XMM-Newton 1 D Lumb -- SCI-ST. EPIC TTD Nov01 EPIC Background Template Files Why we need them - previous attempts insufficient Adding together high galactic latitude files - choices & screening Comments on the internal background in MOS Using the files astrophysically - seem consistent with ROSAT/ASCA and other historic data Future developments - SAS task needed ?

XMM-Newton 2 D Lumb -- SCI-ST. EPIC TTD Nov01 Context Extended objects are an important field of XMM science Background surface brightness relatively high and variable need a good estimate of background which does not rely on the in-field subtraction “Band-aid” background files provided for A&A special issue analysis (using Lockman Hole and selected calibration fields) S:N too low, heterogeneous field selection (N H, filters), also the exposure corrections uncertain for use

XMM-Newton 3 D Lumb -- SCI-ST. EPIC TTD Nov01 Field Choice & Locations Chose all THIN filter (most extended objects use THIN & easier to make a change for other filters if homogeneous data set has been employed) High galactic latitude away from any obvious features in the halo or near bright point sources Low proton background, low N H, long observations from calibration, PV or SOC data sets where possible to minimise data rights issues If a typical GO observation is ~30ksecs, then aim for 10 times this for a reasonable signal:noise

XMM-Newton 4 D Lumb -- SCI-ST. EPIC TTD Nov01 Field Locations (contd.) RA Dec DateTimeN_ H L IIBII 2000(ks)(10 20 ) 02:18:00 -05:00: :19:36 -05:00: :25:20 -05:10: :28:00 -05:10: :52:44 +57:28: :36:57 +62:13: :34:37 +37:54: :15:31 -17:44:

XMM-Newton 5 D Lumb -- SCI-ST. EPIC TTD Nov01 Source Extraction Need to remove bright sources, but as lots of the XMM background normally gets resolved, we cannot remove ALL or it is not representative for the observer’s field! By co-adding several fields there is some dilution effect, and as long as it is OK on ~arcminute levels and << ergs source level, it will probably cover most eventualities Avoid arbitrary manual removal, so used EBOXDETECT (0.5- 2keV, local mode only), noting ~ 10 brightest locations and excise from 50 arcsec diameter ( > ~80% flux each) Based on LogN-LogS this cut must be ~1.5 x ergs, which after dilution >5 means only very faint effective residual (confirm by manual inspection) point source content

XMM-Newton 6 D Lumb -- SCI-ST. EPIC TTD Nov01 File Creation Screening of proton flares (PI>10000&&PATTERN==0) at 4  in 100 sec time bins (if screening is too tight may not match observers’ cuts) Concatenate the event list in time, apply exposure extensions from original files (also concatenated), badpix, offset, GTI extensions left in Hide identity of original fields, modify keywords to be homogenous and consistent (START, STOP, FRACEXP, LIVETIME etc.) Basic duration now >400ksec, but observer might consider further screening to match own data set which now should be possible as extensions are coherent (I think that 350ksec is closer to usable quiet duration)

XMM-Newton 7 D Lumb -- SCI-ST. EPIC TTD Nov01 What does it look like? DETX,DETY coords, MOS1 & PN (E>250eV)

XMM-Newton 8 D Lumb -- SCI-ST. EPIC TTD Nov01 MOS Al & Si Al weaker around edge of centre CCD, Si is reverse

XMM-Newton 9 D Lumb -- SCI-ST. EPIC TTD Nov01 PN Cu & Soft band Metal emission lines with central hole Soft band dominated by streaks

XMM-Newton 10 D Lumb -- SCI-ST. EPIC TTD Nov01 MOS Internal Background Can use the substantial area outside filter to determine the true internal background component Flat spectrum above 1keV, count rate consistent with CR rate and 99.5% rejection Steeply rising low energy background – worse in MOS2 than MOS1 – correlated with the bad and flickering pixels? Al and Si emission lines variable so cannot use as simple subtraction for an IN-FIELD. Choose a model of several Gaussians and broken power law Use this as a “background” component for in-field but change normalisations according to surface area, but allow emission line intensities to be free parameter

XMM-Newton 11 D Lumb -- SCI-ST. EPIC TTD Nov01 MOS Internal Background Al Si & Au Cr, Mn Fe Au

XMM-Newton 12 D Lumb -- SCI-ST. EPIC TTD Nov01 Astrophysical Analysis With a high signal:noise and reasonable internal background characterisation we can attempt astrophysical analysis. Produce focal plane vignetting averaged response file and fit MOS1 & MOS2 simultaneously Extragalactic power law seems consistent (harder than 1.4 unless the bright sources put back in) – but careful analysis of the out of field scattered component and the cosmic variance to brighter sources may allow a resolution to the long-standing background normalisation problem Soft component temperature models are consistent with Kuntz&Snowden analysis, but the LHB components poorly constrained (calibration problems)

XMM-Newton 13 D Lumb -- SCI-ST. EPIC TTD Nov01 Future Development Could produce further additions for deeper fields? Need to fix for filters and galactic location, possibly even CR variations: A task can be envisaged 1) Takes the model for internal component scaled by CR rate proxy 2) Produce soft component based on ROSAT multi-band analysis for the appropriate L II & B II (Steve Snowden working on tool) 3) Filter choice then added through the appropriate response matrix 4) Proton screening still a problem?