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XMM-Newton CCF Release Note
XMM-CCF-REL-174
pn telescope eective area modication
M. Kirsch
June 9, 2004
1 CCF components
Name of CCF VALDATE List of Blocks
changed
CAL VERSION XSCS ag
XRT3 XAREAEF 0009 2000-01-13T00:00:00 ONAXISXAREAEF 3.169 NO
2 Changes
XMM EPIC-pn observations with very high statistic show residuals at the Silicon edge around 1.8
keV and gold edge around 2.2 keV (see Figure 1). The gold edge feature can be explained by not
perfect calibration of the telescope eective area.
Figure 1: MCG{6-30-15 with features due to not perfect calibration at 1.8 and 2.2 keV
1

XMM-Newton CCF Release XMM-CCF-REL-174 Page: 2
The eective area around the gold edge has been changed in order to improve the residuals
around that edge in the pn-spectra.
2.1 ONAXISXAREAEF
Using the obtained in-orbit data on continuum sources ( at around the edges) is the best way to
calibrate the eective mirror areas across the edges. Since the XRT areas were already once updated
(based on MOS results) from CCF 0007 to 0008, a further update (now based on spectra with very
high statistics from several sources) is justied. Such an update is not necessarily required for all 3
XRTs as they might not be identical at this level of accuracy (contamination can drastically alter
the re ectivity at the edges).
New values delivered from MPE (F. Haberl) have been implemented. Figure 2 shows the history
of telescope eective area changes.
Figure 2: Eective area of the on telescope. Black: XRT3 XAREAEF 0007.CCF red:
XRT3 XAREAEF 0008.CCF, green: XRT3 XAREAEF 0009.CCF

XMM-Newton CCF Release XMM-CCF-REL-174 Page: 3
3 Scientic Impact of this Update
The change will reduce residuals around the gold edge for all modes. Figure 2 shows spectra of the
black hole candidate MCG{6-30-15 from revolutions 301+302+303 (merged) with old and new CCF
which best illustrates the improvement.
Note that the still present residuals around the silicon edge have been modeled by a narrow
absorption line in order to be able to adjust the residuals around the gold edge better.
Figure 3: MCG{6-30-15: upper with XRT3 XAREAEF 0008.CCF lower: with
XRT3 XAREAEF 0009.CCF

XMM-Newton CCF Release XMM-CCF-REL-174 Page: 4
4 Estimated Scientic Quality
This change will improve the tting quality for data with very high statistics, where the residuals
for gold do appear of course stronger than for data with lower statistics.  2 values for MCG{6-30-15
improve as follows:
 single powerlaw:  2 = 1192=579 = 2:06
 powerlaw+gauss (in order to model silicon feature):  2 = 872=577 = 1:51
 powerlaw+gauss with new telescope eective area:  2 = 764=577 = 1:32
5 Test procedures & results
The CCF has been tested on the MCG{6-30-15 data and on various other sources.
6 Expected Updates
The still present residuals around the silicon edge need to be understood can however not be im-
proved further with the telescope eective area, since that feature seems to be related to the actual
CCDs.