The XMM-Newton Slew Survey Richard Saxton, Andy Read, M. Pilar Esquej, Michael Freyberg, Bruno Altieri, Diego Bermejo, Veronica Lazaro

Overview 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 available for slews > 30 mins - Closed slew, open slew, closed slew. Open slew speed = 90 degrees / hour, i.e. on-source time ~14 secs - Area covered to date ~10000 deg 2 (~25% of sky)

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:  MOS slews will be used for calibration  All PN slews larger than 15 mins will be down-linked and processed and used for science  Medium filter if FF,EFF,LW and Closed for other modes

XMM-Slew Galaxy Clusters

Extended source analysis Low background and tight PSF gives good sensitivity to extended sources Abell 3581 SNRs in SMC ZW CL

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

Abell 3581 Easily detected as extended in 14 second exposure (EFF mode) Slew direction

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 ( keV)

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

Optical Loading Assessment ~10% sources coincident with bright stars - Optical loading or genuine X-ray sources? DSS images on slew positionsDSS on slew positions + 1hour RA

Optical Loading – A Problem? keV counts V Magnitude CD : 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

Current Status - Initial processing and event file creation for all available Slews Slews: 297 of which are FF (206), eFF (61) or LW (30) - 20% have “high” background - 20% have “high” background Slews: Images & exposure maps created & source-searched sources in total ( keV) band sources in soft ( keV) band sources in hard ( keV) band - At faint end, soft-band sources, not - detected in the total band - 57 hard-band sources, not - 57 hard-band sources, not detected in the total band detected in the total band - Total of 1600 sources in ~3500 deg² ~0.5 sources per square degree - 60% have RASS counterpart (01/05/05) Fraction of sky covered 20 % (25)*50%(60)80%(100) Number of sources 4000(5000)10000(12000)16000(20000) Completeness * Including high background slews

Soft source not detected in full energy band Hard source not detected in full energy band Extra background in full-energy band (sometimes just 1 photon!) can flip statistics below the threshold (DET_ML=10) Faint sources detected in soft/hard- band but not in full-band

Survey Characteristics Source Count DistributionExposure Time Distribution ~ 4 ~ 10 seconds ( effective on-axis exposure) (45% of 4-count sources have RASS counterpart)

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

Astrometry 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 Pointing accuracy of Slew survey ~6″ … but long tail…? 2MASS RASS

Attitude Problem Two types of positional error (1) Real error of ~6″ (2) Error of 0-60″ (mean 30″) but only in slew direction Slew direction AB Dor ‘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 s = 90”. Timing supposed to be good to 10 ms, individual attitude points expected to be ok to within 10”.

Correlations with ROSAT Mean XMM/ROSAT=6.2 XMM-soft/ROSAT Source type 8230 LMXB/T 771 ? 358 ? 272 ? 215 ? 213 EB*Algol 172 ? 152 EB*BetLyr 128 ? 122 Radio Galaxy ? 119 Flare star 0.05 Star XMM soft ROSAT Mea Mean XMM/ROSAT = 6.2

Correlations with ROSAT All Slew sources: Hardness ratio v Galactic latitude Green circles: No RASS counterpart Red crosses: RASS counterpart Many hard sources not seen by ROSAT RASS sources on average softer than non-RASS sources

Four Galaxies ESO443-IG005Mrk 352 MCG NGC5899 Non-RASS

Extremely Bright Sources Several LMXB at few hundred c/s

Sources detected in separate slews - Source detected in 3 separate slews: Rev 0570, Rev 0573, Rev Known ROSAT source (+faint galaxy) - Evidence for variability (factor ~2)

Two Merging Galaxy Pairs NGC 4748 II Zw 742

Initial Conclusions ∞ MOS slew data effectively useless for science ∞ Optical loading not an issue ∞ High background affects % of slews ∞ Expect to find ~ 4,000 sources from current data ∞ Sensitive to extension in brighter sources ∞ ~40% of sources not present in RASS ∞ Soft band detection limit similar to RASS all-sky limit ∞ Deepest 2-10 keV “all sky” survey to date at 4x New operations strategy:  MOS slews will be used for calibration (see MK talk)  All PN slews larger than 15 mins will be down-linked and processed and used for science  Medium filter if FF,EFF,LW and Closed for other modes

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 Slews source-searched (using best strategies): 1600 sources found in 3500 deg² (~9% 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 e detection techniques - XMM-Slew positional accuracy ~6″ 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 Encountering & solving problems en route – Still on schedule…

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

The XMM Slew Survey : current processing scheme - Processing of slew data (creation of event files) - Creation of images, exposure maps (full-, soft- and hard-band) - Source search full-, soft- and hard-band images using exposure maps - Make catalogue of detections - Make DSS images for each detection - Check for and flag spurious sources - Check for and flag optical loading due to bright stars - Find hardness ratios from individual band images - Make clean catalogue of sources - Cross-correlate with Rosat - Cross-correlate with other catalogues (In preparation…) (In preparation…) - Analyse extensions - Co-add slews and re-search - Optical follow-up, piggy-back on XID program

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

Well Known Sources N132D