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

No abstract

Most ultraluminous X-ray sources 1 (ULXs) display a typical set of properties not seen in Galactic stellar-mass black holes (BHs): higher luminosity (L x > 3 × 10 39 erg s −1 ), unusually soft X-ray components (kT 0.3 keV) and a characteristic downturn 2,3 in their spectra above ≈ 5 keV. Such puzzling properties have been interpreted either as evidence of intermediate-mass BHs 4,5 , or as emission from stellar-mass BHs accreting above their Eddington limit 6,7 , analogous to some Galactic BHs at peak luminosity 8,9 . Recently, a very soft X-ray spectrum has been observed in a rare and transient stellar-mass BH 10 .Here we show that the X-ray source P13 in the galaxy NGC 7793 11 is in a ≈ 64 day period binary and exhibits all three canonical properties of ULXs. By modelling the strong optical and UV modulations due to X-ray heating of the B9Ia donor star, we constrain the BH mass to less than 15 solar masses. Our results demonstrate that in P13, soft thermal emission and spectral curvature are indeed signatures of supercritical accretion. By analogy, ULXs with similar X-ray spectra and luminosities of up to a few 10 40 erg s −1 can be explained by supercritical accretion onto massive stellar BHs.We organised an X-ray, UV and optical spectrophotometric monitoring programme Stacking Swift low state data reveals the source at L X (0.3-10 keV) = 5 ± 1 × 10 37 erg s −1 (90% confidence level), a factor 100 less than in the previously seen bright X-ray state. Scheduled and serendipitous Chandra and XMM-Newton observations carried out in 2011 and 2012 detected the source at the same low X-ray luminosity and will be reported elsewhere.Optical spectra point at a B9I spectral type (Fig. 1). In addition to high-order Balmer absorption lines, the spectrum exhibits Balmer emission up to at least Hγ as well as and V (λ central = 5500Å; ∆ V = 0.5 mag) light-curves and the behaviour of the V -I colour index point at a strong X-ray heating effect of the supergiant star hemisphere facing the compact companion. An X-ray source with a tenth of the nominal X-ray luminosity would brighten the star by only ≈ 0.1 magnitude in V at maximum light and would have basically no effect in the faint X-ray state. Therefore, we conclude that in 2011 part of the companion star photosphere continues to be illuminated by a luminous X-ray source which is however shielded from our view. The Galactic X-ray binary Her X-1 exhibits similar bright/faint X-ray states 18 as well as periodic phase shifts of photometric maxima 19 . By analogy, we suggest that a tilted precessing accretion disk is at the origin of both the X-ray bright & faint states and of the phase jitter of optical maximum light.In order to constrain the geometry and dynamics of the system we simultaneously fitted the V and UVOT u light-curves using the Eclipsing Light Curve code 20 (ELC). We tested four X-ray luminosity levels ranging from 0.7 up to 2 times a nominal value of 4.2 × 10 39 erg s −1 (derived from the diskbb + comptt fit to the Chandra spectrum extrapolated to the 0.3-20 keV r...

Black-hole accretion states near or above the Eddington luminosity (the point at which radiation force outwards overcomes gravity) are still poorly known because of the rarity of such sources. Ultraluminous X-ray sources are the most luminous class of black hole (L(X) approximately 10(40) erg s(-1)) located outside the nuclei of active galaxies. They are likely to be accreting at super-Eddington rates, if they are powered by black holes with masses less than 100 solar masses. They are often associated with shock-ionized nebulae, though with no evidence of collimated jets. Microquasars with steady jets are much less luminous. Here we report that the large nebula S26 (ref. 4) in the nearby galaxy NGC 7793 is powered by a black hole with a pair of collimated jets. It is similar to the famous Galactic source SS433 (ref. 5), but twice as large and a few times more powerful. We determine a mechanical power of around a few 10(40) erg s(-1). The jets therefore seem 10(4) times more energetic than the X-ray emission from the core. S26 has the structure of a Fanaroff-Riley type II (FRII-type) active galaxy: X-ray and optical core, X-ray hot spots, radio lobes and an optical and X-ray cocoon. It is a microquasar where most of the jet power is dissipated in thermal particles in the lobes rather than relativistic electrons.

