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ROSAT Guest Observer Facility

ROSAT FTOOLS, by Jane Turner

A number of new ftools have been released which are useful for ROSAT analysis.

New in the ROSAT package:

pcsasscor - Performs spatial gain recorrection on PSPC events file

This tool was previously known as pcpicor, and corrects the PI column of a ROSAT events file for a bug in the spatial gain correction applied by all versions of SASS used to date.

pctcor - Applies a time-dependent correction to PI data

pctcor corrects for uncalibrated spatial gain variations across the face of the detector. It uses gain maps produced from the on-board Al K alpha calibration data. The calibration data were binned in roughly 100 day intervals and then fit for the gain on a 2 arc minute grid.

pcecor - Applies an energy dependent term to time correction of the PI data

pcecor uses the results of Prieto, Hasinger, and Snowden (1996, A&A, in press) and calibration data from the PANTER facility in Neuried to correct for the variation in the linearity of the PSPC response with absolute gain and time. The Panter data were collected several years after the launch of ROSAT using the engineering model PSPC. It was observed that the effective gain in the 0.25 - 1.0 keV energy range was lower than expected after normalizing to the 1.5 keV monitor line, and this effect became worse with lower absolute gain. For example, a 0.75 keV X-ray might be detected as a 0.72 keV X-ray when the PSPC was operating at low gain. Data from higher energy calibration lines were collected at the same time, which allowed a check of response linearity over an extended energy range.

pcpicor - script which spawns PI correction tasks pcsasscor, pcecor, pctcor

The ftool previously released under the pcpicor name performed the correction which is now know as pcsasscor. This new script version of pcpicor spawns all the PI correction tasks, pcsasscor, pcecor and pctcor.

*Warning* - spectra extracted after correction for all time dependent effects should not be fit using the pspcb/c_gain1/2 matrices. A new matrix will shortly be released for use with corrected data (expected by May 1996). Please contact the ROSAT GOF for updates.

Useful new general tasks:

extrpsf - Extracts a radial profile directly from an events file

This allows an extraction of a FITS format radial profile directly from the ROSAT events file in circular annuli. User inputs include the desired energy range, the specification of the centroid and extent of the radial profile and some options related to error and background handling. Later releases of this task will allow region masks to be applied to screen-out regions which should be excluded from the radial profile.

The output from this task can be compared to the theoretical profile using the rbnrpsf, pcrpsf, rpsfqdp, rpsf2eef tasks (or the calcrpsf script which spawns these). Please read the online help file for more details and current limitations of this first version of the task.

rpsf2eef  	- converts radial point spread format to encircled energy function
caldbinfo 	- Gives info on caldb setup
addspec  	- adds pha spectra

The most recent release versions of FTOOLS and XSELECT are available via the anonymous FTP site in a subdirectory of the directory /software/ftools/release, and is available on the following platforms

unix     ALPHA/OSF, DEC/ULTRIX, SUN/SunOS, Sun/Solaris, MODCOMP/REALIX,
vms      ALPHA/VMS, VAX/VMS
You will need to get the files:

ftools.vx.x.tar.Z	-  Source Code Distribution for all platforms
refdata.vx.x.tar.Z 	-  Minimal subset of Calibration Database
where vx.x is a version number.

The Compressed Postscript Documentation is available at /software/ftools/release/doc and includes

develop.ps.Z 		-  Developer's Guide
install.ps.Z 		-  Installation Guide
users.ps.Z 		-  General FTOOLS User's Guide
techref.ps.Z		-  Complete User's Guide and help pages
Xselect_vx.x.ps.Z	-  

A ROSAT User's Guide to data analysis using XSELECT and FTOOLS is available in postscript and LaTeX form from the legacy.gsfc.nasa.gov anonymous FTP area under /rosat/doc/xselect_guide and via the WWW at http://heasarc.gsfc.nasa.gov/docs/rosat/ros_xselect_guide/xselect_ftools.html The Users Guide will be updated shortly, to reflect these additions and some other minor changes. For more details on the new tasks please see the online help files, or contact the ROSAT GOF via the Feedback form.

The ROSAT FTOOLS page on the World Wide Web describes the latest FTOOLS and perl scripts, the URL is http://heasarc.gsfc.nasa.gov/docs/software/ftools/rosat.html.


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Curator: Michael Arida (SP Sys); arida@milkyway.gsfc.nasa.gov
HEASARC Guest Observer Facility


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This file was last modified on Friday, 19-Jul-2002 11:52:01 EDT

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