HXD GSO Background

Documents on the current GSO background model

We have summarized the method and reproducibility of the GSO background modeling in the following two documents:

Suzaku memo 2007-02
"Modeling of the HXD-GSO Background"

Suzaku memo 2006-43
"Reproducibility of the HXD-GSO Non X-ray Background"

The release of HXD-GSO background files for version 1.2 process

The GSO background files for ver1.2 process are prepared by the HXD team. The detailed description on the production process of background files and studies of the background accuracy is now being prepared by the HXD team, and will be circulated until the end of December or so.

GSO background files are available from this page.

General Notes for GSO-BGD:

1. The event rate of BGD event file is not 10 times as that of PIN-BGD, and thus you should not correct the exposure.
2. You should reprocess the second FITS files of your own data before subtracting the GSO background. See the page of "seven steps for HXD analysis" or the ABC guide.
   http://www.astro.isas.jaxa.jp/suzaku/analysis/7step_HXD.txt
3. You should perform the binning of both observation and background spectra as followings.
4. You should correct the dead time of the GSO-BGD spectral file, as well as the observation spectral file.
5. The BGD event file does not include the CXB. However, the CXB is less than 0.1% of the total background rate, and thus it is negligible.
6. The accuracy of model is expected to reach as good as 3 % of the averaged background. Observers are strongly recommended to verify the reliability of background, by comparing the model spectrum and light curve with the "earth occultated data" which can be obtained on the condition of "ELV<-5". Due to the change of intruementa set-up, the GSO BGD rate is sometimes different from the model significantly in the period of 2005/3/19 -- 2006/5/29. Please check the HXD operation log.
   http://www.astro.isas.jaxa.jp/suzaku/log/hxd/
   Also, in this period, the data transfer rate in the instrument sometimes saturated. Please elliminate this period by the new version of the tools "hxdgtigen".

	binning of both observation and background spectra by "grppha": 

	group 0 24 25 25 26 2 27 28 2 29 31 3 32 35 4 36 38 3 
	group 39 42 4 43 46 4 47 51 5 52 56 5 57 62 6 
	group 63 68 6 69 75 7 76 83 8 84 91 8 92 100 9 
	group 101 110 10 111 121 11 122 134 13 135 147 13 148 162 15 
	group 163 178 16 179 196 18 197 216 20 217 238 22 239 262 24 
	group 263 288 26 289 317 29 318 349 32 350 384 35 385 422 38 
	group 423 465 43 466 511 46