Bruno Altieri EPIC Calibration meeting, Feb. 1-3, 2005 European Space Astronomy Centre Page 1...

Bruno Altieri Bruno Altieri EPIC Calibration meeting, Feb. 1-3, 2005 EPIC Calibration meeting, Feb. 1-3, 2005

European Space Astronomy Centre

XMM-NewtonXMM-Newton

ESACESAC

Status of XMM-NewtonStatus of XMM-Newtoncross-calibration with SAS-6.1cross-calibration with SAS-6.1

B.AltieriB.Altieriwith inputs/support from whole cross-calibration team with inputs/support from whole cross-calibration team

(XMM SOC, Leicester, MPE(XMM SOC, Leicester, MPE))




ESACESACTalk outlineTalk outline

• Response stability at low energies : Response stability at low energies : • SNR (extended)SNR (extended)• AGN view (trend analysis)AGN view (trend analysis)

• Low-energy problem: effect of the new pn Low-energy problem: effect of the new pn redistribution in SAS-6.1redistribution in SAS-6.1

• Spectral fitting examples on various type of Spectral fitting examples on various type of sourcessources

• Chandra/Newton cross-calibrationChandra/Newton cross-calibration• Other cross-calibration problems:Other cross-calibration problems:

MOS low-energy overestimated redistributionMOS low-energy overestimated redistribution EPIC high-energy discrepancyEPIC high-energy discrepancy Fudging RGS low-energy (<0.5 keV) effective area Fudging RGS low-energy (<0.5 keV) effective area

proposal proposal • ConclusionsConclusions




ESACESACEPIC-pn flux stability: N132DEPIC-pn flux stability: N132D

EPIC-pn is stable

M.P. Esquej




ESACESACEPIC-pn Flux stability: RXJ1856EPIC-pn Flux stability: RXJ1856

F. Haberl

• Confirmed by the Isolated Neutron star:

EPIC-pn is extremely stable




ESACESACMOS flux stability: N132DMOS flux stability: N132D

Rev771: • flux decrease in 0.5-1 keV• Redistributed below 0.4 keV

Rev 828 :• Less clear, especially MOS2, while at the same distance relative to low-E on-axis patch.

Some changes at low energies (0.5-1keV) at ~5% level.

• spatial dependent• time dependent

Rev 771Rev 771 Rev 828Rev 828




ESACESACMOS flux stability: N132D (2)MOS flux stability: N132D (2)

Why MOS’s see more flux Why MOS’s see more flux deficit in 0.5-1 keV band in deficit in 0.5-1 keV band in rev.771 than rev.828 ? rev.771 than rev.828 ?

While it is relatively at the While it is relatively at the same distance from the on-same distance from the on-axis patch.axis patch.




ESACESACEPIC flux stability: N132DEPIC flux stability: N132D

N132D 0.4-0.8 keV band:

• EPIC-pn: pn flux is stable pn-LW lower fluxes than pn-SW due to pile-up

• MOSs : MOS1 lower than MOS2 by 5% Both MOSs have decreased by 6% since launch

MOS2 lower than pn by 10% at launch up to 15% by rev.~800 MOS1 lower than pn by 15% at launch up to 20% by rev.~800 But MOS/pn normalisation TBD because of possible small pile-up for MOSs.

M.P. Esquej




ESACESACMOS flux stability: 1ES0102MOS flux stability: 1ES0102

1ES0102 0.4-0.8 keV band:

• MOS cameras seems stable in flux since launch but ..

for off-axis positions• also consistent with a 5% decrease.

• 10% lower flux observed on-axis where a spatially dependent degraded redistribution has developed (‘patch’)

A.M.R. Read




ESACESACMOS on-axis low-E patch (1)MOS on-axis low-E patch (1)

A.M.R. Read

When the SNR is centered close to on-axis position one observes :

• a deficit in 0.35-0.7 keV• an excess below 0.3 keV




ESACESACMOS on-axis low-E patch (2)MOS on-axis low-E patch (2)

MOS low-E patch elongated along the MOS low-E patch elongated along the line joining the 2 bore-sights.line joining the 2 bore-sights.

A.M.R. Read




ESACESACEPIC Low-energy flux stability :EPIC Low-energy flux stability :The SNR storyThe SNR story

EPIC-pn stable below 2 keV and particularly in the 0.4-0.8 keV band

MOSs were possibly ~10% below EPIC-pn at launch in 0.4-0.8 keV with MOS1 5% lower than MOS2

MOSs seem to have lost 5%+ since launch, in the 0.4-1 keV band

possibly redistributed to lower energies (< 0.4 keV) where a low-energy patch is observed on-axis.




ESACESAC

Sample of AGNs mostly in SW/Medium analysed in 15-40 arcsec annulus used, hence excluding the “MOS patch.”

Low-energy problem :

• Either MOSs & RGSs loose flux relative to pn at the same rate : 8% in 800 revs (I) because of :

• MOS on-axis redistribution ?• RGS ??• contamination of MOSs and RGSs, cooler CCDs than pn.

