Status of the EPIC calibration

Transcription

1 Status of the calibration 16 October 2003 Marcus G. F. Kirsch Marcus G. F. Kirsch with the input of the whole consortium Page 1

2 progress in calibration general absolute timing problem seems to be solved robust SAS for -pn time jumps Vignetting: Possible offset of around <1 arcmin in the telescope axis from nominal for all cameras has been under investigation with different analysis methods. First results show an improvement. PSF: re-calibration MOS QE: epoch dependant QE files to accommodate apparent change in the oxygen edge RMF: epoch dependant redistribution parameter files to accommodate an apparent change in the low energy surface charge loss timing mode energy correction pn timing mode: soft flare screening spatial variation of the energy scale cross calibration Page 2

3 th. absolute accuracy OBT -pn 50 ms 30 ms orbit prediction 20 ms XMCS UTC 100 ms ms quadrant quadrant clocks quadrant clocks quadrant clocks clocks theoretical upper limit for absolute time uncertainties is <100 ms the limited number of analyses conducted so far indicated in the past that the actual error is larger (~1ms) Page 3

4 a. accuracy: the bug (for details see Kirsch et al. Proc. SPIE 5165) wrongly corrected CDMU delay ( µs) delay was erroneously subtracted instead of added --> shift of µs. correction will be implemented in new time correlation work around will be issued on -SOC pages UTC(OBT) = ERT + δ(cdmu) - δ(flight) - δ(g/s) Page 4

5 absolute timing with the Crab (for details see Kirsch et al. Proc. SPIE 5165) f_rad f_xmm MXP 1-MXP 1-MXP Orbit OBS ID [Hz] [Hz] [phase] [phase] [ ms ] absolute timing accuracy: ~ µs in agreement with Crab observations performed by RXTE and Chandra Crab observation with Chandra,, XMM and in the optical using an MPE developed fast photometer to get a radio-ephemeris independent phase solution between the optical and X-ray pulses performed, to be analysed Page 5

6 data anomalies (for details see Kirsch et al. Proc. SPIE 5165) pn-aux data anomalies : frequency of occurrence is varying unrelated to camera mode, observing time and/or duration random negative or positive jumps in FTCOARSE not found occasionally by SAS pulse peak broadening, phase shift spurious pulse components W. Becker M. Kirsch SAS 6.0 (spring 2004): refined detection/correction algorithm --> all problems should reliably found and corrected Page 6

7 Vignetting:the 4 methods source at different position diffuse background source elongation coma cluster Page 7

8 3C58 and G D. Lumb M. Kirsch Page 8

9 position of optical axis method MOS1 X MOS1 Y MOS2 X MOS2 Y PN X PN Y G (-) (-) Diffuse Background (-) Source Elongation (-) (-)340 (-) / /-300 Coma Cluster 110 +/-40 (-)200 +/ /-60 (-)1255 +/ / /-30 3C58 + G (-) (-) / /-500 detector co-ordinates (0.05 arcsec) Page 9

10 position of optical axis method MOS1 X MOS1 Y MOS2 X MOS2 Y PN X PN Y Coma Cluster 110 +/-40 (-)200 +/ /-60 (-)1255 +/ / /-30 3C58 + G (-) (-) / /-500 optics_x/y (PIXCOORD) optics_x/y MISC_ difference in pixel difference in arcsec currently under testing in DT SAS Page 10

11 calculate new BS angles the new optical axis position required a set of new Boresight CCFs which hold for each instrument a triple of three angles describing the misalignment of the respective instrument boresight with respect to the satellite coordinate frame using the OMC2/3 field new BS misalignment angles for all the three cameras have been calculated goal: astrometry should not change!!!!!!!!! Page 11

12 astrometry: : -2MASS old optical axis and BS: RA offset: arcsec DEC offset: arcsec RA offset: arcsec DEC offset: arcsec RA offset: arcsec DEC offset: arcsec new optical axis and BS RA offset: arcsec DEC offset: arcsec RA offset: arcsec DEC offset: arcsec RA offset: arcsec DEC offset: arcsec B. Altieri Page 12

13 3C58 results for MOSs Model: constant[1]*wabs[2]( powerlaw[3] ) 3C58 Vignetting check const norm in factor model mos1 mos2_old old mos1_new mos2_new mos2_old mos1_old mos2_new mos1_new M. Kirsch off axis observation angle in arcmin? M. Kirsch flux variation off axis reduced from ± 10 % down to ± 1-2 % for both MOSs pn to be checked with Coma/G observations Page 13

14 missing/finding the gap in order to recover properly the flux sources should not fall onto CCD gaps also the condition of the right off axis angle must be taken into account 8 observations have been optimised for that...one not enough Page 14

15 PSF: re-calibration photon index normalisation spectra from annuli at 0, 5, 10, 15,...40 pixels of MCG created appropriate RSPs and ARFs fit (power-law modelling) on the 2-10 kev single events. derived spectral slope for non-piledup point sources is not independent of the extraction radius extraction radius in pixels A. Read extraction radius in pixels Page 15

