Spectral Analysis of the WAM data

First you need to produce spectral FITS file ($*$pha) using hxdmkbstspec for the BST data or/and hxdmkwamspec for the TRN data. You should always correct for the detector deadtime using the dt_cor option (dt_cor=yes), and give the start time (time_min) and end time (time_max) for spectral integration in ASTETIME.

hxdmkbstspec input_name=ae903005010hxd_1_bst01_uf.evt.gz \
          outroot=ae903005010hxd_1_bst01 tpu_board=-1 th_mode=0 \
          time_min=276787164 time_max=276869264 dt_cor=yes

hxdmkwamspec input_name=ae903005010hxd_1_wam_uf.evt.gz \ 
        outroot=ae903005010hxd_1 tpu_board=-1\
        time_min=276787164 time_max=276869264 dt_cor=yes

After that, you can enjoy spectral fitting in XSPEC. The background spectra can be derived by 1)integrating a few 10-100 seconds before and after the bursts if the background level is almost constant or 2) estimating the background contribution with modeling of the background (the tools might be available in a future).

The response generator, wamrspgen, will not be made publicly available due to its complex structure. The WAM team will make the response matrices for certain GRBs publicly available at the web site. If you want response matrices for other GRBs, please contact WAM team via their e-mail adress.

XSPEC12>data 1:1 wam0_grb.pha (GRB spectrum)
XSPEC12>backgrnd 1 wam0_bg.pha  (Background spectrum)
XSPEC12>response 1 wam0_grb.rsp (Response file)

Many GRBs are detected by more than two WAM detectors. To constrain the spectral parameters more tightly, you can perform joint fitting between two WAM detectors.

XSPEC12>data 2:2 wam1_grb.pha 
XSPEC12>backgrnd 2 wam1_bg.pha
XSPEC12>response 2 wam1_grb.rsp

The current response have systematic uncertainties in low energies (below $\sim$150 keV). So you had better ignore 0$-$3 channels in spectral fitting as follows.

XSPEC12> ignore **-4

High energy channels which you should choose depend on photon statistics. Note that there are typical 20% calibration uncertainties in the absolute flux. Please see the calibration status (Sakamoto et al. 2011 and Yamaoka et al. 2009)