Converting light curves to OGIP FITS format

It is expected that most users will wish to analyse their data using the xronos timing analysis package (Stella & Angelini 1993), which is part of the XANADU suite of software. The Ginga time series files have to be converted into files following the OGIP FITS conventions (Angelini, Pence & Tennant 1994) using the program ginga_lc. The following is an example of its use:

qcl>ginga_lc
 
** GINGA_LC Version 1.4 Mon Aug 18 14:53:43 1997 **
 
GNG_NCUBE Number of data files = 0 =1
GNG_DATIN001 Data filenames =mkn335_91a.time
GNG_IDMX Input response matrix file = $XADMX/low.idmx =
Data file has  2 IDENT channels
GNG_IDENT IDENT channel to extract = 0 =1
Opening file: mkn335_91a.lc
qcl>

A response matrix is required because the OGIP FITS conventions specify that the energy interval, over which intensity values are accumulated, should be present in the output FITS file. This information is present only in the response matrix. The response matrix $XADMX/low.idmx is appropriate for observations taken when the high voltage was operated at ~1830 V. For observations taken during periods when the high voltage was reduced to ~1745 V, the user must specify the $XADMX/special.idmx response matrix. The output FITS files are given the suffix ".lc". If the input file has a spectral axis, then the program will prompt the user for the spectral channel to extract. Unlike the program ginga2xsp (see section 7.3 ), ginga_lc has no capability for extracting multiple light curves.