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GSFC XMM-Newton GOF Status Report #086: XMM-NEWTON NEWS #38
_/ XMM-NEWTON NEWS #38 --- 24-Mar-2004
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- Version 6.0.0 of the Science Analysis System (SAS) released
- 4th VILSPA SAS Workshop
- Conference Announcement: Exploring the X-ray Universe
Version 6.0.0 of the Science Analysis System (SAS) released
The main improvements of this release can be summarized as follows:
* a new task parameter interface has been implemented - this may necessitate
updating your current "old" scripts. See under parameter interface below.
* graphical user interfaces have been upgraded. In xmmselect it is now
to fix basic filtering criteria and derive from a reduced event list in
images, spectra, etc, without running over the whole event list. This makes
xmmselect much faster for most purposes. The Dataset Browser offers
a refresh button, for updating the content of the directories searched.
* adequate handling of the instrument optical axis. This improves the
vignetting correction significantly, even for on-axis sources.
* exposure maps now correctly reflect spatial effect of event flag
selection, and out-of-time and dead-time corrections are now applied. EPIC
source lists now have correct maximum likelihood values (in all previous
version these were >=2 times too large).
- blanking of bad-energy columns and correct handling as dead areas
- filtering and removal of flickering pixels, decreasing significantly
the noise at low energies.
- improvement in handling of MOS timing mode CTI.
- ebadpixupdate: New SAS tasks that allows manipulations of bad
pixels at the level of the calibrated events list
- epreject: New SAS task which corrects shifts in the energy scale of
specific pixels due to high-energy particles hitting the EPIC PN detector
during offset map calculation and suppresses detector noise at low energies
by statistical flagging events based on the known noise properties of the
lowest energy channels. In the case of timing mode data, flagging of soft
flare events may be performed.
- epatplot: The optional input of a background eventset now allows the
determination of background-subtracted pattern fractions. This is useful,
e.g., in the case of extended source analysis or close to spectral background
- badpixfind: The task now permits bad pixel searching on calibrated
multi-chip eventsets(e.g. final pipeline product). Previous versions only
operated on raw event lists.
an alternative new method for signal offset subtraction is offered in
rgsenergy. Files containing averaged offset signals for each three
consecutive revolutions are new constituents of the Observation Data File
They make possible the subtraction of the offset signal on a pixel-by-pixel
basis, which should be more accurate than subtracting a single value per CCD
readout node (this continues to be the default method in rgsenergy).
For older ODFs those new constituents can be retrieved from the repository
(under ftp://xmm.vilspa.esa.es/pub/RGS/OFFSET/). A README file located in
directory gives further details.
- grism data processing is now enabled.
This new version of SAS contains by the first time utilities to deal with
data obtained with the OM grisms. A new metatask, omgchain, can be
used to extract and automatically calibrate spectra produced by OM grisms.
These OM data are taken in Image Mode. Hence omgchain uses already existing
tasks, such as omprep and ommodmap, to handle housekeeping information and to
perform some corrections as the "modulo 8" noise reduction. Also omdetect is
used to find the spectra, zero and first orders, producing a source list.
Some new tasks are grism specific. omgprep, is used to correct for geometric
distortion of the detector and to rotate the image so as to have the
dispersion direction aligned with the image Y axis. omgprep performs the
spectral extraction and the wavelength and flux calibration. Finally, the
extracted spectra are plotted using omgplot.
A new, interactive task, omgsource, allows the user to select with the
cursor the spectrum to be extracted.
- photometric calibration.
OM photometry has been completed in this SAS version with a new PSF for the
UVW1, UVM2 and UVW2 filters. The form of the PSF is taken into account when
measuring the count rates of the detected sources.
- OM source positions are corrected for a 0.5 pixel position error in both
and Image Mode exposures.
- a new task parameter handling system, which is capable of understanding
complex expressions for allowable values, in addition to setting default
values as in former SAS versions. Furthermore, parameters can have
child-parameters, depending on its value, and this makes possible the
setting of controlling parameters, if a child parameter is activated on the
command line (e.g. evselect --xcolumn=RAWX implies withimageset=yes, which
does not need anymore to be explicitly specified). This presents large
advantages at the time of writing scripts, which can be much more compact
in the past. However, "old" scripts have to be revised to avoid setting
implicitly undesired parameters. This will be explained in more detail in a,
soon to be available, "SAS watchout" page.
Please notice that a number of new calibration constituent files (CCF) have
been released together with the SAS 6.0.0, which are necessary for running
some of the tasks. You can follow the CCF download instructions at
A number of SAS tasks are now fully integrated in the new release of the
XMM-Newton Science Archive (XSA; http://xmm.vilspa.esa.es/xsa). EPIC, RGS
and OM data reduction meta-tasks, EPIC event list filtering and interactive
generation of EPIC scientific products (spectra, response matrices, light
curves) can be run from the XSA user interface version v2.5
of these functionalities to the new SAS version (6.0) is ongoing.
4th VILSPA SAS Workshop
There are still a few places available to attend the 4th VILSPA SAS Workshop,
which will be held from June 8 to 11, 2004.
The SAS Workshops aim at providing potential XMM-Newton users, having no or
little experience of XMM-Newton data analysis, with an introduction to the
procedures and techniques to successfully reduce and analyze XMM-Newton data.
No specific knowledge of X-ray data analysis is required to attend the
workshop. Astronomers with experience in wavelengths other than X-rays are
warmly encouraged to apply.
Everybody interested to attend should fill-in and submit the registration
available at the URL:
The same web page provides detailed information on the workshop program, and
accommodation facilities for workshop participants.
The deadline for registration is April 30, 2004.
Conference Announcement: Exploring the X-ray Universe
A 3 day meeting will be held from 22-24th June 2004 at the Mullard Space
Science Laboratory, Holmbury St Mary, UK. The meeting will encompass various
aspects of X-ray observations in the universe - from the Sun to stars to
supernova remnants to active galactic nuclei. The meeting is held in honour
of Prof. J. Len Culhane's career to date. The details of the scientific
programme and the deadlines are on the following website
XMM-NEWS mailing list
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