1. The X-ray Universe 2005 26-30 September 2005, El Escorial, Madrid, Spain The XMM-Newton Slew Survey XMM-Newton Slew 1 (XMMSL1) Fig 1. Slew observation performed with the EPIC- pn camera. Current status Images and exposure maps have been created and source searched for 220 slews giving: 4177 sources in the total band 4177 sources in the total band 2750 sources in the soft band 2750 sources in the soft band 844 sources in the hard band 844 sources in the hard band Positional accuracy: 8 arcsec Source density: ~0.65 sources per square degree Sky coverage: ~6300 square degrees (~15% of the sky) Objective: issue of the first slew source catalogue (XMMSL1) by the end of 2005 and provide an upper limit server in 2006 Attitude reconstruction The attitude reconstruction is crucial in determination of source coordinates and is differently performed in slew observations with respect to the pointed ones where the AHF is used. The optimal attitude file for reconstructing the astrometry during slew observations is the Raw Attitude File (RAF) subtracted by 0.75 seconds from every entry, timing error that is due to a delay of the star tracker CCDs. Fig. 3. Comparison of data processing with the different attitude files used for astrometry reconstruction for the slew source XMMSL1 05:28:45.0-65:26:52. Right images: detected slew source in the total band. Left images: position of the slew source overplotting the corresponding optical counterpart. Top panel: source detected with the AHF as attitude file, the shift between the optical and the slew position is evidenced.. Bottom panel: corrected slew source position using the modified RAF for the attitude reconstruction. We can clearly see the difference between both processing and the improvement with the new attitude reconstruction. Spurious detections Systematic effects in the instrument and detection software lead to a number of spurious detections that are being flagged in different categories: False detection False detection Within extended source Within extended source Within halo of bright source Within halo of bright source Position suspect Position suspect Source near edge Source near edge Detector flash Detector flash Observations and data analysis Processing challenges The XMM-Newton satellite is the most sensitive X-ray observatory flown to date due to the great collecting area of its mirrors coupled with the high quantum efficiency of the EPIC detectors. It performs slewing manoeuvers between observation targets with the EPIC cameras open and the other instruments closed, operating with the observing mode set to the one of the previous pointed observation and the medium filter in place. Slew observations from the EPIC-pn camera in FF, eFF and LW provide data, resulting in 15 seconds on-source time, which can be used to give a uniform survey of the X-ray sky. Only data from EPIC-pn slew observations are used for the processing due to the faster readout in their observing modes and its high effective area with respect to the EPIC- MOS cameras. The low background of the observations (average ~0.1c/arcmin 2 ) and the tight PSF give good sensitivity to detect extended sources. Some high background observations that were performed at times of enhanced solar activity were rejected for the processing. Slew observations have to be subdivided into 1 square degree images, then sky positions are recalculated. Source search using a near standard pipeline eboxdetect/emldetect tuned for ~zero background. Three different energy bands are source searched independently: total band (0.2–0.5 keV) soft band (0.2–2 keV) hard band (2–12 keV) Fig 5. Aitoff projection of the distribution of all XMMSL1 sources obtained during slew observations. Catalogue correlation and positional accuracy Source correlation of 2178 no-extended sources with det_ml>10.0 RASS correlation (Fig 7 left) ~56% of the slew sources have RASS counterpart within 60 arcsec 68% of the sources lies within 15 arcsec SIMBAD correlation (Fig 7 right) 68% of the sources lies within 8 arcsec Detected sources A great variety of sources have been detected during slews, including AGN, QSO, galaxies, cluster of galaxies, LMXB and SNR among others. We can study object variability from sources detected in more than one slew or count rate ratios between the XMM slew sources and RASS sources. ESAC The XMM-Newton Slew Survey Abstract Fig 2. Plots of the radial profile (solid line ) of the detected source (this source is showed at the corner of the picture as an optical image and X-ray contours overplotted) and the PSF (dashed line). Left: the radial profile fits very well the PSF so the source can be classified as point-like. Right: for a extended source the radial profile does not fit the PSF. Fig 4. Subimage of the slew observation in revolution 0689. The real slew source is white circled and corresponding to 1A 1743-322. Spurious detections within the halo of this bright source are shown in light blue. Fig 7. Histogram of the distribution of the angular separation in arcsec derived from correlations of the slew source positions. Left: correlation with the RASS catalogue, 68% of the matches lie within 15 arcsec. Right: correlation with the SIMBAD database, 68% of the matches lie within 8 arcsec. Flux detection limits: sensitivity of the survey Soft X-ray band detection limit: 6(4.5) 10 -13 ergs s -1 cm -2 close to ROSAT BS catalogue Hard X-ray band detection limit deepest ever: 4(3) 10 -12 ergs s -1 cm -2 >10× deeper than EXOSAT, HEAO-1 ~2.5× deeper than RXTE (only has 1° positional accuracy) Fig.6. Counterpart galaxies of two slew sources derived from the SDSS correlation. Fig 8. Flux limits of the X-ray large area surveys. The fluxes for the XMM-slew survey have been calculated for a source with DET_ML=10 and passing through the centre of the field of view. These fluxes were derived from count rates based on energy conversion factors assuming an absorbed power-law model with N H =3.0·10 20 cm 2 and slope 1.7 M.P. Esquej a, R.D. Saxton a, A.M. Read c, B. Altieri a, M.J. Freyberg b, D. Bermejo a, V. Lazaro a a European Space Agency (ESA), European Space Astronomy Centre (ESAC), Villafranca, Apartado 50727, 28080 Madrid, Spain b Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, 85784 Garching, Germany c Dept. of Physics and Astronomy, Leicester University, Leicester LE1 7RH, U.K.