1 / 15

Evaluation of the EPIC flux cross-calibration from 2XMM sources

This study examines the flux cross-calibration of EPIC cameras in 2XMM sources, analyzing energy and off-axis dependencies, as well as the effect of azimuthal angles and RGA obscuration. The results show discrepancies between MOS and pn cameras at different energies, suggesting the need for further calibration adjustments.

jtaber
Download Presentation

Evaluation of the EPIC flux cross-calibration from 2XMM sources

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Evaluation of the EPIC flux cross-calibrationfrom 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 Distributions of flux ratios fitted with Gaussian profiles: MOS1 vs MOS2 energy dependence

  4. pn vs MOS1:energy dependence 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 ~constant offset from MOS cameras of 7-9% from 0.5-4.5 keV pn / MOS agreement worse above ~4.5 keV (12.5%)

  5. MOS1 vs MOS2:energy 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 MOS cameras agree to better than 4% at all energies

  6. 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

  7. Azimuthal dependence - PN v MOS-2 1 4 2 4 1 3 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 3 2 Strong azimuthal-angle dependence at high energies

  8. RGA obscuration: Azimuthal dependence Excluded sources at offaxis<2 arcmin B-4 B-4 1 4 B-4 B-4 B-4 2 4 1 3 B-5 B-5 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 3 2 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?

  9. RGA obscuration: Azimuthal depencence Excluded sources at offaxis <2 arcmin 1 4 B-5 B-4 B-4 B-4 2 4 1 B-5 B-4 3 B-5 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 3 2 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?

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

  11. Low-energy azimuthal dependence: MOS-1 Excluded sources at offaxis< 2arcmin 1 4 B-5 B-4 B-4 B-4 2 4 1 B-5 B-4 3 B-5 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 3 2 Strong azimuthal angle dependence at low energies Sources lying on CCDs from different batches show a large gradient in relative flux

  12. Low-energy azimuthal dependence: MOS-2 Excluded sources at offaxis<2 arcmin B-4 B-4 1 4 B-4 B-4 B-4 2 4 1 3 B-5 B-5 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 3 2 Smallish azimuthal angle dependence at low energies. Batch effect not so strong here ?

  13. 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

  14. 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

  15. 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?

More Related