 -- Dec 17, 2020 -- Dec 14, 2019 -- Nov 13, 2018 -- Apr 02, 2016
Approximate sky coverage (sq. deg.) 650 625 560 540 485 150
Approximate multiply observed sky area(sq. deg) 420 400 350 335 300 100
Total number of sources 401,596 386,043 358,809 335,812 288,191 71,951
Sources with several contributing observations 310,478 298,626 275,440 256,213 218,283 57,665
Multiply observed sources with flag 0 or 1 262,842 252,445 233,542 216,999 191,497 55,450
Multiply observed with a total detection 251,555 241,880 224,178 208,921 181,132 49,935
likelihood of at least six
Multiply observed with a total detection 213,812 205,394 189,556 176,680 153,487 42,077
likelihood of at least ten
Total measurements 1,683,264 1,592,263 1,421,966 1,322,299 1,033,264 216,393
Maximum exposures per source 170 155 140 140 103 69
Maximum observations per source 77 70 65 65 40 23
Maximum on-time per source 2.8 Ms 2.8 Ms 2.8 Ms 2.8 Ms 1.9 Ms 1.3 Ms
Stacked source detection aims at exploring the multiply observed sky regions and exploit their survey potential, in particular to study the long-term behavior of X-ray emitting sources. It thus makes use of the long(er) effective exposure time per sky area and offers the opportunity to investigate flux variability directly through the source detection process. The main catalog properties are summarized in the table below, the data processing and the stacked source detection are described in the processing summary. To ensure detection quality, background levels are assessed, and event-based astrometric corrections are applied before running source detection. After source detections, problematic detections and detection parameters are flagged by an automated algorithm. All detections are screened visually, and obviously spurious sources are flagged manually.
This table contains the source parameters from the individual observations in the stacked catalog, 4XMM-DR13s. The parameters are derived from the simultaneous source-detection fit to all stacked observations at the common source position for each observation that covers a source, amounting to 1,683,264 measurements. The mean source parameters from stacked source detection are provided in the associated main table 4XMM-DR13s, referred to as XMMSTACK.
The authors referred to the EPIC instruments with the following designations: PN, M1 (MOS1), and M2 (MOS2). The energy bands used in the 4XMM processing were the same as for the 3XMM catalog.
The following are the basic energy bands:
1: 0.2-0.5 keV
2: 0.5-1.0 keV
3: 1.0-2.0 keV
4: 2.0-4.5 keV
5: 4.5-12.0 keV
All-EPIC values cover the energy range 0.2-12.0 keV.
The full catalog documentation can be found at https://xmmssc.aip.de/.
comparison with the previous stacked catalogs, 4XMM-DR13s through 3XMM-DR7s:
4XMM-DR13s 4XMM-DR12s 4XMM-DR11s 4XMM-DR10s 4XMM-DR9s 3XMM-DR7s
Number of stacks 1,688 1,620 1,475 1,396 1,329 434
Number of observations 9,796 9,355 8,292 7,803 6,604 789
Time span first to last observation Feb 01, 2000 Feb 01, 2000 Feb 03, 2000 Feb 03, 2000 Feb 03, 2000 Feb 20, 2000
-- Nov 29, 2022 -- Dec 04, 2021 -- Dec 17, 2020 -- Dec 14, 2019 -- Nov 13, 2018 -- Apr 02, 2016
Approximate sky coverage (sq. deg.) 650 625 560 540 485 150
Approximate multiply observed sky area(sq. deg) 420 400 350 335 300 100
Total number of sources 401,596 386,043 358,809 335,812 288,191 71,951
Sources with several contributing observations 310,478 298,626 275,440 256,213 218,283 57,665
Multiply observed sources with flag 0 or 1 262,842 252,445 233,542 216,999 191,497 55,450
Multiply observed with a total detection 251,555 241,880 224,178 208,921 181,132 49,935
likelihood of at least six
Multiply observed with a total detection 213,812 205,394 189,556 176,680 153,487 42,077
likelihood of at least ten
Total measurements 1,683,264 1,592,263 1,421,966 1,322,299 1,033,264 216,393
Maximum exposures per source 170 155 140 140 103 69
Maximum observations per source 77 70 65 65 40 23
Maximum on-time per source 2.8 Ms 2.8 Ms 2.8 Ms 2.8 Ms 1.9 Ms 1.3 Ms
The authors find statistically consistent results for the two samples, with the SF described by a power law of the time lag tau, approximately as SF ~ tau0.1. They do not find evidence of the break in the SF, at variance with the case of lower luminosity AGNs. They confirm a strong anti-correlation of the variability with X-ray luminosity, accompanied by a change of the slope of the SF. They also find evidence in support of a weak, intrinsic, average increase of X-ray variability with redshift.
