M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 1 Status of the XMM-Newton Slew Survey P. Esquej, R. Saxton, B. Altieri, A. Read, M. Freyberg, D. Bermejo, V. Lazaro

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 2 Outline Overview & initial impression about the XMM- Newton slew observations Data processing & source searching strategy: current status Attitude reconstruction and positional accuracy Spurious sources Extended sources Sensitivity Small sample of detected sources Conclusions

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 3 Overview - XMM-Newton performs slewing manoeuvers between targets with the EPIC cameras open and the other instruments closed - PN, MOS-1/2 exposures in Medium filter with the observing mode set to that of previous pointed observation - Open-slew speed = 90 degrees / hour, i.e. on-source time ~14 secs - Area covered to date ~6300 deg 2 (~15% of sky) ecliptic coordinates slew datasets in archive (since Rev 314) - Data initially available for slews longer than 30 minutes - Average usable slew length is ~60 degrees

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 4 Initial impressions MOS PN New operations strategy (from end of 2004): -MOS slews will be used for calibration -All PN slews longer than 15 mins will be down-linked and processed and used for science: XMM Slew Survey -Medium filter if FF, eFF, LW and Closed for other modes Very low background of average ~0.1 c/arcmin 2 due to the low exposure time. But some slews taken in time of enhanced solar activity exhibit high background giving rise to spurious sources Source appearance depends on the frame time of the observing mode - MOS cameras: spread source into a 4 arcmin streak - pn camera: source extension less than 18 arcsec

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 5 Processing strategy -Slew data processing using a small s/w change (available in SAS 6.5) -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  ) -Search independently in three bands and produce three catalogues : soft (0.2-2 keV) hard (2-12 keV) total ( keV)

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 6 Current Status Equivalent fraction of sky covered 15%(20)*45%(55)80%(~100) Number of sources 4000(5500)12000(15000)20000(25000) Completeness * Including high background slews - Initial processing of 424 slews (FF, eFF or LW) – 25% have high background - Images & exposure maps created and source searched for 220 slews giving 4178 sources in total ( keV) band 2750 sources in soft ( keV) band 844 sources in hard ( keV) band Source density: ~0.65 sources per square degree ~56% have RASS counterpart within 60 arcsec

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 7 Attitude Reconstruction - Crucial in determination of source coordinates - Provided by the AOCS: a star-tracker operates in adition with the Sun-sensor provide the information for reconstructing the astrometry (1 arcsec for pointed observations) - Two types of attitude data can be used during event file processing: Raw Attitude File (RAF) and Attitude History File (AHF) -Different in slew observations than that used for pointed observations

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 8 Astrometry: initial comparison Comparison with ROSAT survey positions shows a wide distribution, with a tail up to 1 arcmin Two types of positional error (1) Real error of ~15″ (2) Error of 0-60″ (mean 30″)

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 9 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: ~15 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 Optimal attitude file: RAF subtracted by 0.75 s from every entry

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 10 Achieved astrometric accuracy RASS : 15” (1  )SIMBAD : 8” (1  )

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 11 Spurious sources - Detector flashes: avoided by only using single pattern below 0.5 keV - Within extended or within halo of bright source: can be spotted looking for images with high number of sources - High background images: spurious detections due to localised background flares - Position suspect: several cases - False detection: background related?

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 12 Extended vs point-like sources 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 Point-like source Extended source

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 13 Example of extended sources Easily detected as extended in 14 second exposure Abell SNRs in SMC

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 14 XMM-Newton Slew 1 (XMMSL1) Aitoff projection

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 15 RASS: RASS: 5.0x (92% of sky) EMSS: EMSS: 3.0x (2% 0f sky) HEAO-1: HEAO-1: 3.6x (all-sky) Exosat: Exosat: 5.0x (98% of sky) RXTE: RXTE: 1.0x (all-sky), but with only 1 ° positional accuracy X-ray All-Sky Surveys : Flux limits XMMSL1: XMMSL1: 6(4.5) ergs s -1 cm -2 in the soft band ( keV) 4(3) ergs s -1 cm -2 in the hard band (2-10 keV)

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 16 Sources detected in separate slews - Source detected in 3 separate slews: Rev 0570, Rev 0573, Rev Known ROSAT source - Evidence for variability (factor ~2)

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 17 Correlations Slew-soft with ROSAT XMM soft ROSAT Mean XMM/ROSAT ~ 10 We can study source variability

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 18 Galaxies ESO443-IG005Mrk 352 MCG NGC5899 Non-RASS

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 19 Merging Galaxy Pairs NGC 4748 II Zw 742

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 20 Several LMXB at few hundred c/sN132D More sources...

M. Pilar Esquej, XMM-Newton European Space Astronomy Centre Page 21 Conclusions 220 slews source-searched (using best strategies): 4013 sources (after removing spurious sources) Sky coverage: ~6300 deg 2 (~15% of sky) ~0.65 sources per square degree XMM-Slew positional accuracy ~8″ 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) Topics under current investigation: optical correlation, refinement of spurious detection, source extension strategy, recovering science from high-background slews Aim to issue first slew source catalogue (XMMSL1) before end of 2005 Provide an upper limit server in 2006