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EPIC flux comparison from 2XMM sources

EPIC flux comparison from 2XMM sources. S. Mateos, R. Saxton, S. Sembay & A. Read. Sources Used. Point-like sources from 2XMM detected in 2+ cameras > 200 counts in each camera Off-axis angle 0-12 arcmins F 2-10 > 6E-12 have been excluded to avoid pile-up effects.

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EPIC flux comparison from 2XMM sources

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  1. EPIC flux comparisonfrom 2XMM sources S. Mateos, R. Saxton, S. Sembay & A. Read

  2. Sources Used • Point-like sources from 2XMM detected in 2+ cameras • > 200 counts in each camera • Off-axis angle 0-12 arcmins • F2-10> 6E-12 have been excluded to avoid pile-up effects

  3. Count rate – flux conversion Count rates converted to fluxes using energy conversion factors (ECF) which are based on a spectral model of an absorbed power-law with NH=3E20, slope=1.7 ECFs calculated using the detector matrices: MOS: On-axis RMF for revolution 375 + on-axis ARF PN: Latest, canned, on-axis, full-frame RMF for single and single+double events + on-axis ARF Count rates found with - MOS: pattern=0-12, PN: 0.2-0.5 keV, pattern=0; 0.5-12 keV, pattern=0-4

  4. PN v MOS-1: Band 3 (1-2 keV)

  5. PN v MOS-1: Band 1 (0.2-0.5)

  6. PN v MOS-1: Band 2 (0.5-1)

  7. PN v MOS-1: Band 4 (2-4.5)

  8. PN v MOS-1: Band 5 (4.5-12)

  9. PN v MOS-1: Flux comparison

  10. PN v MOS-2: Flux comparison

  11. MOS-1 v MOS-2: Flux comparison

  12. Flux Ratios (%) The Kirsch relation: mos = k * pn where k is an energy independent constant, ~1.05 – 1.08 CAL-TN-0052-5 (Stuhlinger et al. 2008)

  13. First Results • MOS cameras agree to better than 4% at all energies. • PN has a ~constant offset from MOS cameras of 7-9% from 0.5-4.5 keV • PN / MOS agreement much better (<3%) in 0.2-0.5 keV band • PN / MOS agreement worse at high energies at least for MOS-1 (12.5%)

  14. Low-Energy difference Why so good ?? Is the use of a single RMF ok ? Reminder: MOS flux conversion uses RMF for on-axis (i.e. on patch) at Rev 0375. PN: Uses on-axis (Y=9) RMF These approximations will mainly effect low energies.

  15. PN v MOS-1: Change with time

  16. PN v MOS-2: Change with time

  17. MOS-1 v MOS-2: Change with time

  18. PN v MOS-1: Off-axis angle Iufh Yth Tj Tyj e

  19. PN v MOS-2: Off-axis angle F F F

  20. Low-Energy summary • Ignoring sources which fall on the MOS patches, i.e. using Θ = 2 – 12 arcmins we get: (m1-pn)/m1 = 10 - 12% (m2-pn)/m2 = 2 - 7% Time variability makes these numbers unreliable but m2/pn looks to be less than ~8%

  21. PN v MOS-1: Flux comparison ?

  22. High-Energy difference (m1-pn) / m1=12.5%Why so high ?? Is the Kirsch relation wrong ??

  23. PN v MOS-1: Off-axis angle

  24. PN v MOS-2: Off-axis angle

  25. MOS-1 v MOS-2: Off-axis angle

  26. What depends on off-axis angle? • Vignetting (all cameras) • RGS obscuration (MOS) • PSF (all cameras) Azimuthal-angle dependent Azimuthal-angle dependent (MOS)

  27. MOS PSF A measure of the XMM PSFs, lighter colour means a sharper PSF.

  28. MOS CCDs 1 4 2 4 1 3 3 2 A measure of the XMM PSFs, lighter colour means a sharper PSF.

  29. PN v MOS-1: Azimuthal angle

  30. PN v MOS-2: Azimuthal angle

  31. Conclusions for MOS / PN • MOS = PN * 1.08 from 0.5 – 4.5 keV • With this analysis we can’t say what the relation is in the 0.2-0.5 keV band. • At high energies there is an extra off-axis angle, azimuthal-angle dependent effect which increases the MOS excess. This aligns with the RGS dispersion direction and probably means that the RGS absorption needs recalibrating.

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