CHANSEXAGN Catalog
The authors compare the relative merits of active galactic nuclei (AGN)
selection at X-ray and mid-infrared wavelengths using data from moderately
deep fields observed by both Chandra and Spitzer. The X-ray-selected AGN
sample and associated photometric and spectroscopic optical follow-up are
drawn from a subset of fields studied as part of the Serendipitous
Extragalactic X-ray Source Identification (SEXSI) program. Mid-infrared data
in these fields are derived from targeted and archival Spitzer imaging, and
mid-infrared AGN selection is accomplished primarily through application of
the Infrared Array Camera (IRAC) color-color AGN "wedge" selection technique.
Nearly all X-ray sources in these fields which exhibit clear spectroscopic
signatures of AGN activity have mid-infrared colors consistent with IRAC AGN
selection. These are predominantly the most luminous X-ray sources. X-ray
sources that lack high-ionization and/or broad lines in their optical spectra
are far less likely to be selected as AGNs by mid-infrared color selection
techniques. The fraction of X-ray sources identified as AGN in the
mid-infrared increases monotonically as the X-ray luminosity increases.
Conversely, only 22% of mid-infrared-selected AGN are detected at X-ray
energies in the moderately deep (t_exp_n~ 100 ks) SEXSI Chandra data.
The authors have expanded the multi-wavelength data available for six SEXSI
fields by obtaining Spitzer imaging observations. All six fields have deep
Chandra X-ray images, optical imaging, and extensive, deep optical
spectroscopy -- all of which has been published in Harrison et al. (2003,
ApJ, 596, 944), Eckart et al. (2005, ApJS, 156, 35), and Eckart et al. (2006,
ApJS, 165, 19). The authors obtained mid-infrared imaging through both
archival and targeted Spitzer programs which include imaging at 3.6, 4.5,
5.8, and 8 micron (um) from IRAC (PID 00017, 00064, 20694 and 20808), and
imaging at 24 um from MIPS (PID 20808 and 00083). This table contains mid-IR
photometric data for 290 hard X-ray-selected SEXSI sources. Each of the four
IRAC catalogs as well as the MIPS catalog was individually matched to the
SEXSI X-ray source positions using a 2.5 arcseconds search radius. To
calculate a false match rate, the authors shifted the X-ray source catalog by
1' and matched to the IRAC and MIPS catalogs; this entire procedure was
repeated 6 times using different 1' shifts. The resulting false match rates
were 10.1% (3.6 um), 7.2% (4.5 um), 3.7% (5.8 um), 2.6% (8.0 um), 1% (24 um),
and <1% for four-band-detected IRAC sources.
MYSTIXIRES Catalog
The Massive Young Star-Forming Complex Study in Infrared and X-rays (MYStIX)
project provides a comparative study of 20 Galactic massive star-forming
complexes with distances between 0.4 and 3.6 kpc. Probable stellar members in
each target complex are identified using X-ray and/or infrared data via two
pathways: (1) X-ray detections of young/massive stars with coronal
activity/strong winds or (2) infrared excess (IRE) selection of young stellar
objects (YSOs) with circumstellar disks and/or protostellar envelopes. In
this particular study, the authors present the methodology for the second
pathway using Spitzer/IRAC, 2MASS, and UKIRT imaging and photometry. Although
IRE selection of YSOs is well-trodden territory, MYStIX presents unique
challenges. The target complexes range from relatively nearby clouds in
uncrowded fields located toward the outer Galaxy (e.g., NGC 2264, the Flame
Nebula) to more distant, massive complexes situated along complicated, inner
Galaxy sightlines (e.g., NGC 6357, M 17). The authors combine IR spectral
energy distribution (SED) fitting with IR color cuts and spatial clustering
analysis to identify IRE sources and to isolate probable YSO members in each
MYStIX target field from the myriad types of contaminating sources that can
resemble YSOs: extragalactic sources, evolved stars, nebular knots, and even
unassociated foreground/background YSOs. Applying their methodology
consistently across 18 of the target complexes, they produce the MYStIX IRE
Source (MIRES) Catalog comprising 20,719 sources, including 8,686 probable
stellar members of the MYStIX target complexes. They also classify the SEDs
of 9,365 IR counterparts to MYStIX X-ray sources to assist the first pathway,
the identification of X-ray-detected stellar members.
The MYStIX project, described by Feigelson et al. (2013, ApJS, 209, 26),
provides a comprehensive, parallel study of 20 Galactic massive star-forming
regions. The basic input data for the MIRES Catalog were near-IR (NIR) and
mid-IR (MIR) photometric catalogs. The authors also used NIR and MIR images
and mosaics for visualizing the point-source populations with respect to
various nebular structures. They provide high-level descriptions of each
input catalog in section 2 of the reference paper.
