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XMM-Newton Status Report - April 2005

XMM-Newton Status Report - April 2005

Mission StatusXMM-Newton operations continue to run smoothly with the exception of an anomaly in one of the EPIC MOS cameras. On 9 March XMM-Newton registered an event in the focal plane of the EPIC MOS1 instrument. The characteristics of the event were reminiscent of very similar events registered in the EPIC cameras at an earlier point in the mission, which were attributed to micrometeoroid impacts scattering debris into the focal plane.

It seems likely that MOS-1 CCD-6, one out of the six peripheral CCDs of MOS-1, will not be usable for scientific observation in future. Evidence of a limited number of new hot pixels elsewhere in the MOS1 focal plane was also recorded. These other effects are relatively minor. Scientific observations are continuing normally with XMM-Newton, including MOS1, but with CCD6 switched off. Investigations are underway to fully characterise changes in the instrument status. For the scientific output of the mission it is important to realize that MOS-1 is operated in parallel with the MOS-2 and the pn cameras. Therefore, the area on the sky that is no longer covered by CCD-6 is still covered by the remaining two cameras. The net effect of the loss of CCD-6 is therefore limited to only 3% of the total grasp of EPIC.

The ground segment is now being run with SCOS-1b and SCOS-2000 in parallel. On 14 April, a review will be held where the final switchover date to fully operate on SCOS-2000 will be determined.

Operations and archiving

The completion status of the observing programme is as follows:

  • Guaranteed time 100.0 %
  • AO-1 programme 100.0 %
  • AO-2 programme 99.9 %
  • AO-3 programme 92.0 %
  • AO-4 programme 4.6%

The AO-4 observations have been started slightly ahead of time, largely for sky visibility reasons.

Several Targets-of-Opportunity and Discretionary Time targets were observed, namely M101, HS0220+0603, V1118 Ori (two observations), GRB 050223, GRO J1655-40 (increase of allocated time), SGR 1806-20 and GRB 050326.

The XMM-Newton Science Archive (XSA) has 1420 registered external users as of 1 April. The monthly usage can be characterized through the following numbers for March 2005: in total about 1200 separate data sets were downloaded by 115 external users.

D/SCI appointed Dr. M. Arnaud as the new chairperson of the XMM-Newton Users' Group. She will replace Prof. J. Schmitt in autumn 2005. D/SCI also appointed Prof. B. McBreen as the new chairperson of the Observing Time Allocation Committee (OTAC). He succeeds Prof. M. Longair who chaired the review process for XMM-Newton AO-1 through AO-4.

Science highlights

ApJ accepted a letter by C. R. Mullis et al. on the discovery of a massive, X-ray-luminous cluster of galaxies at z=1.393, which is the most distant (X-ray-selected) cluster found to date. XMMU J2235.3-2557 was serendipitously detected as an extended X-ray source in an archival XMM-Newton observation. VLT-FORS2 R and z band snapshot imaging reveals an over-density of red galaxies in both angular and colour spaces coincident in the sky with the X-ray emission. Subsequent VLT-FORS2 multi-object spectroscopy unambiguously confirms the presence of a massive cluster based on 12 concordant redshifts in the interval 1.381 cluster found with XMM-Newton, the relative ease and efficiency of the discovery demonstrates that it should be possible to build large samples of z>1 clusters through the joint use of XMM-Newton and large, ground-based telescopes.

In total 795 papers – either completely or partly based on XMM-Newton observations – had been published in the refereed literature before 1 April.

Last Update: 1 September 2019
23-May-2024 02:58 UT

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