RAS National Astronomy Meeting 2006RAS National Astronomy Meeting 20063-7 April 2006, University of Leicester, UK3-7 April 2006, University of Leicester, UK

The XMM-Newton Slew SurveyThe XMM-Newton Slew Survey

The excellent sensitivity of the XMM-Newton satellite is strikingly apparent while manoeuvering between observation targets. These slew observations, yielding only at most 12 seconds of on-source time, constitute a hard-band 2-12 keV survey ten times deeper than all others all-sky surveys and a soft-band 0.2-2 keV survey comparable with the ROSAT all-sky survey.

Here processing challenges in the production of the First XMM-Newton Slew catalogue (XMMSL1) and highlights are outlined. Within the ~6300 square degrees uniformly covered and processed (~15% of the sky), of order of 4000 sources have been detected. Their correlation with other catalogues reveal ~50% of identifications, including a great variety of source types.

Observations and data analysisObservations and data analysis

Observations: Observations:

EPIC-pn slew observations in FF, eFF and LW with Medium filter.EPIC-pn slew observations in FF, eFF and LW with Medium filter.

Data processing: Data processing:

• Three different energy bands are processed independently:Three different energy bands are processed independently:

total band (0.2–12 keV) soft band (0.2–2 keV) hard band (2–12 keV) total band (0.2–12 keV) soft band (0.2–2 keV) hard band (2–12 keV)

• Slew observations are subdivided into 1 square degree images to maintain Slew observations are subdivided into 1 square degree images to maintain astrometry (Fig. 2).astrometry (Fig. 2).

• Sky positions are recalculated using a special Attitude file: Raw Attitude File Sky positions are recalculated using a special Attitude file: Raw Attitude File (RAF) subtracted by 0.75 seconds from every entry(RAF) subtracted by 0.75 seconds from every entry, timing error that is due to a , timing error that is due to a delay of the star tracker CCDs (Fig. 3).delay of the star tracker CCDs (Fig. 3).

• Images and exposure maps are created. They are produced containing only Images and exposure maps are created. They are produced containing only single pixel events in the 0.2-0.5 keV band, plus single and double events in the single pixel events in the 0.2-0.5 keV band, plus single and double events in the band 0.5-12 keV. band 0.5-12 keV.

• Source searching is performed using a near standard pipeline Source searching is performed using a near standard pipeline eboxdetect/emldetect tuned for ~zero background. eboxdetect/emldetect tuned for ~zero background. The low background of the The low background of the observations and the tight PSF give good sensitivity to detect extended sources observations and the tight PSF give good sensitivity to detect extended sources (Fig. 4). (Fig. 4).

• Detections in different bands are merged to produce unique source entries. Detections in different bands are merged to produce unique source entries.

• Flagging spurious sources produced by systematic effects in the instruments and Flagging spurious sources produced by systematic effects in the instruments and detection software. Several cases: detection software. Several cases: false detection, false detection, within extended source, within within extended source, within halo of bright source (Fig. 5), halo of bright source (Fig. 5), position suspect, source near edge, high position suspect, source near edge, high background.background.

• Source identification and sanity checksSource identification and sanity checks

ESACESACThe XMM-Newton Slew Survey and The XMM-Newton Slew Survey and The First Catalogue (XMMSL1)The First Catalogue (XMMSL1)

Fig 4. Upper panel: X-ray contours of the slew Fig 4. Upper panel: X-ray contours of the slew source plotted over the optical image of the Abell source plotted over the optical image of the Abell 2029 cluster. Bottom panel: The radial profile of the 2029 cluster. Bottom panel: The radial profile of the source (solid line) shows that the source is extended source (solid line) shows that the source is extended with respect to the PSF (dashed line). with respect to the PSF (dashed line).