This table contains the MYStIX IRE Source (MIRES) Catalog comprising IR data
on 20,719 sources, including 8,686 probable stellar members of the MYStIX
target complexes, viz., massive star-forming regions (MSFRs), which was given
in Table 2 of the reference paper. It does not include the IR data of the
above-mentioned 9,365 IR counterparts to MYStIX X-ray sources (the SED
Classification of IR Counterparts to MYStIX X-ray sources (SCIM-X Catalog)
that were listed in Table 7 of the reference paper.
MYSTIXMIDI Catalog
Spitzer IRAC observations and stellar photometric catalogs are presented for
the Massive Young star-forming complex Study in the Infrared and X-ray
(MYStIX). MYStIX is a multi-wavelength census of young stellar members of 20
nearby (distances < 4 kpc), Galactic, star-forming regions (SFRs) that
contain at least one O-type star. All regions have data available from the
Spitzer Space Telescope consisting of GLIMPSE or other published catalogs for
11 regions and results of the authors' own photometric analysis of archival
data for the remaining 9 regions. The authors also reduced the GLIMPSE data
for the W 3 SFR using the aperture photometry method in order to compare the
results obtained using the two methods (see Section 3.4.2 of the reference
paper).
The reference paper seeks to construct deep and reliable catalogs of sources
from the Spitzer images. Mid-infrared study of these regions faces challenges
of crowding and high nebulosity. These new catalogs typically contain fainter
sources than existing Spitzer studies, which improves the match rate to
Chandra X-ray sources that are likely to be young stars, but increases the
possibility of spurious point-source detections, especially peaks in the
nebulosity. IRAC color-color diagrams help distinguish spurious detections of
nebular polycyclic aromatic hydrocarbon (PAH) emission from the infrared
excess associated with dusty disks around young stars. The distributions of
sources on the mid-infrared color-magnitude and color-color diagrams reflect
differences between MYStIX regions, including astrophysical effects such as
stellar ages and disk evolution.
The GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire) Survey
is a Legacy Science Program of the Spitzer Space Telescope to study star
formation in the disk of the Milky Way Galaxy. It contains six MYStIX regions
- the Lagoon Nebula, the Trifid Nebula, NGC 6334, the Eagle Nebula, M 17, and
NGC 6357 - within the 2-degree wide strip along the Galactic equator (GLIMPSE
I and II data releases). Furthermore, Spitzer images and photometry for RCW
38 and NGC 3576 come from the Vela-Carina survey (Majewski et al. 2007,
Spitzer Proposal 40791), using a similar observing strategy with mosaicking
and photometric analysis as performed with the GLIMPSE pipeline.
The authors obtained publicly available raw IRAC images from the Spitzer
Heritage Archive for nine MYStIX regions without GLIMPSE coverage. The target
list and details of the Astronomical Observation Requests (AORs) are provided
in Table 1 of the reference paper. The camera spatial resolutions are FWHM =
1.6" to 1.9" from 3.6 to 8.0um.
This table contains the combined IRAC source lists from the GLIMPSE
photometry of W 3 and the aperture photometry of the 9 SFRs listed in Table 4,
part 1 of the reference paper.
RCW38YSO Catalog
This table contains some of the results from a study of the structure of the
high-mass star-forming region RCW 38 and the spatial distribution of its
young stellar population. Spitzer Infrared Array Camera (IRAC) photometry
(3-8 micron) is combined with Two Micron All Sky Survey (2MASS) near-IR data
to identify young stellar objects (YSOs) by IR-excess emission from their
circumstellar material. Chandra X-ray data are used to identify class III
pre-main-sequence stars lacking circumstellar material. The authors identify
624 YSOs: 23 class 0/I and 90 flat spectrum (FS) protostars, 437 class II
stars, and 74 class III stars. They also identify 29 (27 new) O star
candidates over the IRAC field. Seventy-two stars exhibit IR-variability,
including 7 class 0/I and 12 flat spectrum YSOs. A further 177 tentative
candidates are identified by their location in the IRAC [3.6] versus
[3.6]-[5.8] color-magnitude diagram. The authors find strong evidence of
subclustering in the region. Three subclusters were identified surrounding
the central cluster, with massive and variable stars in each subcluster. The
central region shows evidence of distinct spatial distributions of the
protostars and pre-main-sequence stars. A previously detected IR cluster,
DB2001_Obj36, has been established as a subcluster of RCW 38. This suggests
that star formation in RCW 38 occurs over a more extended area than
previously thought. The gas-to-dust ratio is examined using the X-ray derived
hydrogen column density, NH and the K-band extinction, and found to be
consistent with the diffuse interstellar medium, in contrast with Serpens and
NGC 1333. The authors posit that the high photoionizing flux of massive stars
in RCW 38 affects the agglomeration of the dust grains.
