Aims. Pointed observations with XMM-Newton provide the basis for creating catalogues of X-ray sources detected serendipitously in each field. This paper describes the creation and characteristics of the 2XMM catalogue. Methods. The 2XMM catalogue has been compiled from a new processing of the XMM-Newton EPIC camera data. The main features of the processing pipeline are described in detail. Results. The catalogue, the largest ever made at X-ray wavelengths, contains 246 897 detections drawn from 3491 public XMM-Newton observations over a 7-year interval, which relate to 191 870 unique sources. The catalogue fields cover a sky area of more than 500 deg 2 . The non-overlapping sky area is ∼360 deg 2 (∼1% of the sky) as many regions of the sky are observed more than once by XMM-Newton. The catalogue probes a large sky area at the flux limit where the bulk of the objects that contribute to the X-ray background lie and provides a major resource for generating large, well-defined X-ray selected source samples, studying the X-ray source population and identifying rare object types. The main characteristics of the catalogue are presented, including its photometric and astrometric properties

X-ray spectra of the isolated neutron star RBS1223 obtained with the instruments on board XMM-Newton in December 2001 and January 2003 show deviations from a Planckian energy distribution at energies below 500 eV. The spectra are well fit when a broad, Gaussian-shaped absorption line with σ = 100 eV and centered at an energy of 300 eV is added to an absorbed blackbody model. The resulting equivalent width of the line is −150 eV. However, the spectral resolution at these low energies of the EPIC detectors and the lower statistical quality and restricted energy band of the RGS instruments are not sufficient to exclude even broader lines at energies down to 100 eV or several unresolved lines. The most likely interpretation of the absorption feature is a cyclotron absorption line produced by protons in the magnetic field of the neutron star. In this picture line energies of 100−300 eV yield a magnetic field strength of 2−6×10 13 G for a neutron star with canonical mass and radius. Folding light curves from different energy bands at a period of 10.31 s, which implies a double peaked pulse profile, shows different hardness ratios for the two peaks. This confirms that the true spin period of RBS1223 is twice as long as originally thought and suggests variations in cyclotron absorption with pulse phase. We also propose that changes in photoelectric absorption seen in phase resolved spectra of RX J0720.4−3125 by Cropper et al. (2001), when formally fit with an absorbed blackbody model, are caused instead by cyclotron absorption varying with pulse phase.

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Abstract.We present an analysis of the X-ray light curves of the magnetic cataclysmic variable DP Leo using recently performed XMM−Newton EPIC and archival published and unpublished ROSAT PSPC observations. We combine the timings of the X-ray eclipses with timings derived from archival HST-observations and new optical observations with the photon counting OPTIMA camera. We determine the eclipse length at X-ray wavelengths to be 235 ± 5 s, slightly longer than at ultra-violet wavelengths, where it lasts 225 s. A new orbital ephemeris is derived which connects the more than 120 000 binary cycles covered since 1979. It has a highly significant quadratic term, implying an orbital period change ofṖ = −4.4 × 10 −12 s s −1 , two orders of magnitude larger than being compatible with braking by gravitational radiation only. Over the last twenty years, the optical and X-ray bright phases display a continuous shift with respect to the eclipse center by ∼2.1• yr −1 . Over the last 8.5 years the shift of the X-ray bright phase is ∼2.5• yr −1 . We interpret this as evidence of an asynchronously rotating white dwarf although synchronization oscillations cannot be ruled out completely. If the observed phase shift continues, a fundamental rearrangement of the accretion geometry must occur on a time-scale of some ten years. Applying model atmosphere spectra to optical/UV eclipse light curves, we determine the temperature and mass of the white dwarf, the temperature and size of the optical/UV emitting spot and the distance to DP Leo to be T wd = 13 500 K, M wd 0.6 M , T spot = 32 000 K, A spot 0.1 A wd , and D = 400 pc, respectively. The implied inclination and mass ratio are i = 79.5• and Q = M wd /M 2 = 6.7. DP Leo is marginally detected at eclipse phase in X-rays. The upper limit eclipse flux is consistent with an origin on the late-type secondary, L X 2.5 × 10 29 ergs s −1 (0.20−7.55 keV), at a distance of 400 pc.