The XMM-Newton survey of the Small Magellanic Cloud: The X-ray point-source catalogue
Résumé
Context. Local-Group galaxies provide access to samples of X-ray source
populations of whole galaxies. The XMM-Newton survey of the Small
Magellanic Cloud (SMC) completely covers the bar and eastern wing with a 5.6
deg2 area in the (0.2−12.0) keV band. Aims. To characterise the X-ray sources in the SMC field, we created a
catalogue of point sources and sources with moderate extent. Sources with high extent
(≥40′′) have been presented in a companion paper. Methods. We searched for point sources in the EPIC images using
sliding-box and maximum-likelihood techniques and classified the sources using hardness
ratios, X-ray variability, and their multi-wavelength properties. Results. The catalogue comprises 3053 unique X-ray sources with a median
position uncertainty of 1.3′′ down to a flux limit for point sources of
~10-14 erg cm-2 s-1 in the (0.2−4.5) keV band,
corresponding to 5 × 1033 erg s-1 for sources in the SMC. We discuss
statistical properties, like the spatial distribution, X-ray colour diagrams, luminosity
functions, and time variability. We identified 49 SMC high-mass X-ray binaries (HMXB),
four super-soft X-ray sources (SSS), 34 foreground stars, and 72 active galactic nuclei
(AGN) behind the SMC. In addition, we found candidates for SMC HMXBs (45) and faint SSSs
(8) as well as AGN (2092) and galaxy clusters (13). Conclusions. We present the most up-to-date catalogue of the X-ray
source population in the SMC field. In particular, the known population of X-ray binaries
is greatly increased. We find that the bright-end slope of the luminosity function of
Be/X-ray binaries significantly deviates from the expected universal high-mass X-ray
binary luminosity function.
Origine : Publication financée par une institution
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