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XMM­Newton CCF Release Note
XMM­CCF­REL­324
EPIC MOS HK GTI Selection
M.J.S. Smith
February 2, 2015
1 CCF Components
Name of CCF VALDATE EVALDATE Blocks XSCS
Changed Flag
EMOS1 HKPARMINT 0011.CCF 2014­11­06T15:15:00 2014­12­23T20:55:00 HKPARMINT NO
EMOS2 HKPARMINT 0010.CCF 2014­11­06T15:15:00 2014­12­23T20:55:00 HKPARMINT NO
2 Changes
During the 2014 winter eclipse season, gaps in ground station coverage around perigee resulted in
delays in stabilising to the nominal MOS focal plane (FP) temperature. As a consequence, during
this period most MOS exposures at the start of the science windows were subject to periods of
higher than nominal FP temperature before the normal operating temperature was reached and
maintained. A list of a#ected observations is given in Table 1. The duration of these periods varies
from exposure to exposure, but is typically of the order of 3 ks, and up to 4.8 ks for MOS1 and 3.8
ks for MOS2.
Science data collected during these periods should be filtered out through SAS data processing
for two reasons:
. the calibration impact, especially on the energy scale, of the temperature excursions is not
well established;
. in many cases, the high temperature period gives rise to a substantial number of hot pixels
or columns which subsequently return to normal once the nominal FP temperature has been
1

XMM­Newton CCF Release XMM­CCF­REL­324 Page: 2
Revolution Observation ID
2731 0729160501
2732 0744370301
2733 0744370401
2734 0741033901
2735 0745010401
2736 0742820201
2737 0745120101
2738 0743910301
2739 0744220701
2740 0745010301
2742 0744040301
2743 0744040401
Revolution Observation ID
2744 0744490401
2745 0744220301
2746 0744413101
2747 0722480201
2748 0743010401
2749 0744490601
2750 0741031401
2751 0745320101
2752 0741031501
2753 0744440101
2754 0744440201
Table 1: List of observations a#ected by non­nominal MOS FP temperatures at the start of the
exposure.
reached. However, standard SAS processing will remove associated events from the whole
exposure, leading to an unnecessary loss of good data.
The current filtering based on FP temperature housekeeping data (parameters E1253, K1253)
using an accepted range of [­125.0:­115.0] # C is too wide to e#ectively filter these cases. Hence this
pair of CCFs (one per MOS unit) has been created with a narrower FP temperature tolerance of
[­125.0:­120.0] # C to handle these cases. The validity of these CCFs is limited to the 2014 winter
eclipse season (revolutions 2731 to 2754, roughly early November to late December).
3 Scientific Impact and Estimated Quality
The new CCFs were tested on all MOS observations taken during the 2014 winter eclipse season.
The reduced temperature range upper limit e#ectively allows flagging and subsequent filtering of
the non­nominal FP temperature periods at the start of a#ected exposures. Once the nominal FP
temperature has been reached, it is maintained at a very stable level and remains within the new
tolerance. In particular, it was verified that:
. exposures a#ected by non­nominal FP temperature were correctly filtered up to the point that
the nominal temperature was reached;
. from that point onwards, the new temperature range tolerance did not result in any additional
filtering;
. exposures which were not a#ected by non­nominal FP temperatures did not undergo any
additional filtering due to the new FP temperature tolerance.
Additionally, compared with the use of the old CCFs, the new CCFs result in a reduced number of
bad pixels and columns being flagged for many of the a#ected exposures.

XMM­Newton CCF Release XMM­CCF­REL­324 Page: 3
4 Test Procedures
Verification of functionality with SAS 14.0: calview, cifbuild, emproc.
5 Expected Updates
Ground station coverage gaps during future eclipse seasons could give rise to temperature excursions
which would have to be handled in a similar manner. However, operational changes are currently
being developed with the aim to minimise the impact of such occurrences.