XMM-Newton-NEWS

XMM-Newton-NEWS #43, 01-Dec-2004

XMM-Newton Science Operations Centre at
ESA's European Space Astronomy Centre,
P.O. Box - Apdo. 50727, 28080 Madrid, Spain

SOC Home Page:	https://www.cosmos.esa.int/web/xmm-newton/
Helpdesk web interface:	https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk
Helpdesk email address:	xmmhelp@sciops.esa.int
News Mailing List:	https://www.cosmos.esa.int/web/xmm-newton/newsletter

Version 6.1.0 of the Science Analysis System (SAS) released

http://xmm.esac.esa.int/external/xmm_sw_cal/sas_frame.shtml

The main improvements in this release can be summarized as follows:

General

The main changes introduced in this version with respect to SAS 6.0.0 are:

an RGS background modelling capability. This is explained further below in the RGS section of this note,
an upgrade of the OM grism data analysis, explained further below in the OM section,
a new, experimental treatment of Time Correlation is included in SAS 6.1. The new treatment corrects known problems with existing time correlation data using Reconstructed Time Correlation (TCX) data. It should be noted that the validation of the TCX files in the ODF (see below) and their use in the SAS is still being validated and as such, experimental.

All other changes to SAS were either bug fixing or better handling of calibration algorithms.

In addition, a small change has been introduced in the startup command files sas-setup.(c)sh: the internal save directory $HOME/.sas.d is no longer part of the SAS_PATH environment variable. This should avoid the problem of users getting pre-established selection choices without knowing it, because of saved parameters in former SAS sessions. A SAS user who wants to use a saved configuration (see SAS GUI documentation) has now to consciously add this directory to the SAS_PATH.

EPIC

MOS specific:

epatplot calculations corrected
correct response calculations for imaging mode data in Timing Mode observations

PN specific:

redistribution function upgraded (especially at low energies), in better agreement with results from ground calibration
added Extended Full Frame mode tuning function for CTI correction

RGS

An alternative method for determining the background spectrum has been implemented, based on RGS background templates obtained from empty-field observations. The whole method is described in XMM-SOC-CAL-TN-0058 "Templates for the RGS Background", by R. Gonzalez-Riestra. The technical note includes test results of the new method, which is especially important for the analysis of extended sources.

OM

OM grism data processing has changed substantially. The output products have been simplified, making them more usable and understandable.

CCF

Please notice that a number of new calibration constituent files (CCFs) have been released together with SAS 6.1.0, which are necessary for running some of the tasks. You can follow the CCF download instructions at

http://xmm.esac.esa.int/external/xmm_sw_cal/calib/ccf.shtml

Data processing facilities in the XMM-Newton Science Archive (XSA)

As of XSA v2.7, released at the beginning of November 2004, a full suite of data processing facilities can be triggered from the XSA user interface:

reprocessing of raw telemetry (ODF) data for all XMM-Newton cameras through the latest public SAS data reduction meta-tasks ("emproc", "epproc", "rgsproc", "omichain", "omfchain"). After completion of processing, output products are stored in an ftp area for retrieval, together with the Calibration Index File and the ODF summary file generated by the reduction.
filtering of EPIC calibrated and concatenated event lists prior to retrieval, according to standard "selectlib" expressions (cf. http://xmm.esac.esa.int/sas/current/doc/selectlib/)
interactive extraction of spectra and light curves from sky regions defined on EPIC exposure images in the XSA FITS viewer tool. Response matrices are generated together with spectral products. Again, data can be screened upon scientific products accumulation using data selection expressions such as in "xmm/evselect" or "especget". Output files are stored in an ftp area for retrieval after completion of processing.
the same interface allows users to interactively generate a full field-of-view EPIC time series.
filtering on high particle-background intervals can be applied to the interactive generation of EPIC spectra, or the screening of an event list. The filtering is applied by generating Good Time Intervals from the single-events, 10-s time-binned field-of-view, light curve. The minimum energy of the light curve (nominally 10 keV) and the count rate threshold applied (nominally 0.35 cts/s and 1.0 cts/s for the MOS and the pn, respectively) are customizable by the user.

These facilities are intended to complement the high-level (PPS) scientific products generated by the Survey Science Centre for all XMM-Newton observations, and the 1XMM Catalog of EPIC Serendipitous Sources. Both these resources are stored within the XSA, and can be browsed through its user interface on a large number of querying parameters.

Users are strongly encouraged to use these facilities. Opinions on these new functionalities, as well as suggestions as to how they could be improved are welcome, and should be conveyed, as usual, through the XMM-Newton Helpdesk.

Finally, we recall that users can now monitor the status of their shopping basket download or data processing requests through a "Request Monitor" tool, which can be launched via a button in the top panel of the XSA user interface.

A short "guided tour" of the XSA is available at the following URL:
http://xmm.esac.esa.int/external/xmm_data_acc/xsa/docs/tour.shtml

together with a list of "how-to" Frequently Asked Questions:
http://xmm.esac.esa.int/external/xmm_data_acc/xsa/docs/xsa_faq_usage.shtml

Changes to the Observation Data Files (ODF)

The XMM-Newton SOC is currently re-finalizing and checking all produced ODFs preparatory to systematic regeneration of all pipeline products using the latest SAS capabilities.

This process started on 15th May 2004 and consists of:

Updating the Attitude data in an existing ODF with the latest re-generated Attitude information (always updated).
Adding the Raw Attitude File (RAF) to existing ODFs (always added).
Adding the corrected Time Correlation information (TCX) to existing ODFs (always added).
Adding RGS offset files to existing ODFs (optionally added).
Adding PN offset data image files to existing ODFs (added when available).
Checking the Data Quality (ODF check) of the re-finalized and new ODFs.

The additional files are described in the latest version of the XMM-Newton Data Files Handbook, which is available at:
http://xmm.esac.esa.int/external/xmm_user_support/documentation/

Further, and after the addition of the above information, each re-finalized or newly produced ODF is being passed at the SOC through a Data Quality checking process (ODF-check). This process extracts information about the ODF that may occasionally lead to special handling of problem ODFs prior to their delivery to SSC for Pipeline generation. This quality information will be made available to XSA users.

So far, existing ODFs from revolutions in the range 385 to 710 have gone through the re-finalization and ODF-check processes. ODFs for revolutions 800 and up have been similarly processed. Please, be aware that PN offset dumps have been added (when available) to ODFs taken before revolution 832. From revolution 833 onwards the PN offset dumps are already part of the Observation.

To recognize whether an ODF has gone through the add-on and Quality Check processes you may check the files listed in the SUM.ASC ODF constituent. The presence of a file named ...RAS.ASC will be the confirmation that the ODF has gone through both processes.

XMM-Newton EPIC background products updated

Recent additions have been made to the XMM-Newton EPIC background products at Birmingham University - XMM-Newton background events files for the 3 EPIC instruments in their different instrument mode/filter combinations have been constructed using a superposition of many pointed observations. These 'template Background' files are especially useful in the analysis of large or extended sources, and can be found at:
http://www.sr.bham.ac.uk/xmm3/BGproducts.html

together with related software, details about their construction and some guidance as to their usage. Recent additions include new THICK filter background event datasets and exposure maps for PN (full frame and extended full frame), MOS1 and MOS2 (full frame mode).

Yours sincerely,
XMM-Newton SOC