The analysis of the data products and the raw data in FITS format can be performed using the XANADU and FTOOLS suite of programs.
Public domain software can be used to view the GIF files (e.g. xv on UNIX or directly the Netscape browser on any system PC and MAC).
General Fits file manipulation : The FTOOLS package, futils , provides a suite of programs that can be used to view and manipulate any of the BBXRT archive files. To view the 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). Alternatively most of the operations (and more) mention above can be done using fv , the interactive FITS file viewer and editor.
Spectra and Lightcurves :
Spectra and lightcurves can be analyzed using
Xspec is a general spectral fitting programs, providing a number of already
made standard models. To use XSPEC with the BBXRT archive files,
it is necessary to extract from the archive a source and background
spectrum and a response matrix.
Raw files :
The average spectra and lightcurves are adequate products for many
type of studies.
However for specific study (for example spectral variation with
source intensity) spectra (and/or lightcurves) need to be re-extracted
from the raw data file, the events file.
The basic program to use is
Xselect . This extracts spectra
and lightcurves setting basic filtering on time, phase intensity, energy
Name of FITS file and [ext#] cygx1i.evt
Name of output FITS file clean.evt
Selection Expression LED == 0 && GUARD == 0 && VLE == 0 && PTP == 0 && PPU == 0 && detector == 1
The output file, containing only good data, can be input in Xselect
BBXRT Analysis issues : The Legacy article on BBXRT describes a number of calibration and analysis issues related with the BBXRT data. In particular the following topics are discussed:
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Last modified: Monday, 20-Apr-2020 15:46:18 EDT