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GSFC XMM-Newton GOF Status Report #096: XMM-NEWTON NEWS #43
_/ 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:
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News Mailing List:
- Version 6.1.0 of the Science Analysis System (SAS) released
- Data processing facilities in the XMM-Newton Science Archive (XSA)
- Changes to the Observation Data Files (ODF)
- XMM-Newton EPIC background products updated
Version 6.1.0 of the Science Analysis System (SAS) released
The main improvements in this release can be summarized as follows:
* 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
- 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
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.
- epatplot calculations corrected
- correct response calculations for imaging mode data in Timing Mode
- 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
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 grism data processing has changed substantially. The output products have
been simplified, making them more usable and understandable.
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
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.vilspa.esa.es/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
A short "guided tour" of the XSA is available at the following URL:
... together with a list of "how-to" Frequently Asked Questions:
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
- 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:
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
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:
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).
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