• or pn is gaining flux at the same rate (II) : • filters degradation discarded from SNRs• redistribution ?

Flux stability: The AGN viewFlux stability: The AGN view

S. Sembay

(I)

(II)

cooling




ESACESACRGS flux stability: 1ES0102RGS flux stability: 1ES0102

red: 0.33-0.7 keV, green: 0.7-0.972 keV, blue: 0.972-1.74 keV

A.Pollock

M. Smith

• At other energies > 0.7 keV, it seems stable contamination ?contamination ?

• RGS flux in 0.4-0.8 keV band consistent with a 5-8% decrease but :

• very little flux below 0.55 keV• background subtraction not easy for extended source, ~20% of the flux• not confirmed by Zeta Puppis Nitrogen line flux monitoring (preliminary result, full analysis underway, by A. Pollock)




ESACESAC

Somewhat contradictory results :Somewhat contradictory results :– EPIC-pn seems stableEPIC-pn seems stable– MOS response is changingMOS response is changing

– loosing flux in 0.4-1 keV- redistributed below 0.4 keV– In the on-axis area (‘patch’) only ?

– RGS constant ? Study of RGS stability crucialRGS constant ? Study of RGS stability crucial

MOS: Contamination or redistibution only ?MOS: Contamination or redistibution only ? Exact amount of variations ?Exact amount of variations ? Why RGS and MOS relative calibration is Why RGS and MOS relative calibration is

unchanged ?unchanged ?– RGS and MOS CCDs are coolerRGS and MOS CCDs are cooler– mirror contamintion ?mirror contamintion ?

Interim cross-cal. resultsInterim cross-cal. results




ESACESACSAS-6.1 : effect of new pn RMF (1)SAS-6.1 : effect of new pn RMF (1)

H1426+428, rev278, single MOS/OM power-law model

SAS 6.0 SAS 6.1




ESACESACH1426: new pn rmf residualsH1426: new pn rmf residuals

Strange residuals shape below 0.6 keV but could be due to a CTI/gain problem at low energies hence residuals around the O-edge.




ESACESACSAS-6.1 : effect of new SAS-6.1 : effect of new pnpn RMF (2) RMF (2)

SAS-6.0

PKS 2155-504, rev 545

SAS-6.1

• Same 0.5 keV non-physical dip of pn residuals • combined fit is possibly the “truth” ?

M.Kirsch M.Kirsch




ESACESACSAS-6.1 : effect of new pn RMF (3)SAS-6.1 : effect of new pn RMF (3)

• Another case of Another case of “0.5 keV dip” on a “0.5 keV dip” on a continuum spectrum continuum spectrum

• black : MOS1black : MOS1• Red: pn SAS-6.0Red: pn SAS-6.0• Green: pn SAS-6.1Green: pn SAS-6.1

R. Saxton




ESACESACH1426 second revisitH1426 second revisit

Although the increasing Although the increasing pn/MOS discrepancy could pn/MOS discrepancy could be attributed to MOS …be attributed to MOS …

MOS seem to have the MOS seem to have the right spectral slope at low right spectral slope at low energies even in late revsenergies even in late revs

Assuming a single power-Assuming a single power-law from UV to soft X-raylaw from UV to soft X-ray




ESACESAC

R. Saxton

Early mission : no excess ?Early mission : no excess ?

• MS0737.9+7441 MS0737.9+7441 (BL Lac)(BL Lac)• rev.63rev.63 (Cal/PV) (Cal/PV)

• Best fit MOSs Best fit MOSs model: wabs *powermodel: wabs *power

• very nice very nice agreement overallagreement overall

• No excess of pn wrt No excess of pn wrt to MOS at low to MOS at low energies energies (pn/MOS=0.95 ! )(pn/MOS=0.95 ! )




ESACESACVery soft sourcesVery soft sources

RXJ 1856

• pn exhibits a strong excess attributed to pile-up from photons below detection threshold.• MOS agree well with Chandra (nH, kT)

• EPIC-pn cannot be EPIC-pn cannot be used on very soft used on very soft sourcessources




ESACESACExtremely soft sourcesExtremely soft sources

GD153, White Dwarf, kT=25eV, maximum below detection threshold

• OM-MOSs can be fitted with a WD SED model• EPIC-pn displays an excess by a factor 2 in the range 0.2-0.3 keV.




ESACESACBright (extended) galaxy clusterBright (extended) galaxy cluster

• Good combined fit overall

• 0.5-1 keV : ~ 10% pn excess (or MOS deficit)

• above 3keV : >10% MOS excess

• pn residuals at Fe-K (CTI or gain)




ESACESACHot Compact high-z clusterHot Compact high-z cluster

• Rather good combined fit (but lower statistics)

• 0.5-1 keV : about 15% pn excess(or MOS deficit)

MOS1: kT=15 keVMOS2: kT=12 keVpn : kT=10 keV




ESACESACMOS vs EPIC-pnMOS vs EPIC-pn

Why MOSs -the apparently varing Why MOSs -the apparently varing instrument- is making good or better fits instrument- is making good or better fits than EPIC-pn -the constant instrument - on than EPIC-pn -the constant instrument - on various types of objects/spectras at any various types of objects/spectras at any epoch ?epoch ?




