2010A&A...515A..25D


Query : 2010A&A...515A..25D

2010A&A...515A..25D - Astronomy and Astrophysics, volume 515, A25-25 (2010/6-1)

The intriguing nature of the high-energy gamma ray source XSS J12270-4859.

DE MARTINO D., FALANGA M., BONNET-BIDAUD J.-M., BELLONI T., MOUCHET M., MASETTI N., ANDRUCHOW I., CELLONE S.A., MUKAI K. and MATT G.

Abstract (from CDS):

The nature of the hard X-ray source XSSJ12270-4859 is still unclear. It was claimed to be a possible magnetic cataclysmic variable of the Intermediate Polar type from its optical spectrum and a possible 860s X-ray periodicity in RXTE data. However, recent observations do not support the latter variability, leaving this X-ray source still unclassified. To investigate its nature we present a broad-band X-ray and gamma ray study of this source based on a recent XMM-Newton observation and archival INTEGRAL and RXTE data. Using the Fermi/LAT 1-year point source catalogue, we tentatively associate XSSJ12270-4859 with 1FGLJ1227.9-4852, a source of high-energy gamma rays with emission up to 10GeV. We further complement the study with UV photometry from XMM-Newton and ground-based optical and near-IR photometry. We have analysed both timing and spectral properties in the gamma rays, X-rays, UV and optical/near-IR bands of XSSJ12270-4859. The X-ray emission is highly variable, showing flares and intensity dips. The flares consist of flare-dip pairs. Flares are detected in both X-rays and the UV range, while the subsequent dips are present only in the X-ray band. Further aperiodic dipping behaviour is observed during X-ray quiescence, but not in the UV. The broad-band 0.2-100keV X-ray/soft gamma ray spectrum is featureless and well described by a power law model with Γ=1.7. The high-energy spectrum from 100MeV to 10GeV is represented by a power law index of 2.45. The luminosity ratio between 0.1-100GeV and 0.2-100keV is ∼0.8, indicating that the GeV emission is a significant component of the total energy output. Furthermore, the X-ray spectrum does not greatly change during flares, quiescence and the dips seen in quiescence. The X-ray spectrum however hardens during the post-flare dips, where a partial covering absorber is also required to fit the spectrum. Optical photometry acquired at different epochs reveals a period of 4.32hr that could be ascribed to the binary orbital period. Near-IR, possibly ellipsoidal, variations are detected. Large amplitude variability on shorter (tens mins) timescales is found to be non-periodic. The observed variability at all wavelengths together with the spectral characteristics strongly favour a low-mass atypical low-luminosity X-ray binary and are against a magnetic cataclysmic variable nature. The association with a Fermi/LAT high-energy gamma ray source further strengths this interpretation.

Abstract Copyright:

Journal keyword(s): binaries: close - stars: individual: XSS J12270-4859 - stars: individual: 1FGLJ1227.9-4852 - X-rays: binaries

Simbad objects: 14

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Number of rows : 14
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 SK 160 HXB 01 17 05.1457288392 -73 26 36.014808156 12.23 13.00 13.15   13.17 O9.7Ia+ 834 0
2 LS I +61 303 HXB 02 40 31.6644419688 +61 13 45.593918580 11.27 11.61 10.75 10.19 9.55 B0Ve 811 2
3 V* UY Vol LXB 07 48 33.71 -67 45 07.7 16.10 17.00 16.9 16.7 17.05 ~ 602 0
4 HD 108433 * 12 27 45.7880605512 -48 56 06.919612440   10.70 9.73     K0/1III 8 0
5 XSS J12270-4859 LXB 12 27 58.7476831464 -48 53 42.824592960           ~ 242 0
6 SUMSS J122820-485537 Rad 12 28 20.990 -48 55 37.30           ~ 2 1
7 AJG 44 Psr 16 17 33.000 -51 02 00.00           ~ 485 3
8 NAME Rapid Burster LXB 17 33 24.61 -33 23 19.8           ~ 400 2
9 3FHL J1746.2-2852 LXB 17 44 33.09 -28 44 27.0           ~ 515 0
10 V* AM Her CV* 18 16 13.2546725112 +49 52 04.759613544   15.124 14.808 13.525   M4.5-5Ve 943 0
11 V* V479 Sct HXB 18 26 15.0561548880 -14 50 54.247274304 12.02 12.23 11.27 11.04   ON6V((f))z 540 2
12 V* V1405 Aql LXB 19 18 47.871 -05 14 17.09 20.90 21.40 21.0     ~ 461 0
13 V* V1521 Cyg HXB 20 32 25.78 +40 57 27.9           WN4/5-6/7 1876 2
14 V* AE Aqr CV* 20 40 09.1598959176 -00 52 15.055595220   12.46 10.40   10.191 K3-5IV/V 652 0

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2022.11.27-17:30:22

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