We observed a newly discovered X-ray source int X-rays and in the optical to confirm its nature as a high mass X-ray binary. We analysed XMM-Newton and Swift X-ray data, along with optical observations with the ESO Faint Object Spectrograph, to investigate the spectral and temporal characteristics of the source. The XMM-Newton data show coherent X-ray pulsations while the spectra can be modelled with a combination of a power law plus a black body component. We performed optical spectroscopy from which we classify the companion star as a B0-1.5Ve star. The X-ray pulsations, the long-term x-ray variability and the properties of the optical counterpart confirms the the x-ray source as a new Be/X-ray binary pulsar in the LMC.

Nearby galaxies are well suited for investigating X-ray source populations in different environments than in our own Galaxy. Moreover, sources in these galaxies have well determined distances and are less absorbed than sources in the galactic plane. The Large (LMC) and the Small (SMC) Magellanic Clouds (MC) are the nearest gas-rich star-forming galaxies and their gravitational interactions are believed to have tidally triggered recent bursts of star formation. The XMM-Newton large program for the SMC, together with archival observations covers an area of 5.5 square degrees and has already produced significant results. The XMM-Newton large program for the LMC has just been completed and has covered an even bigger area of about 10 square degrees. Both surveys reach a limiting luminosity of 1032 erg/s and provide a unique data set for X-ray source population studies. The two surveys have allowed us to derive hardness ratios for the point sources and conduct spectral classification. For the brightest sources, we performed spectral and timing analysis. By complementing these results with surveys at other wavelengths we have managed to extend our understanding of the nature of individual sources as well as providing complete data-sets of X-ray source populations (X-ray Binaries, supersoft sources, supernova remnants, background active galactic nuclei and foreground galactic sources). From the classification of the sources we have constructed luminosity functions which will allow as to compare X-ray populations in the different environments that the MCs provide. Here, we present an overview of these two surveys together with the highlights of the most interesting sources that they have produced so far (e.g. Be/X-ray binaries).

In a monitoring observation of the central region of the Andromeda Galaxy (M 31) with the Ultra-violet/Optical Telescope (UVOT) on board the Swift satellite (ObsID 00035336102, starting 2013-05-27.15 UT), we detected a new UV transient (UVW1 filter, 181-321 nm). The source is located at RA 00h 42m 55.62s, Dec +41d 14' 12.3" (± 0.5", J2000, 90% confidence level). The following table lists the Swift ObsID, the MJD at the beginning of the exposure, UVW1 magnitudes (Vega system), and 1σ statistical uncertainties.

We report a new high-mass X-ray binary (HMXB), found in a Swift observation performed on 2013 October 11 as part of the monitoring of the nova LMC2012 (ObsId: 00049549004). The Swift/XRT count rate was 0.023±0.008 cts s-1, corresponding to a flux of 1.6×10-12 erg cm-2 s-1 (0.3-10 keV) and an unabsorbed luminosity of 5.1×1035 erg s-1 for LMC distance (50 kpc).

A Swift observation performed on 2013 January 13 as part of the LMC UV survey (PI: S. Immler) detected the high-mass X-ray binary candidate RX J0520.5-6932 in a moderately bright X-ray outburst. Assuming a power-law spectrum with a photon index of 0.9 and absorption of 1021 cm-2, we derive a 0.2-12 keV flux of 1.67 × 10-12 erg s-1 cm-2. This flux is ~25 times higher than measured during a recent XMM-Newton observation (see below).

A series of observations performed with Swift/XRT (Target ID 33042) in the SMC detected a relatively bright X-ray source at the edge of the field of view. The source is consistent with XMMU J010429.4-723136. It is classified as a high-mass X-ray binary (HMXB) candidate in the XMM-Newton point-source catalogue of the SMC (Sturm et al.

RX J0520.5-6932 is a recently confirmed Be/X-ray binary system in the LMC (see ATel #4748).

Aims: We observed the newly discovered X-ray source Swift J053041.9-665426in the X-ray and optical regime to confirm its proposed nature as a high mass X-ray binary. Methods: We obtained XMM-Newton and Swift X-ray data, along with optical observations with the ESO Faint Object Spectrograph, to investigate the spectral and temporal characteristics of Swift J053041.9-665426. Results: The XMM-Newton data show coherent X-ray pulsations with a period of 28.77521(10) s (1σ). The X-ray spectrum can be modelled by an absorbed power law with photon index within the range 0.76 to 0.87. The addition of a black body component increases the quality of the fit but also leads to strong dependences of the photon index, black-body temperature and absorption column density. We identified the only optical counterpart within the error circle of XMM-Newton at an angular distance of ~0.8'', which is 2MASS J05304215-6654303. We performed optical spectroscopy from which we classify the companion as a B0-1.5Ve star. Conclusions: The X-ray pulsations and long-term variability, as well as the properties of the optical counterpart, confirm that Swift J053041.9-665426 is a new Be/X-ray binary pulsar in the Large Magellanic Cloud. Based on observations with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member states and the USA (NASA).