National Aeronautics and Space Administration

EXOSAT Software

Data Products: The images The FITS images may be displayed using any standard package which accepts FITS images. Examples include SAOIMAGE and fv for UNIX (see fv page), NIHImage for MacOS, IMDISP under DOS and FITSview under MS under MS Windows. XIMAGE and IDL are also useful for display and analysis of the FITS image file.

Data Products: Spectra and Lightcurves Spectra and lightcurves can be analyzed using Xspec and Xronos respectively. Xspec is a general spectral fitting programs, providing a number of already made standard models. To use XSPEC with the EXOSAT archive files, it is necessary to extract from the archive a source spectrum and a response matrix for the ME and GSPC experiment. For the TGS also the background spectra is necessary.
The EXOSAT lightcurves can be used in any of the Xronos programs, each dedicated to a specific timing task.

The LE Raw files : The average images, and lightcurves are adequate products for many type of studies. However for specific studies images (and/or lightcurves) need to be re-extracted from the LE raw data file, the events file. The basic program to use is Xselect . This extracts images, spectra and lightcurves setting basic filtering on time, phase intensity, energy and region. However before using Xselect it is recommended to use the mission-specific software in the EXOSAT package. An example illustrating the usage of Xselect and the EXOSAT-specific software in creating a lightcurve from LE event files is given here.

General FITS file manipulation : The FTOOLS packages, futils and fimage , provide a suite of programs that can be used to view and manipulate any of the EXOSAT FITS archive files. To view the FITS bintable data particularly useful are the tasks fplot (to plot the data), fdump (to dump the data file content), fstruct and flcol (to get the structure and column name of the FITS files). Basic selection and column manipulation can be done using fselect (to select rows based on the result of a boolean expression), fcalc (to calculate values for new column based on arithmetic expression) and fstatistic (to compute standard statistical value on a column). The content of an image file can be viewed using fimgdmp and fimgstat computes standard statistic on an image. Alternatively most of the operations (and more) mentioned above can be done using fv , the interactive FITS file viewer and editor.