M.P. EsquejM.P. Esquejaa, R.D. Saxton, R.D. Saxtonbb, A.M. Read, A.M. Readcc, M. J. Freyberg, M. J. Freybergaa, B. Altieri, B. Altieribb aaMax-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, 85784 Garching, GermanyMax-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, 85784 Garching, Germany

bbEuropean Space Agency (ESA), European Space Astronomy Centre (ESAC), Villafranca, Apartado 50727, 28080 Madrid, Spain European Space Agency (ESA), European Space Astronomy Centre (ESAC), Villafranca, Apartado 50727, 28080 Madrid, Spain ccDept. of Physics and Astronomy, Leicester University, Leicester LE1 7RH, U.K. Dept. of Physics and Astronomy, Leicester University, Leicester LE1 7RH, U.K.

Current statusCurrent status

219 slews processed219 slews processedSource detections (det_ml>8): 4179 in total band, 2752 in soft Source detections (det_ml>8): 4179 in total band, 2752 in soft band, 845 in hard band.band, 845 in hard band.Number of sources (merging detections in different energy Number of sources (merging detections in different energy bands): bands): 5200 sources 5200 sourcesSpurious sources: 532Spurious sources: 532Some overlap: 105 sources seen in more than one slewSome overlap: 105 sources seen in more than one slew

Average slew length: ~70 degreesAverage slew length: ~70 degreesAverage on-source time: ~7 secondsAverage on-source time: ~7 secondsPositional accuracy: 8 arcsecPositional accuracy: 8 arcsecSource density: ~0.65 sources per square degreeSource density: ~0.65 sources per square degreeSky coverage: ~6300 square degrees (~15% of the sky)Sky coverage: ~6300 square degrees (~15% of the sky)

Fig 3. Comparison of data processing with different attitude files used for the astrometry reconstruction. Right images: detected slew source in the total band. Left images: position of the slew source overplotted on a DSS image. Top panel: source detected with the AHF as attitude file, the shift between the optical and the slew position is obvious. Bottom panel: corrected slew source position using the modified RAF for the attitude reconstruction. We can clearly see the difference between both processings and the improvement with the new attitude reconstruction.

Fig 2. Slew observation performed with the EPIC- pn camera. Red boxes show subimages for processing.

Fig 5. Extended source detected in revolution 0880. The real slew source is red circled. Spurious detections within the halo of this bright source are shown in light blue.

The catalogueThe catalogue

Two catalogues have been produced:Two catalogues have been produced:• Total catalogue: all detected sources (det_ml>8).Total catalogue: all detected sources (det_ml>8).• Clean catalogue: including det_ml>14 sources and Clean catalogue: including det_ml>14 sources and det_ml>10 & (high energy) bg_rate<3 sources.det_ml>10 & (high energy) bg_rate<3 sources.

Each one of the catalogue entries has columns related to:Each one of the catalogue entries has columns related to:• Details of the observations.Details of the observations.• Source parameters in the different detection bands from Source parameters in the different detection bands from the source detection: counts, flux, extension, etc.the source detection: counts, flux, extension, etc.• Flags to qualify the sources. Flags to qualify the sources. • Identifications: one derived from cross-correlations with Identifications: one derived from cross-correlations with different astronomical databases and catalogues and a different astronomical databases and catalogues and a RASS counterpart.RASS counterpart.

Publication: April 2006Publication: April 2006Available via the XMM-Newton Science Archive (XSA)Available via the XMM-Newton Science Archive (XSA)

Fig 6. 3D distribution of the XMMSL1 sources in galactic coordinatesFig 6. 3D distribution of the XMMSL1 sources in galactic coordinates

Fig 1. Flux limits of X-ray surveys in the soft band (left panel) and the hard band (right panel). Fluxes for the XMM-slew survey have been calculated for a source with Flux limits of X-ray surveys in the soft band (left panel) and the hard band (right panel). 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 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 NH=3.0·10power-law model with NH=3.0·102020 cm cm22 and slope 1.7 and slope 1.7