This table contains the list of 624 young stellar objects (given in Tables 3
and 4 of the reference paper) found among the Spitzer sources in the field of
RCW 38 using the two selection techniques described in Section 3 of the
reference paper: (1) selection of stars with IR excesses in IR color-color
diagrams, and (2) identification of X-ray luminous YSOs by comparing X-ray
sources with IR detections. The latter technique was used to identify Type
III YSOs lacking emission from a dusty disk. This table does NOT contain (i)
the 177 candidate YSOs listed in Table 5 of the reference paper which were
identified using the [3.6] versus [3.6] - [5.8] color-magnitude diagram,
since contamination removal methods could not be utilized for these objects,
(ii) the 24 candidate variable YSOs listed in Table 6 of the reference paper,
nor (iii) 21 of the 29 candidate O-star cluster members which were listed in
table 7 of the reference paper.
SPITZMASTR Catalog
This database table contains the Spitzer Space Telescope (SST) log of
executed and scheduled observations, and is updated on a weekly basis.
Spitzer is the fourth and final element in NASA's family of Great
Observatories and represents an important scientific and technical bridge to
NASA's Astronomical Search for Origins program. The SST Observatory carries
an 85-cm cryogenic telescope and 3 cryogenically cooled science instruments
capable of performing imaging and spectroscopy in the 3.6 to 160 micron (µm)
range. Spitzer was launched on a Delta 7920H from Cape Canaveral into an
Earth-trailing heliocentric orbit in August 2003. While the Spitzer cryogenic
lifetime requirements are 2.5 years, current estimates indicate that
http://ssc.spitzer.caltech.edu/spitzermission/.
The purpose of this HEASARC table is to help users, particularly those in the
high-energy astronomy community, learn about which targets Spitzer has
observed or will shortly observe. This table does not at this time have links
from table entries to Spitzer data products. Once a particular Spitzer
dataset of interest is identified, the SSC Archives/Analysis web page at
http://ssc.spitzer.caltech.edu/archanaly/ should be used to access the
dataset.
SPORIABYSO Catalog
This table contains results from a survey of the Orion A and B
molecular clouds undertaken with the IRAC and MIPS instruments on board
Spitzer. In total, five distinct fields were mapped, covering 9 deg2 in five
mid-IR bands spanning 3 - 24 microns (um). The survey includes the Orion Nebula
Cluster, the Lynds 1641, 1630, and 1622 dark clouds, and the NGC 2023, 2024,
2068, and 2071 nebulae. These data are merged with the Two Micron All Sky
Survey point source catalog to generate a catalog of eight-band photometry. The
authors identify 3479 dusty young stellar objects (YSOs) in the Orion molecular
clouds by searching for point sources with mid-IR colors indicative of
reprocessed light from dusty disks or in-falling envelopes. The YSOs are
subsequently classified on the basis of their mid-IR colors and their spatial
distributions are presented. The authors classify 2991 of the YSOs as
pre-main-sequence stars with disks and 488 as likely protostars. Most of the
sources were observed with IRAC in two to three epochs over six months; the
authors search for variability between the epochs by looking for correlated
variability in the 3.6 and 4.5 um bands. They find that 50% of the dusty YSOs
show variability. The variations are typically small (~ 0.2 mag) with the
protostars showing a higher incidence of variability and larger variations.
The observed correlations between the 3.6, 4.5, 5.8, and 8 um variability
suggests that we are observing variations in the heating of the inner disk due
to changes in the accretion luminosity or rotating accretion hot spots.
SWIRECXO Catalog
This table contains results from deep combined observations with
Spitzer and Chandra of the Spitzer Wide-Area Infrared Extragalactic Survey
(SWIRE) in the ELAIS N1 region. This survey was used to investigate the nature
of the faint X-ray and IR sources in common, to identify active galactic
nucleus (AGN)/starburst diagnostics, and to study the sources of the X-ray
and cosmic infrared backgrounds (XRB and CIRB). In the 17' x 17' area of the
Chandra ACIS-I image there were approximately 3400 SWIRE near-IR sources with
4-sigma detections in at least two Infrared Array Camera (IRAC) bands and 988
sources detected at 24 micron (um) with the Multiband Imaging Photometer
(MIPS) brighter than a 24-um flux S_24 ~ 0.1 mJy. Of these, 102 IRAC and 59
MIPS sources have Chandra counterparts, out of a total of 122 X-ray sources
present in the area with 0.5 - 8 keV flux > 10-15 erg cm^-2 s^-1.
