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The tenth recorded outburst of the recurrent eclipsing nova U Sco was observed simultaneously in X-ray, UV, and optical by XMM-Newton on days 22.9 and 34.9 after the outburst. Two full passages of the companion in front of the nova ejecta were observed, as was the reformation of the accretion disk. On day 22.9, we observed smooth eclipses in UV and optical but deep dips in the X-ray light curve that disappeared by day 34.9, yielding clean eclipses in all bands. X-ray dips can be caused by clumpy absorbing material that intersects the line of sight while moving along highly elliptical trajectories. Cold material from the companion could explain the absence of dips in UV and optical light. The disappearance of X-ray dips before day 34.9 implies significant progress in the formation of the disk. The X-ray spectra contain photospheric continuum emission plus strong emission lines, but no clear absorption lines. Both continuum and emission lines in the X-ray spectra indicate a temperature increase from day 22.9 to day 34.9. We find clear evidence in the spectra and light curves for Thompson scattering of the photospheric emission from the white dwarf. Photospheric absorption lines can be smeared out during scattering in a plasma of fast electrons. We also find spectral signatures of resonant line scattering that lead to the observation of the strong emission lines. Their dominance could be a general phenomenon in high-inclination systems such as Cal 87.

The XMM-Newton Serendipitous Ultraviolet Source Survey (XMM-SUSS) is a catalogue of ultraviolet (UV) sources detected serendipitously by the Optical Monitor (XMM-OM) on board the XMM-Newton observatory. The catalogue contains UV-detected sources collected from 2417 XMM-OM observations in one to six broad-band UV and optical filters, made between 2000 February 24 and 2007 March 29. The primary contents of the catalogue are source positions, magnitudes and fluxes in one to six passbands, and these are accompanied by profile diagnostics and variability statistics. XMM-SUSS is populated by 753 578 UV source detections above a 3σ signal-to-noise ratio threshold limit which relate to 624 049 unique objects. Taking account of substantial overlaps between observations, the net sky area covered is 29-54 deg 2 , depending on UV filter. The magnitude distributions peak at m AB = 20.2, 20.9 and 21.2 in UVW2 (λ eff = 2120 Å), UVM2 (λ eff = 2310 Å) and UVW1 (λ eff = 2910 Å), respectively. More than 10 per cent of the sources have been visited more than once using the same filter during XMM-Newton operation, and >20 per cent of sources are observed more than once per filter during an individual visit. Consequently, the scope for science based on temporal source variability on time-scales of hours to years is broad. By comparison with other astrophysical catalogues we test the accuracy of the source measurements and define the nature of the serendipitous UV XMM-OM source sample. The distributions of source colours in the UV and optical filters are shown together with the expected loci of stars and galaxies, and indicate that sources which are detected in multiple UV bands are predominantly star-forming galaxies and stars of type G or earlier.

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Abstract. -We present a survey of high dispersion UV and optical spectra of Herbig Ae/Be (HAeBe) and related stars. We find accreting, circumstellar gas over the velocity range +100 to +400 km s −1 , and absorption profiles similar to those seen toward β Pic, in 36% of the 33 HAeBe stars with IUE data as well as in 3 non-emission B stars. We also find evidence of accretion in 7 HAeBe stars with optical data only. Line profile variability appears ubiquitous. As a group, the stars with accreting gas signatures have higher v sin i than the stars with outflowing material, and tend to exhibit large amplitude (≥ 1 m ) optical light variations. All of the program stars with polarimetric variations that are anti-correlated with the optical light, previously interpreted as the signature of a dust disk viewed close to equator-on, also show spectral signatures of accreting gas. These data imply that accretion activity in HAeBe stars is preferentially observed when the line of sight transits the circumstellar dust disk. Our data imply that the spectroscopic signatures of accreting circumstellar material seen in β Pic are not unique to that object, but instead are consistent with interpretation of β Pic as a comparatively young A star with its associated circumstellar disk.