The X-ray Universe September 2005, El Escorial, Madrid, Spain Extended Sources in the XMM-Newton slew survey V. Lazaro a, R. Saxton a, A.M.Read c,M.P. Esquej a, M.J. Freyberg b, B. Altieri a,D. Bermejo a V. Lazaro a, R. Saxton a, A.M.Read c,, M.P. Esquej a, M.J. Freyberg b, B. Altieri a,D. Bermejo a a European Space Agency (ESA), European Space Astronomy Centre (ESAC), Villafranca, Apartado 50727, Madrid, Spain b Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, Garching, Germany c Dept. of Physics and Astronomy, Leicester University, Leicester LE1 7RH, U.K. Clusters of Galaxies ESACProcessing Introduction The XMM-Newton slew survey project will catalogue of the order of 4000 sources from 15% of the sky, with a limiting flux of about ergs s -1 cm -2 in the keV energy band. About 10% of these sources are reported to be extended by the source detection software. Categories represented are:  Clusters of galaxies  Nearby galaxies  Supernova Remnants Equatorial coordinates of extended sources on the sky The low background and great sensitivity of the EPIC- pn camera on XMM-Newton gives useful limits for the detection of extended sources. This poster attempts to illustrate the potential of the slew survey as a tool for analysing flux-limited samples of clusters of galaxies and other sources of spatially extended X-ray emission. EMASK Detection Mask EBOXDETECT (local mode) Eboxdetect Local Mode Source List ESPLINEMAP Spline Background Map EBOXDETECT (map mode) Eboxdetect Map Mode Source List EMLDETECT Emldetect Source List Exposure Image dmlextmin | extentmodel | ml_id_src | scts | ext | det_ml | ext_ml | bg_map | exp_map | ra | dec | gaussian | 1 | | | | | | | | | beta | 1 | | | | | | | | | gaussian | 1 | | | | | | | | | beta | 1 | | | | | | | | | gaussian | 1 | | | | | | | | | beta | 1 | | | | | | | | | gaussian | 1 | | | | | | | | | beta | 1 | | | | | | | | | gaussian | 1 | | | | | | | | | beta | 1 | | | | | | | | | gaussian | 1 | | | | | | | | | beta | 1 | | | | | | | | | gaussian | 1 | | 0 | | 0 | | | | | gaussian | 2 | | 0 | | 0 | | | | | beta | 1 | | 0 | | 0 | | | | | beta | 2 | | 0 | | 0 | | | | This is the processing schema for source detection. To identify the best parameters to use for detecting extended sources within the slew data, a set of training images, consisting of known extended sources, were identified. The software was run on these images varying the dmlextmin parameter and the extent model. It was found that the actual value of dmlextmin wasn’t important as long as it didn’t exceed 10. Using a beta model generally gave a greater extent size and more counts. A smoothed slew image of the SNR Puppis-A compared with a 7ks ROSAT HRI observation. The blue circles represent the individual detections made by the source search software, illustrating how difficult it is to automatically parameterise very extended sources. Slew X-ray contours of the VELA SNR overlaid on an optical image X-ray contours of two close SNRs in the Small Magellenic Cloud overlaid on a DSS image Supernova Remnants The slew survey covers a large sky area to a depth which is comparable with some of the better previous X-ray cluster surveys. In the regions of overlapping slews, such as the ecliptic poles, co-adding data will lead to a still deeper survey albeit over a smaller area. Abell 3581 An energy encoded smoothed image of Abell Red represents soft (0.2-2 keV) photons and blue the hard (2-12 keV) photons. XMM-Slew Comparison of cluster survey areas and depths A plot of detected counts against detected extension. Points coincident with known clusters are circled in green. The extension is shown in units of 4.1” pixels and the software search is limited to 20 pixels. Some clusters, apparently detected with zero extension, may in fact be coincidences with real point sources. The branch showing increasing extension for very bright sources is due to pile-up effects distorting the radial profile. Cross-correlations with the Abell and Zwicky catalogues show 55 coincidences with known clusters in the slew survey. Of these, 37 are detected as extended objects. The very brightest examples contain greater than 100 counts, sufficient to allow crude spectral imaging. Redshift distribution for detected Abell and Zwicky clusters plotted against the keV flux. Determine which is the image area where the detection is going to take place Find probable and not so probable sources Remove these sources from the image and interpolate across the remaining data to get a splined better model of the background Improvement of the list of sources using this model of the background Best detection and source parametrization with emldetect The exposure map, detection mask and spline background of Abell 3581 Results obtained for Abell 3581 Summary of source detection