1. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 1 The XMM-Newton Slew Survey: processing challenges Richard Saxton 1, Bruno Altieri 1, Diego Bermejo 4, M. Pilar Esquej 1,4, Michael Freyberg 3, Veronica Lazaro 4, Andy Read 2 1 ESAC, ESA, Spain 2 University of Leicester, U.K. 3 MPE, Garching, Germany 4 Universidad Complutense de Madrid, Spain

2. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 2 Talk outline Survey characteristics Survey characteristics Processing Processing Attitude reconstruction: Astrometry (1) Attitude reconstruction: Astrometry (1) Spurious sources Spurious sources Optical loading (2)Optical loading (2) Detector flashes (3)Detector flashes (3) Sensitivity Sensitivity Extended sources Extended sources

3. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 3 XMM-Newton 3 mirror modules with 58 shells each 3 mirror modules with 58 shells each EPIC: EPIC: 2 MOS CCD cameras2 MOS CCD cameras 1 pn CCD camera1 pn CCD camera 2 Reflecting Grating Spectrometers 2 Reflecting Grating Spectrometers 1 Optical Monitor 1 Optical Monitor

4. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 4 Survey Characteristics Average slew length : 86 degrees

5. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 5 Overview - 465 slew datasets in archive (since Rev 314, end-2001) - PN, MOS-1/2 exposures in Medium filter with the observing mode set to that of previous pointed observation - Data initially available for slews longer than 30 minutes duration - Open-slew speed = 90 degrees / hour, i.e. on-source time ~14 secs - Area covered to date ~8000 deg 2 (~20% of sky) ecliptic coordinates great circles passing through ecliptic poles due to sun constraint.

6. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 6 Processing strategy Tangential projection not valid over whole slew. Divide slew into 1 deg 2 images and recalculate sky positions. Source search using near-standard pipeline eboxdetect/emldetect combination tuned for ~zero background. Use sources with DET_ML > 10 equivalent to 3.9 sigma Search independently in three bands and produce three catalogues :  soft (0.2-2 keV)  hard (2-12 keV)  total (0.2-12 keV)  Dedicated pipeline MPE/ESAC/LUX with database at ESAC

7. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 7 Initial impressions Source extended into a 4 arcmin streak due to 2.6 second frame time Full frame (73ms) mode streak = 6 arcsecs – not noticeable Extra pn sensitivity + additional MOS background means little to be gained from analysing MOS slews Epic-pn attitude reconstruction good MOS PNPN (eFF) Extended full frame streak of 18 arcsecs Slew direction We can process slew data with a small s/w change (available in SAS 6.5) New operations strategy (from end of 2004): MOS slews will be used for calibration MOS slews will be used for calibration All PN slews longer than 15 mins will be down-linked and processed and used for science All PN slews longer than 15 mins will be down-linked and processed and used for science Medium filter if FF,EFF,LW and Closed for other modes Medium filter if FF,EFF,LW and Closed for other modes

8. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 8 EPIC-pn source characteristics Source Count DistributionExposure Time Distribution Minimum @ 4 countsMaximum @ ~ 10 seconds Mean 6.3 - Can calculate flux limits for the XMM slew survey

9. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 9 Current Status (15/07/2005) 200520102015 Equivalent fraction of sky covered 20 % (25)*50%(60)80%(100) Number of sources 4000(5000)10000(12000)16000(20000) Completeness * Including high background slews Initial processing of 374 slews (297 are FF, eFF or LW) – 25% have high background Images created and source searched for 138 slews giving 1596 sources in total band 1231 sources in soft (0.2-2.0 keV) band 221 sources in hard (2.0-12.0 keV) band At faint end, 169 soft-band and 61 hard-band sources, not detected in the total band Source density: ~0.5 sources per square degree 60% have RASS counterpart

10. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 10 Astrometry: initial comparison Comparison with ROSAT survey positions shows a wide distribution, with a tail up to 1 arcmin median=31” offset

11. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 11 Attitude Problem: correction Two types of positional error (1) Real error of ~10″ (2) Error of 0-60″ (mean 30″) but only in slew direction Slew direction AB Dor  ‘Error ellipse’ around source (slew-oriented) Good relative astrometry: ~10 arcsec, but poor absolute astrometry: ~30 arcsec Systematic shift was evidenced, traced to : quantisation of time to 1 second in AHF timing error in the RAF, due to a delay of 0.75s of the star tracker CCDs leading to a systematic offset

12. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 12 Achieved astrometric accuracy RASS : 16”Simbad : 8” Close to the theroretical limit !

13. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 13 Optical Loading – A Problem? Contrary to pointed observations, no offset maps is computed/applicable.  Possibility of optical loading contamination

14. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 14 UY Vir DSS Image 2’×2’Total band (0.2-12 keV) Hard band (2-12 keV)Soft band (0.2-2 keV) (RASS src)

15. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 15 Optical Loading – A Problem? CD 36-1289 : X-ray emission from this V=10.5 star, but none from neighbours at V=6.5 and V=7.6 Several examples like this - No correlation between source counts and Vmag for bright stars - Consistent with optical loading predictions: 5 counts expected above 200eV only for stars brighter than V=3.75 No optical loading problems : genuine X-ray sources R Magnitude (USNO) 0.2-2.0 keV counts

16. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 16 Detector problems Affects one CCD so are detector related Often appear as non-single events Very soft spectrum with a peak at 100 eV Events occur mostly within 1 frame Detector map shows events Confined to 1 CCD.

17. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 17 Detector flashes Short duration CCD flashes with very soft spectrum Effect minimized by using single events only below 500 eV

18. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 18 Starting the NASS (Newton All-Sky Survey Aitoff projectiongalactic coordinates

19. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 19 RASS: RASS: 5.0x10 -13 (92% of sky) EMSS: EMSS: 3.0x10 -12 (2% 0f sky) HEAO-1: HEAO-1: 3.6x10 -11 (all-sky) Exosat: Exosat: 5.0x10 -11 (?% of sky) RXTE: RXTE: 1.0x10 -11 (all-sky), but with only 1 ° positional accuracy X-ray All-Sky Surveys : Flux limits NASS: NASS: 6(4.5) 10 -13 ergs s -1 cm -2 in the soft band (0.5-2.0 keV) 4(3) 10 -12 ergs s -1 cm -2 in the hard band (2-10 keV)

20. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 20 Extended source analysis Source 2: 2x2 arcmin FF mode point sources are fitted well by a PSF, e.g. source 4 Low background and tight PSF gives good sensitivity To extended sources Enough counts to detect extension in brightest sources

21. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 21 Example extended sources Easily detected as extended in 14 second exposure Abell 35812 SNRs in SMC

22. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 22 XMM-Slew Galaxy Clusters

23. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 23 Four Galaxies ESO443-IG005Mrk 352 MCG 04-53-021NGC5899 Non-RASS

24. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 24 Sources detected in separate slews - Source detected in 3 separate slews: Rev 0570, Rev 0573, Rev 0574 - Known ROSAT source (+faint galaxy) - Evidence for variability (factor ~2)

25. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 25 Two Merging Galaxy Pairs NGC 4748 II Zw 742

26. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 26 Correlations with ROSAT XMM soft ROSAT Mean XMM/ROSAT ~ 10

27. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 27 Correlations with ROSAT All Slew sources: Hardness ratio vs Galactic latitude Blue circles: No RASS counterpart Red crosses: RASS counterpart Hard sources not seen by ROSAT RASS sources on average softer than non-RASS sources

28. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 28 Extremely Bright Sources Several LMXB at few hundred c/s

29. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 29 Conclusions from current Slew analysis  138 slews source-searched (using best strategies): 1596 sources found in 3400 deg² (~10% of sky) ~0.5 sources per square degree  Soft X-ray band detection limit close to ROSAT BS catalogue  Hard X-ray band detection limit deepest ever:  > 10× deeper than EXOSAT, HEAO-1  ~ 2.5× deeper than RXTE (only has 1° positional accuracy)  Good sensitivity to extended sources, investigating optimum detection techniques  XMM-Slew positional accuracy ~8″  Aim to recover science from high-background slews  Encountering & solving problems en route …  Aim to issue first slew source catalogue before end of 2005

30. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 30 Well Known Sources N132D

31. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 31

32. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 32

33. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 33 Correlations with ROSAT All Slew sources in Galactic coordinates Green circles: RASS counterpart Red crosses: No RASS counterpart No obvious trend

34. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 34 Spurious Sources… … due to crab off-axis !Sources 1 & 3 of Pilot#1

35. SPIE, San Diego, CA - 1 August 2005 Bruno Altieri, XMM-Newton European Space Astronomy Centre Page 35Schedule - Initial processing of slew data (finished) - Solve attitude/astrometry problems – asap - Creation of images, source searching, rejection of spurious sources (Feb to July) - Investigate optimum extended source extraction methods (April to Oct) - Creation of final catalogue for ingestion into XSA (Aug to Oct) - Ingestion into XSA (end of November) - Provide flux / upper limits server (early 2006) - Search co-added slews (?) - Investigate going down to DET_ML=8 (?) - Regular updates with newly processed slews