EPIC Chandra EPIC Chandra Cross Calibration Cross Calibration

with the with the PerseusPerseus ClusterCluster

S. S. MolendiMolendi, F. , F. GastaldelloGastaldello & & A.TiengoA.Tiengo(IASF(IASF--MI)MI)

Cross Cal with ClustersCross Cal with Clusters

•• Has enjoyed some successHas enjoyed some success

•• PerseusPerseus is the brightest cluster in the Xis the brightest cluster in the X--ray skyray sky

•• Lots of photons and no pileLots of photons and no pile--up!up!

•• In the past used to check In the past used to check pnpn/MOS cross /MOS cross calibrationcalibration

Example of old Example of old vsvs new new pn/mospn/mosResiduals in the form of ratio data/model Residuals in the form of ratio data/model for PN data on MOS best fitting model for PN data on MOS best fitting model

Example of old Example of old vsvs new new pn/mospn/mosResiduals in the form of ratio data/model Residuals in the form of ratio data/model for PN data on MOS best fitting model for PN data on MOS best fitting model

ACIS S3 ACIS S3 vsvs EPIC EPIC pnpn

•• Same thing, only now we compare Chandra ACIS Same thing, only now we compare Chandra ACIS

S3 with EPIC S3 with EPIC pnpn

•• About 3About 3××101066 events for each spectrum events for each spectrum extracted from annulus with bounding radii of 1' and 2 extracted from annulus with bounding radii of 1' and 2 ‘‘

•• Used old and new Chandra calibrations Used old and new Chandra calibrations (CALDB 4.1.1 with hrmaD1996(CALDB 4.1.1 with hrmaD1996--1212--20axeffaN0008.fits)20axeffaN0008.fits)

•• Multi T spectral model (Multi T spectral model (MolendiMolendi & & GastaldelloGastaldello 09)09)

ACIS S3 ACIS S3 vsvs EPIC EPIC pnpnResiduals in the form of ratio data/model for Residuals in the form of ratio data/model for pnpnand ACIS data on and ACIS data on pnpn best fitting model.best fitting model.

RenormRenorm applied to match spectra at 1.5 applied to match spectra at 1.5 keVkeV

pnpn

ACIS S3ACIS S3

ACIS S3 ACIS S3 vsvs EPIC EPIC pnpnResiduals in the form of ratio data/model for Residuals in the form of ratio data/model for pnpnand ACIS data on and ACIS data on pnpn best fitting model.best fitting model.

RenormRenorm applied to match spectra at 1.5 applied to match spectra at 1.5 keVkeV

pnpn

ACIS S3ACIS S3

Cross CalCross Cal

pnpn and ACIS S3 and ACIS S3 spectralspectral shapesshapes are are nownowin in muchmuch betterbetter agreement! agreement!

CongratulationsCongratulations calibratorscalibrators!!

Flux crossFlux cross--calcal•• BothBoth figuresfigures havehave renormrenorm factorsfactors: 5% : 5% forfor the the first; 15% first; 15% forfor the the secondsecond: : letlet’’s take s take themthem out.out.

Flux crossFlux cross--calcal•• BothBoth figuresfigures havehave renormrenorm factorsfactors: 5% : 5% forfor the the first; 15% first; 15% forfor the the secondsecond: : letlet’’s take s take themthem out.out.

Flux crossFlux cross--calcal•• BothBoth figuresfigures havehave renormrenorm factorsfactors: 5% : 5% forfor the the first; 15% first; 15% forfor the the secondsecond: : letlet’’s take s take themthem out.out.

Flux crossFlux cross--calcal

•• The new HRMA The new HRMA calibrationcalibration impactsimpacts on the on the ACIS/EPIC ACIS/EPIC fluxflux cross cross calibrationcalibration..

•• OurOur analysisanalysis indicatesindicates thatthat the the fluxflux cross cross calibrationcalibration belowbelow ~ 2 ~ 2 keVkeV willwill bebe shiftedshifted bybyaboutabout 10%. 10%.

•• AlthoughAlthough comparingcomparing spectraspectra extractedextracted fromfrom a a givengiven regionregion of a of a clustercluster maymay notnot bebe the best the best way way toto go, go, ourour data data indicatesindicates thatthat the the fluxfluxcross cross calibrationcalibration changechange isis notnot forfor the the betterbetter..

SummarySummary

•• The new HRMA The new HRMA effectiveeffective area limits area limits ACIS S3 ACIS S3 vsvs pnpn residualresidual calibrationcalibration errorserrorstoto lessless thanthan 5%5%

thisthis isis no no smallsmall achievementachievement!!•• The new The new spectralspectral calibrationcalibration modifiesmodifies bybyaboutabout 10% 10% ChandraChandra fluxesfluxes belowbelow 2 2 keVkeV, , ACIS ACIS vsvs EPIC EPIC fluxflux cross cross calibrationcalibration willwillbebe affectedaffected