Context. Thanks to the large collecting area (3 × ∼1500 cm 2 at 1.5 keV) and wide field of view (30 across in full field mode) of the X-ray cameras on board the European Space Agency X-ray observatory XMM-Newton, each individual pointing can result in the detection of up to several hundred X-ray sources, most of which are newly discovered objects. Since XMM-Newton has now been in orbit for more than 15 yr, hundreds of thousands of sources have been detected. Aims. Recently, many improvements in the XMM-Newton data reduction algorithms have been made. These include enhanced source characterisation and reduced spurious source detections, refined astrometric precision of sources, greater net sensitivity for source detection, and the extraction of spectra and time series for fainter sources, both with better signal-to-noise. Thanks to these enhancements, the quality of the catalogue products has been much improved over earlier catalogues. Furthermore, almost 50% more observations are in the public domain compared to 2XMMi-DR3, allowing the XMM-Newton Survey Science Centre to produce a much larger and better quality X-ray source catalogue. Methods. The XMM-Newton Survey Science Centre has developed a pipeline to reduce the XMM-Newton data automatically. Using the latest version of this pipeline, along with better calibration, a new version of the catalogue has been produced, using XMM-Newton X-ray observations made public on or before 2013 December 31. Manual screening of all of the X-ray detections ensures the highest data quality. This catalogue is known as 3XMM. Results. In the latest release of the 3XMM catalogue, 3XMM-DR5, there are 565 962 X-ray detections comprising 396 910 unique X-ray sources. Spectra and lightcurves are provided for the 133 000 brightest sources. For all detections, the positions on the sky, a measure of the quality of the detection, and an evaluation of the X-ray variability is provided, along with the fluxes and count rates in 7 X-ray energy bands, the total 0.2-12 keV band counts, and four hardness ratios. With the aim of identifying the detections, a cross correlation with 228 catalogues of sources detected in all wavebands is also provided for each X-ray detection. Conclusions. 3XMM-DR5 is the largest X-ray source catalogue ever produced. Thanks to the large array of data products associated with each detection and each source, it is an excellent resource for finding new and extreme objects.Key words. catalogs -astronomical databases: miscellaneous -surveys -X-rays: general Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.The catalogue is available at http://cdsarc.u-strasbg.fr/ viz-bin/VizieR?-meta.foot&-source=IX/46

Abstract. ESO 4 m class telescope and VLT deep imaging of the isolated neutron star RX J0720.4-3125 reveals a proper motion of µ = 97 ± 12 mas/yr and a blue U − B color index. We show that a neutron star atmosphere model modified to account for a limited amount of hydrogen on the star's surface can well represent both the optical and X-ray data without invoking any additional thermal component. The large proper motion almost completely excludes the possibility that accretion from the interstellar medium is the powering mechanism of the X-ray emission. It also implies that the proposed spin down is entirely due to magnetic dipole losses. RX J0720.4-3125 is thus very likely a middle aged cooling neutron star. Its overall properties are quite similar to some of the long period radio pulsars recently discovered, giving further support to the idea that RX J0720.4-3125 may be a pulsar whose narrow radio beam does not cross the Earth.

M. Feroci et al.Abstract High-time-resolution X-ray observations of compact objects provide direct access to strong-field gravity, to the equation of state of ultradense matter and to black hole masses and spins. A 10 m 2 -class instrument in combination with good spectral resolution is required to exploit the relevant diagnostics and answer two of the fundamental questions of the European Space Agency (ESA) Cosmic Vision Theme "Matter under extreme conditions", namely: does matter orbiting close to the event horizon follow the predictions of general relativity? What is the equation of state of matter in neutron stars? The Large Observatory For X-ray Timing (LOFT), selected by ESA as one of the four Cosmic Vision M3 candidate missions to undergo an assessment phase, will revolutionise the study of collapsed objects in our galaxy and of the brightest supermassive black holes in active galactic nuclei. Thanks to an innovative design and the development of large-area monolithic silicon drift detectors, the Large Area Detector (LAD) on board LOFT will achieve an effective area of ∼12 m 2 (more than an order of magnitude larger than any spaceborne predecessor) in the 2-30 keV range (up to 50 keV in expanded mode), yet still fits a conventional platform and small/medium-class launcher. With this large area and a spectral resolution of <260 eV, LOFT will yield unprecedented information on strongly curved spacetimes and matter under extreme conditions of pressure and magnetic field strength.

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.