1. Evaluation of the EPIC flux cross-calibration from 2XMM sources R. Saxton, S. Mateos, A. Read, S. Sembay Mateos et al., 2009, A&A, arXiv.0901.4026

2. 2XMM sources

3. pn vs MOS1 energy dependence MOS1 vs MOS2 energy dependence Distributions of flux ratios fitted with Gaussian profiles:

4. pn vs MOS1:energy dependence pn / MOS agreement worse above ~4.5 keV (12.5%) ~constant offset from MOS cameras of 7-9% from 0.5-4.5 keV pn / MOS agreement better than 3% in 0.2-0.5 keV band 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV

5. MOS1 vs MOS2:energy dependence MOS cameras agree to better than 4% at all energies 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV

6. pn vs MOS1:time dependence MOS to pn flux cross-calibration ~constant >0.5 keV strong dependence on time <0.5 keV: evolution of the MOS RMF with time

7. MOS1 vs MOS2: time dependence MOS flux cross-calibration ~constant at all energies

8. pn vs MOS1:offaxis dependence 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV Variations of MOS vs pn relative flux calibration vs offaxis ARF effect:  QE: spatial variation in QE offaxis (MOS and pn)  Vignetting: General vignetting function  PSF: Uncertainties in offaxis PSF

9. MOS1 vs MOS2:offaxis dependence Variations of MOS relative flux calibration vs offaxis ARF effect:  QE: spatial variation in QE offaxis (MOS and pn)  Vignetting: General vignetting function  PSF: Uncertainties in offaxis PSF 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV

10. 1 2 3 4 1 2 3 4 Azimuthal dependence - PN v MOS-2 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV Strong azimuthal-angle dependence at high energies

11. 1 2 3 4 1 2 3 4 RGA obscuration: Azimuthal dependence Excluded sources at offaxis<2 arcmin 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV Sources divided in 4 azimuthal angle bins based on DETX/DETY coordinates Strong azimuthal angle dependence at high energies Sources lying along the RGA dispersion axis show a large gradient in relative flux Calibration of RGA blocking factor incorrect at high energies? B-4 B-5

12. 1 2 3 4 1 2 3 4 RGA obscuration: Azimuthal depencence Strong azimuthal angle dependence at high energies Sources lying along the RGA dispersion axis show a large gradient in relative flux Calibration of RGA blocking factor incorrect at high energies? Excluded sources at offaxis <2 arcmin 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV Sources divided in 4 azimuthal angle bins based on DETX/DETY coordinates B-5 B-4 B-5B-4 B-5

13. Current azimuthal vignetting factor for MOS-1 1.5 keV @ 9 amin offax 9 keV @ 9 amin offax

14. 1 2 3 4 1 2 3 4 Low-energy azimuthal dependence: MOS-1 Strong azimuthal angle dependence at low energies Sources lying on CCDs from different batches show a large gradient in relative flux Excluded sources at offaxis< 2arcmin 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV Sources divided in 4 azimuthal angle bins based on DETX/DETY coordinates B-5 B-4 B-5B-4 B-5

15. 1 2 3 4 1 2 3 4 Excluded sources at offaxis<2 arcmin 1:0.2-0.5 keV 2:0.5-1 keV 3:1-2 keV 4:2-4.5 keV 5:4.5-12 keV Sources divided in 4 azimuthal angle bins based on DETX/DETY coordinates Smallish azimuthal angle dependence at low energies. Batch effect not so strong here ? B-4 B-5 Low-energy azimuthal dependence: MOS-2

16. Consistent improvements in the MOS2/pn flux ratio, with some evidence for similar improvements for MOS1/pn Large scatter, low stats at very lowest energy so far

17. Conclusions Excellent agreement of the two MOS cameras (<4%) at all energies MOS cameras register 7-9% higher flux than pn below 4.5 keV 10-13% flux excess at the highest energies No evolution of flux ratios with time except in the 0.2-0.5 keV band Gradual degrading of the MOS redistribution function MOS to pn excess increases with offaxis: ARF effect Strong dependency of MOS to pn excess 4.5-12 keV flux on azimuthal-angle

18. TO DO Fudge RGA obscuration to give larger azimuthal effect for MOS’s at high energies ? Use SCISIM to justify physical parameters ? Put in a batch-specific, low-energy QE contribution for MOS- CCDs ? 2XMM could benefit from: - MOS RMFs made spatially, temporally dependent. - EBG PSF ? - Spectral dependence in flux calculation Strong dependency of MOS to pn excess 4.5-12 keV flux on azimuthal-angle Calibration of RGA blocking factor (RGA absorption) incorrect at high energies?