ESACESACNewton/Chandra cross-cal.: PKS2155Newton/Chandra cross-cal.: PKS2155

Rev 362 Rev 545

• LETG agrees very well with MOSs• pn low-energy excess higher in rev.545

Model: wabs*bknpowerBest fit: MOSs




ESACESACNewton/Chandra cross-cal.: 3C273 (1)Newton/Chandra cross-cal.: 3C273 (1)

Rev.277




ESACESAC

Rev.655

EPIC-pn excess also higher with time

MOS/LETG agreement excellent.

Newton/Chandra cross-cal.: 3C273 (2)Newton/Chandra cross-cal.: 3C273 (2)




ESACESACNewton/Chandra cross-cal.Newton/Chandra cross-cal.

MOSs agree very well with Chandra (LETG, MOSs agree very well with Chandra (LETG, HETG & HRC)HETG & HRC)

RGSs too low in 0.3-0.5 keVRGSs too low in 0.3-0.5 keV

EPIC-pn too high at E < 1 keV wrt too all EPIC-pn too high at E < 1 keV wrt too all other instruments.other instruments.




ESACESACZeta Puppis wide cross-correlationZeta Puppis wide cross-correlation

Assuming zeta Assuming zeta Puppis is a stable Puppis is a stable source…source…

All measurement All measurement agree except pn agree except pn SAS-6.0SAS-6.0




ESACESACRGS low-E effective areaRGS low-E effective area

• Effective area correction of up to 20% below 0.5 keV suggested by a statistical analysis of BL Lacs (Pollock)

• It is unavoidable to be fudged.

•The exact function will be based on upcoming Crab observation (special set-up)

• This will bring MOSs and RGSs in very good agreement on the whole RGS energy range




ESACESACMOS low-E redistributionMOS low-E redistribution

Still too much redistribution at low energies ?




ESACESACEPIC high-E discrepancyEPIC high-E discrepancy

•MOSs return higher fluxes than pn above 3 keV

• F5-10 keV (MOS) higher than F5-10 keV(pn) by 10-15%

• MOS1 > MOS2 > pn

MOS (MOS1) finds always

•Harder spectra (AGNs)•Hotter temperature (galaxy clusters)




ESACESACLow-energy statusLow-energy status

A MOS/RGS deficit wrt EPIC-pn is developing with time at low A MOS/RGS deficit wrt EPIC-pn is developing with time at low energies (<1keV) increasing by up to 10% apparently due to energies (<1keV) increasing by up to 10% apparently due to a loss of flux from MOS/RGSa loss of flux from MOS/RGS Was there a deficit a launch ?Was there a deficit a launch ? Did the trend accelerate after cooling ?Did the trend accelerate after cooling ? Is it due to the MOS on-axis degraded response Is it due to the MOS on-axis degraded response

(“patch”)?(“patch”)? If due to contamination why at same rate for MOSs & If due to contamination why at same rate for MOSs &

RGSs ?RGSs ?

Why Chandra agree better with MOSs at any epoch ?Why Chandra agree better with MOSs at any epoch ?

On very soft sources pn shows a strong excessesOn very soft sources pn shows a strong excesses EPIC pn cannot be used for very soft sourcesEPIC pn cannot be used for very soft sources To what extent bright & soft (To what extent bright & soft ( >1.7) AGNs are affected ? >1.7) AGNs are affected ?




ESACESACXMM-Newton cross-cal. : To doXMM-Newton cross-cal. : To do

Document current status with SAS-6.1Document current status with SAS-6.1 Extend the statistical analysis on AGNsExtend the statistical analysis on AGNs

– Investigate possible flux/mode and spatial Investigate possible flux/mode and spatial dependence and spatial of MOS/pn relative dependence and spatial of MOS/pn relative calibration.calibration.

– EPIC-pn redistribution EPIC-pn redistribution NRCOs:NRCOs:

– Hz43 : comparison with early rev.89 obs. (June 2005)Hz43 : comparison with early rev.89 obs. (June 2005)– H1426+428 simultaneously with FUSE (June 2005 )H1426+428 simultaneously with FUSE (June 2005 )

Fudge RGS effective area below 0.55 keVFudge RGS effective area below 0.55 keV Need for a change of boresight for MOSs ?Need for a change of boresight for MOSs ?




ESACESAC

The End




ESACESACH1426+428, rev852, pn fitH1426+428, rev852, pn fit

Bruno Altieri EPIC Calibration meeting, Feb. 1-3, 2005 European Space Astronomy Centre Page 1...

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