The SWIRE ELAIS N1 field was imaged by the IRAC multiband camera on Spitzer in
2004 January and with MIPS in early 2004 February. The observations were
centered at the position (16h 00m, +59d 01'). The X-ray observations were
taken as part of the ELAIS Deep X-ray Survey (EDXS) and are described in
detail in Manners et al. (2003, MNRAS, 343, 293). For this analysis, the
Chandra Advanced CCD Imaging Spectrometer (ACIS) observation of 75 ks centered
on (16h 10m 20.11s, +54d 33' 22.3") (J2000.0) in the ELAIS N1 region. The aim
point was focused on the ACIS-I chips, which consist of four CCDs arranged in
a 2 x 2 array covering an area of 16.9' x 16.9' (286 square arcmin). Bad pixels
and columns were removed, and data were filtered to eliminate high background
times (due to strong solar flares), leaving 71.5 ks of good data after
filtering. Counts-to-photon calibration assumed a standard power-law model
spectrum with photon index Gamma = 1.7.
Sources were detected to flux levels of 2.3 x 10^-15 erg s^-1 cm^-2 in
the 0.5 - 8 keV band, 9.4 x 10^-16 erg s^-1 cm^-2 in the 0.5 - 2 keV band, and
5.2 x 10^-15 erg s^-1 cm^-2 in the 2 - 8 keV band. Sources are detectable to
these flux limits over 90% of the nominal survey area. For this analysis,
the authors used sources detected in the full band of ACIS-I only, of which
there are 122 in the N1 region. Of the 102 sources in common between Chandra
and SWIRE, 83 have significant detections in the separate soft X-ray band
(0.5 - 2 keV) and 64 are detected in the hard (2 - 8 keV) band.
A simple near-neighbor search was performed to cross-correlate the Spitzer and
Chandra source catalogs within the Chandra ACIS-I chip image, using a d = 5"
search radius (roughly the quadratic sum of the astrometric errors). All
together, the authors found reliably associated counterparts for 102 of the
122 Chandra sources (84% in total). The vast majority of these were detected
with the IRAC channels 1 and 2 (3.6 and 4.5 um): 100 of the 122 Chandra
sources in each case. As many as 59 Chandra objects are reliably associated
with MIPS 24 um sources (all of them having IRAC counterparts), and just 1 had
a MIPS 70 um counterpart. Of the 102 Spitzer-identified Chandra sources, three
turned out to correspond to Galactic stars on the basis of their position on
color-magnitude plots and optical morphology and were excluded from the
subsequent analysis (and this table).
SWIRELHCXO Catalog
The authors have carried out a moderate-depth (70 ks), contiguous 0.7
square degrees Chandra survey in the Lockman Hole Field of the Spitzer/SWIRE
Legacy Survey coincident with a completed, ultra-deep VLA survey with deep
optical and near-infrared imaging in-hand. The primary motivation is to
distinguish starburst galaxies and active galactic nuclei (AGNs), including
the significant, highly obscured (log NH > 23 cm-2) subset. Chandra has
detected 775 X-ray sources to a limiting broadband (0.3 - 8 keV) flux of ~4
x 10-16 erg cm-2 s-1. This table contains the X-ray catalog, fluxes,
hardness ratios, and multi-wavelength fluxes. The log N versus log S agrees
with those of previous surveys covering similar flux ranges. The Chandra and
Spitzer flux limits are well matched: 771 (99%) of the X-ray sources have
infrared (IR) or optical counterparts, and 333 have MIPS 24-micron detections.
There are four optical-only X-ray sources and four with no visible optical/IR
counterpart. The very deep (~2.7 microJansky rms) VLA data yield 251 (>
4 sigma) radio counterparts, 44% of the X-ray sources in the field. The
authors confirm that the tendency for lower X-ray flux sources to be harder
is primarily due to absorption. As expected, there is no correlation between
observed IR and X-ray fluxes. Optically bright, type 1, and red AGNs lie
in distinct regions of the IR versus X-ray flux plots, demonstrating the
wide range of spectral energy distributions in this sample and providing
the potential for classification/source selection. Many optically bright
sources, which lie outside the AGN region in the optical versus X-ray plots
(fr/fx > 10), lie inside the region predicted for red AGNs in IR versus
X-ray plots, consistent with the presence of an active nucleus. More than
40% of the X-ray sources in the VLA field are radio-loud using the classical
definition of RL. The majority of these are red and relatively faint in the
optical so that the use of RL to select those AGNs with the strongest radio
emission becomes questionable. Using the 24-micron to radio flux ratio (q24)
instead results in 13 of the 147 AGNs with sufficient data being classified
as radio-loud, in good agreement with the ~10% expected for broad-lined AGNs
based on optical surveys. The authors conclude that q24 is a more reliable
indicator of radio-loudness. Use of RL should be confined to the optically
selected type 1 AGN.
