The SWIFT BAT Software Guide Version 6.3 30 ... - HEASARC - Nasa

5.7. SPECTRUM AND RESPONSE MATRIX 43
Figure 5.4: Schematic diagram of the operations that must be performed on a BAT spectrum after
it has been created, in order to be suitable for spectral fitting in XSPEC.
5.7 Spectrum and Response Matrix
This section describes how to make a spectrum from BAT event data using the task ‘batbinevt’.
After creating a raw spectrum, certain corrections must be applied, and then a response matrix
can be created.
Figure 5.2 shows that spectra are created with the ‘batbinevt’ task. Figure 5.4 shows the steps
that must be taken after the spectrum has been created.
5.7.1 Introduction
Making a spectrum involves selecting the time of interest, and the desired energy binning.
Let’s assume we are interested in the burst GRB 050713A, in particular a flare from time
142921843 (MET) to 142921868 (MET).
5.7.2 Prerequisites
• BAT event data (in obsid/bat/event/swNNNNNNNNNNNbevshsp uf.evt.gz);
• BAT quality map (in obsid/bat/hk/swNNNNNNNNNNNbcbdq.hk.gz).
• BAT event auxiliary raytracing file (in obsid/bat/event/swNNNNNNNNNNNbevtr.fits.gz);
We will use the original event list of GRB 050713A as an example (obsid 00145675 000). The
event data should have been ray-traced by the SDC using the position of the GRB. Energy calibrations
should also have been applied. See the Mask-Weighting and Energy Correction threads
for more information.
If the auxilliary raytracing file is not available (it was not archived by the SDC until late 2005),
then it must be recreated using the Mask-Weighting thread.