The XMM-Newton Slew Survey Richard Saxton1, M. Pilar Esquej14, Andy Read2, Michael Freyberg3, Bruno Altieri1, Diego Bermejo4, Veronica Lazaro4, Pedro Rodriguez1 1 ESAC 2 University of Leicester, U.K. 3 MPE, Garching, Germany 4 Universidad Complutense de Madrid, Spain

Overview - 390 slew datasets in archive (since Rev 314) - PN, MOS-1/2 exposures in Medium filter with the observing mode set to that of previous pointed observation - Average slew length is 70 degrees - Data initially available for slews longer than 30 mins duration - Closed slew, open slew, closed slew. Open slew speed = 90 degrees / hour, i.e. on-source time ~14 secs - Area covered to date ~10000 deg2 (~25% of sky)

Initial impressions New operations strategy (from end of 2004): We can process slew data with a small s/w change (available in SAS 6.5) MOS PN PN (eFF) Slew direction Extended full frame streak of 18 arcsecs Source extended into a 4 arcmin streak due to 2.6 second frame time 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 Medium filter if FF,EFF,LW and Closed for other modes 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

Galaxy Clusters XMM-Slew

Extended source analysis Source 2: 2x2 arcmin Low background and tight PSF gives good sensitivity To extended sources FF mode point sources are fitted well by a PSF, e.g. source 4 Enough counts to detect extension in brightest sources

Example extended sources Abell 3581 2 SNRs in SMC Easily detected as extended in 14 second exposure

Processing strategy Tangential projection not valid over whole slew. Divide slew into 1 deg2 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)

UY Vir DSS Image 2’×2’ Total band (0.2-12 keV) Soft band (0.2-2 keV) Hard band (2-12 keV) (RASS src)

Optical Loading – A Problem? 0.2-2.0 keV counts V Magnitude - 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 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 optical loading problems – Genuine X-ray sources

* Including high background slews Current Status (15/05/05) Initial processing of 374 slews (297 are FF, eFF or LW) – 25% have high background Images created and source searched for 125 slews giving 1651 sources in total band 1341 sources in soft (0.2-2.0 keV) band 243 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 Total of 1880 sources in ~4000 deg² ~0.5 sources per square degree 60% have RASS counterpart Completeness 2005 2010 2015 Equivalent fraction of sky covered 20 % (25)* 50% (60) 80% (100) Number of sources 4000 (5000) 10000 (12000) 16000 (20000) * Including high background slews

Survey Characteristics Source Count Distribution Exposure Time Distribution Minimum @ 4 counts Maximum @ ~ 10 seconds - Can calculate flux limits for the XMM-Slew survey

Flux limits RASS 5.0x10-13 (92% of sky) EMSS 3.0x10-12 (2% 0f sky) HEAO-1 3.6x10-11 (all-sky) Exosat 5.0x10-11 (?% of sky) RXTE 1.0x10-11 (all-sky), but with only 1° positional accuracy

Mrk 352 ESO443-IG005 MCG 04-53-021 NGC5899 Four Galaxies Non-RASS

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)

Two Merging Galaxy Pairs NGC 4748 II Zw 742

Astrometry Comparison with ROSAT survey positions shows peak at 10” … but long tail… median=31” offset Blue squares: Number of 2MASS sources vs. distance to slew source Green diamonds: Equivalent distribution for random sky positions (same number of sources) Red triangles: Difference in distributions i.e. Blue minus Green

Attitude Problem AB Dor Two types of positional error (1) Real error of ~7″ (2) Error of 0-60″ (mean 30″) but only in slew direction AB Dor Slew direction ‘Error ellipse’ around source (slew-oriented) Optimistically we can remove error (2) by re-processing the raw attitude data (RAF) A timing error of 1 sec = 90”. Timing supposed to be good to 10 ms while individual attitude points expected to be ok to within 10”.

Correlations with ROSAT Mean XMM/ROSAT=6.2 Mea Mean XMM/ROSAT = 6.2 ROSAT XMM soft

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

Several LMXB at few hundred c/s Extremely Bright Sources Several LMXB at few hundred c/s

Correlations with ROSAT All Slew sources in Galactic coordinates Green circles: RASS counterpart Red crosses: No RASS counterpart No obvious trend

Schedule - 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

Conclusions from current Slew analysis - All available (374) Slews processed (~20% of sky) (Revs 314-785, → 100% of sky by mid-2014) - 77 Slews source-searched (using best strategies): 1200 sources found in 2500 deg² (~6% of sky) ~0.5 sources per square degree - Soft X-ray band detection limit close to ROSAT All-Sky Survey - Hard X-ray band detection limit deepest ever: > 10× deeper than EXOSAT, HEAO-1 ~ 2.5× deeper than RXTE (only has 1° positional accuracy) - XMM-Slew positional accuracy ~6″ Additional ‘attitude-error’ (30″ mean), but only along slew Confident that this attitude-error can be drastically reduced - Aim to recover science from high-background slews - Encountering & solving problems en route – Still on schedule…

Conclusions from current Slew analysis - 125 Slews source-searched (using best strategies): 1880 sources found in 4000 deg² (~10% of sky) ~0.5 sources per square degree - Soft X-ray band detection limit close to ROSAT BS cat Hard X-ray band detection limit deepest ever Good sensitivity to extended sources, investigating optimum detection techniques - XMM-Slew positional accuracy ~7″ Additional ‘attitude-error’ (30″ mean), but only along slew Hopeful that this attitude error can be drastically reduced Aim to recover science from high-background slews Aim to issue first slew source catalogue before end of 2005 - Encountering & solving problems en route – Still on schedule…

Detector problems Affects one CCD so must be detector related Detector map shows events Confined to 1 CCD. Affects one CCD so must be detector related Often appear as non-single events Very soft spectrum with a peak at 100 eV Events occur within 1 frame

Spurious Sources… Sources 1 & 3 of Pilot#1 … due to crab off-axis !

Well Known Sources N132D