TheXMM-Newtonsurvey of the Small Magellanic Cloud: The X-ray point-source catalogue

Abstract

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 deg 2 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 × 10 33 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.

High-mass X-ray binaries in the Small Magellanic Cloud

“…With an X-ray luminosity of 3.7 × 10 33 erg s −1 the source was at low luminosity during the Chandra observation (Maravelias et al 2014), and it was not detected by XMM-Newton (Sturm et al 2013c). Maravelias et al (2014) of the marginal line width.…”

“…Description Liu et al (2005) HMXB catalogue of the Magellanic Clouds Coe et al (2005) Optical properties of HMXBs in the SMC Shtykovskiy & Gilfanov (2005) HMXBs in archival XMM-Newton data McGowan et al (2008b) Chandra SMC Wing survey Galache et al (2008) RXTE observations of SMC pulsars McBride et al (2008) Optical spectroscopy of BeXRB pulsars in the SMC New BeXRBs from XMM-Newton observations in Antoniou et al (2009b Optical identification of Chandra sources Antoniou et al (2009a) Optical spectroscopy of BeXRBs in the SMC Laycock et al (2010) Catalogue of SMC sources from deep Chandra observations a Rajoelimanana et al (2011b) Long-term optical variability of HMXB pulsars in the SMC Sturm et al (2013c) XMM-Newton survey of the SMC Coe & Kirk (2015) BeXRB pulsars in the SMC Notes. (a) Includes detections down to two net counts.…”

“…The pulsar was covered by an observation of the XMM-Newton survey of the SMC on October 9−10, 2009 (ObsID 0601210801 with a net exposure of about 23 ks and ∼1000 net source counts; Sturm et al 2013c). A Fourier analysis of the light curve reveals a peak at a frequency consistent with the suggested period.…”

“…We investigated this further using folding techniques based on χ 2 and Rayleigh Z 2 tests (Buccheri et al 1983) and a Bayesian periodic signal detection method (Gregory & Loredo 1996) as described for instance in Coe et al (2012). Sturm et al (2013c) the 1σ error includes a systematic uncertainty of 0.5 . 5…”

“…Confidence class (values 1−6, see Sturm et al (2013c) are given for the 0.2 to 4.5 keV band. To convert them into the 0.2−10 keV band, we multiplied them by a factor of 2.6 assuming a standard power law with photon index 0.9 ) and a column density of 10 21 cm −2 (solar abundance).…”