16 MOS: Low Energy Epoch Dependent Response Variation S. Sembay S. Sembay Significant change in spectrum between Rev 78 and 533/534 Page 16

17 what happened? S. Sembay S. Sembay RXJ , mos1 and mos2, in OPEN between Revolutions 175 and 622 no filters, so the CCDs have changed difference in the change in the spectrum below 200 ev for MOS1 and MOS2 combination of QE and rmf change which has affected both cameras, but not exactly at the same times Page 17

18 MOS: : oxygen absorption MOS1 old QE new QE MOS2 old QE new QE S. Sembay S. Sembay PKS MOS1 and MOS2 from Rev 450 showing the difference at oxygen of the old and new QE MOS2 fits pretty well, but MOS1 still has some residuals, probably due to inaccuracy in the new test rmf Page 18

19 M1-pn M2-pn M1-M2 MOS: : oxygen absorption old QE and rmf S. Sembay Rev new QE and test rmf Rev differences in fitted spectral slope to a group of AGN in the band kev all cameras now agree to within 0.05 in slope whereas the difference before between MOS and pn was ~0.15 Page 19

20 MOS: : Timing mode Timing_En/LW_En MOS LW versus Timing M. Kirsch LW Energy in kev MOS1 MOS2 black: LW red: Timing 1E in rev. 447 in LW and Timing mode for both cameras energy in Timing mode is overcorrected by up to 1.5 % differences between both MOSs in LW mode less than ~0.7 % differences between both MOSs in Timing mode less than ~0.5 % proposal: fix differences between LW and Timing mode with an energy dependent tuning function (as also successfully done for the pn) Page 20

21 pn: spectral response in SAS5.4.1 old 50 nm 25 nm new Now implemented (SAS5.4.1) newly determined thickness of the SiO 2 entrance window New Quantum Efficiency curve RX J : Redistribution re- adjustment F. Haberl Page 21

22 pn: : refined spectral redistribution RX J F. Haberl F. Haberl Page 22

23 pn: : PKS without and with new QE and redistribution for pn F. Haberl F. Haberl Page 23

24 pn: long term trends F. Haberl no change in soft response K. Dennerl CTE degradation seems to slow down (some further monitoring before action) Page 24

25 pn: the ventilation hole superposition of Vela SNR observations confirms the presence of energy shifts in a ring-like structure with a similar shape as the ventilation hole in the electronic board below the CCDs explanation: systematic deviations from exponential charge loss caused by optical/infrared light shining through the ventilation hole, which reduces the charge loss in this area due to partial saturation of traps F. Haberl special special CTI CTI correction, correction, not not for for SAS SAS K. Dennerl Page 25

26 pn: : soft x-ray flares V. Burwitz Flare duration ~ sec FIFO gap duration ~ sec found in all fast Timing mode observations most likely caused by heavy ions with high energies which appear as low energy events because of electronic saturation. hamper spectroscopy below ev annoying for soft bright sources bad for fainter soft sources Page 26

27 solution/improvement Only singles total spectrum flare spectrum clean spectrum. filter them out below 250 add additional Good Time intervals for the FIFO gaps a tool will be provided with the next SAS V. Burwitz Page 27

28 cross calibration: 3C273 Page 28

29 cross calibration: -RGS PKS AB Dor systematic cross calibration for 25 targets, 200 observations underway understand the up to ± 20% differences in flux between and RGS Page 29

30 calibration summary Effect Max. Error Energy dependent Off axis angle dependent Relative Astrometry 1 (r.m.s.) NO YES Absolute Astrometry 2 (r.m.s.) NO YES PSF 2 % YES YES Relative Effective Area ± 5 % YES YES Absolute Effective Area ± 10 % YES YES Line Energies ± 10 ev YES YES Relative Timing DP/P<10-8 NO NO Absolute Timing ms NO NO Page 30

31 main plans for the future general: Vignetting: verify pn with Coma and G data check astrometry on more observations (SSC) releasing BS CCFs and MISC_DATA (optical axis) PSF: re-calibration of the energy dependence of the PSF. At the moment the derived spectral slope for non-piled-up point sources is not independent of the extraction radius MOS: pn: epoch dependant QE files epoch dependant redistribution parameter files to accommodate an apparent change in the low energy surface charge loss implementing tuning function for timing mode energy shifts implementing low energy flare screening into SAS 6.0 releasing TIME_COR CCFs needed for new OAL in SAS 6.0 taking also special settings for EFF Mode for pn at the beginning of the mission into account Page 31

32 for detailed information Calibration Portal xmm.vilspa.esa.es/external/ /external/xmm_sw_cal/calib/index.shtml Updated: Calibration Status Version 2.2 for new SAS release Release notes for every new CCF General Calibration Documentation we keep on calibrating Page 32