pca_bs HEADAS help file

NAME

pca_bs -- rudimentary RXTE PCA background subtraction using scalings

USAGE

         pca_bs -[bcdhilptx]

DESCRIPTION

The pca_bs script provides rudimentary RXTE PCA background subtraction by using PCA anode layer information. This subtraction is not considered as sophisticated as pcabackest for most situations.

The user provides

         a list of input files in the fits_files.txt format
         a root for the output filenames
         the binsize in seconds for the light curves
         an (optional) filename for an ASCII file containing
              time information (e.g. a TIMETRANS output file)

and the PCA_BS will construct light curves in each of 6 energy bands for Layer 1 and for Layer 2+3. It will then subtract the Layer 2+3 'background' from the Layer 1 'source' with the appropriate scalings, as defined by the Arnold Rots/Keith Jahoda recipe for PCA lightcurve background subtraction for faint sources. (This memo is required reading before running this task.)

The channels are hardwired in, but can be changed by editing the perl script itself.

The p(i) and q(i) constants from the memo are set up on the first page of the code, just under the startup banner, and can be changed there if updated numbers are given. The script currently chooses the proper p and q coefficients based on the observation date.

The X(i) constants from the memo can be subtracted out too. The script will, by default, choose the cosmic x-ray background rates based on observation date, but the user can specify either "NONE" to do no CXB subtraction or else the name of a file containing an alternate set of CXB rates.

PARAMETERS (actually SWITCHES/FLAGS) (grouped by function):

-i {file}: provide name of ASCII file containing list of XTE/SA files (assumed default: 'fits_files.txt').
-p {file}: provide root for product files - i.e., 'pca_bs -p one' will create files oneA_B.lc, where A = channel band, and B = 1 or 23, depending on level, and background-subtracted files oneA.lc (assumed default: 'band').
-t {file}: provide ASCII filename containing time filter info in the usual format, or INDEF or '-' for none.
-x {file}: provide ASCII filename containing cosmic x-ray background info in the usual format; INDEF or '-' for default values; NONE for no cosmic x-ray background correction.
-b {number} - provide requested binning for light curve file - i.e.: 'pca_bs -b 1.0' will create 1-second bins. (assumed default: 32 seconds).
-c: prompt for names of layer1 and layer2+3 column files
-d: Take default values for all parameters not set on the command line.
-l: Logfile switch. Currently, logging is the default (in a file pca_bs.log), and -l will disable this logging.
-h: Print this help information.

EXAMPLES

pca_bs
pca_bs -i infiles -p out -t times.tfl -b 256.0
pca_bs -b 32.0 -p torres -d

NOTES

PCA_BS is intended as a 'fast' tool to minimize the amount of FTOOLing around for the user with straightforward data analysis requirements. It is not intended to replace or reproduce the full functionality available from the individual FTOOLS.

BUGS

Please report problems to xtehelp@athena.gsfc.nasa.gov.