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

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 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: keV, pattern=0; keV, pattern=0-4

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

PN v MOS-1: Band 1 ( )

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

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

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

PN v MOS-1: Flux comparison

PN v MOS-2: Flux comparison

MOS-1 v MOS-2: Flux comparison

Flux Ratios (%) Energy (keV)(m1-pn)/m1(m2-pn)/m2(m2-m1)/m ±0.60.9± ± ±0.18.4±0.20.8± ±0.29.4±0.20.3± ±0.26.7± ± ±0.49.0± ±0.3 The Kirsch relation: mos = k * pn where k is an energy independent constant, ~1.05 – 1.08 CAL-TN (Stuhlinger et al. 2008)

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

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 PN: Uses on-axis (Y=9) RMF These approximations will mainly effect low energies.

PN v MOS-1: Change with time

PN v MOS-2: Change with time

MOS-1 v MOS-2: Change with time

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

PN v MOS-2: Off-axis angle FFFFFF

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

PN v MOS-1: Flux comparison ?

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

PN v MOS-1: Off-axis angle

PN v MOS-2: Off-axis angle

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

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

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

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

PN v MOS-1: Azimuthal angle

PN v MOS-2: Azimuthal angle

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 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.