For XMM, the authors used the version of the Serendipitous Source Catalog then available, namely 2XMMi-DR3, the latest incremental update of the second version of the catalogue, with observations made between 2000 February 3 and 2008 October 08; all datasets were publicly available by 2009 October 31, but not all public observations are included in this catalog. The total area of the catalog fields is ~ 814 deg2, but taking account of the substantial overlaps between observations, the net sky area covered independently is ~ 504 deg2. The 2XMMi-DR3 catalogue contains 353,191 detections (above the processing likelihood threshold of 6), related to 262,902 unique X-ray sources, therefore a significant number of sources (41,979) have more than one record within the catalog.
The selected sources were cross-correlated with the DR7 edition of the SDSS Quasar Catalog (Schneider et al. 2010, AJ, 139, 2360) to obtain redshifts and spectral classifications for the sources. The authors used a maximum distance of 1.5 arcseconds, corresponding to the uncertainty in the X-ray positions, resulting in 412 quasars that were observed by XMM-Newton from 2 to 25 epochs each for a total of 1376 observations. The authors refer to these sources as the XMM-Newton sample.
This study reports on the optical identification of the XMS samples, complete to 85 - 95%. At the flux levels sampled by the XMS, the authors find that the X-ray sky is largely dominated by Active Galactic Nuclei. The fraction of stars in soft X-ray selected samples is below 10%, and only a few per cent for hard X-ray selected samples. They find that the fraction of optically obscured objects in the AGN population stays constant at around 15-20% for soft and intermediate band selected X-ray sources, over 2 decades of flux. The fraction of obscured objects amongst the AGN population is larger (~ 35 - 45%) in the hard or ultra-hard selected samples, and constant across a similarly wide flux range. The distribution in X-ray-to-optical flux ratio is a strong function of the selection band, with a larger fraction of sources with high values in hard selected samples. Sources with X-ray-to-optical flux ratios in excess of 10 are dominated by obscured AGN, but with a significant contribution from unobscured AGN.
A sample of X-ray sources detected in 68 XMM-Newton pointed observations was selected for optical multi-fiber spectroscopy. Optical counterparts and corresponding photometry of the X-ray sources were obtained from the SuperCOSMOS Sky Survey. Candidates for spectroscopy were initially selected with magnitudes down to R ~ 21, with preference for X-ray sources having a flux F0.5-4.5keV >= 10-14 erg/s/cm2. Optical spectroscopic observations were made using the Two Degree Field of the Anglo-Australian Telescope, and the resulting spectra were classified based on optical emission lines. The authors have identified through optical spectroscopy 940 X-ray sources over a solid angle Omega ~ 11.8 deg2 of the sky. Source populations in their sample can be summarized as 65% broad-line active galactic nuclei (BLAGN), 16% narrow emission-line galaxies (NELGs), 6% absorption-line galaxies (ALGs) and 13% stars. An active nucleus is also likely to be present in the large majority of the X-ray sources spectroscopically classified as NELGs or ALGs.
Optical images are available for all of the XWAS fields in the SuperCOSMOS Sky Survey (Hambly et al., 2001, MNRAS, 326, 1279).