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Creating a light-curve

BAT light-curves can be created for energy bands between 15 and 350 keV, and using different time bins, down to as short as about 4 ms.

>batbinevt detmask=grb.mask
>Input event file name: sw00377487000bevshsp_uf.evt
>Output file name:
>Make light-curve or spectrum: lc
>Histogram time bin size: 1.0
>Time binning algorithm: u
>Energy bin list: 15-25, 25-50, 50-100, 100-350

Here a 1.0 second time binning has been used, for the 4 standard energy bands. The detector mask was previously created using bathotpix. If you initially processed the BAT data using batgrbproduct as described on the index page, then the detector mask will be in the newly created auxil directory, under the name *b_qmap.fits.

The 4 light-curves will be created as different extensions in the file. They can be plotted like this:

>Name of X Axis Parameter: TIME
>Name of Y Axis Parameter:RATE(1)[ERROR], RATE(2)[ERROR], RATE(3)[ERROR], RATE(4)[ERROR]
>Lists of rows: -
>Device: /xw
>Any legal PLT command:

Note that it might be useful to plot the time axis in terms of seconds after the BAT trigger. To do this, use fcalc before fplot as follows:

Name of output FITS:
Resultant column name: TIME
Arithmetic expression: TIME-TRIGTIME

This will produce a plot of the form:

with the panels showing the 15-25, 25-50, 50-100 and 100-350 keV band from top to bottom. The units plotted are count s-1 (fully illuminated detector)-1.

To save a hardcopy postscript file (called, the command is:


If a black and white version is required, use /ps instead of /cps; for a gif, use /gif. By default, a postscript file will be saved with a white background, while a gif will have a black one, unless the command scr white is given.