Rebinning the Response Matrix

Read this if you want to use a spectral binning different from the default one. You will also learn how to rebin the response matrix to extract images in more than 10 energy ranges.

Since OSA v11.0 the IC tree contains the full response matrices (RMFs) in 256 channels, one for each set of neighbouring spacecraft revolutions (files $REP_BASE_PROD/ic/ibis/rsp/isgr_rmf_rsp_****.fits) For an efficient interaction between the analysis scripts and the IC archive, the channel-to-energy conversion for the 256 channels is stored in the file $REP_BASE_PROD/ic/ibis/rsp/isgr_ebds_mod_0001.fits. In order to be used with standard FTOOLS, the response matrix and the channel-to-energy files has to be written as two extensions of a single fits file. The science analysis scripts automatise this step as well as the rebinning of the matrices, based on the energy binning scheme defined by the user through the parameters described in Sect. . The rebinned RMFs are finally wrote to the files $REP_BASE_PROD/isgr_rmf_ebds_xxxx_rbn.fits, and attached to the og_group.

The optimum way to rebin the matrix depends on the source and on what you are interested to study, so there is not a general best way to rebin it. Nevertheless, it is reasonable not to spend time on a fine energy binning where the source is too weak and background contaminated as well as it is better to avoid too narrow energy bins for weak sources: extracting a spectrum in wider energy bins from the very beginning is better than extracting it in too fine bins, being background contaminated, and then rebinning the spectrum afterwards.

In case you want to override the use of the archived RMF, you can provide a complete RMF file, alrady rebinned according to your needs, through the SCW2_ISPE_idx_isgrResp parameter. This will cause the analysis scripts to register this RMF file name in the header of the final spectra and will prevent the usage of the correct time-dependent matrices. You should also specify, through the parameters described in Sect. , the same energy binning to be used for your spectral extraction.

Warning: This parameter is hidden. Thus you should either provide the value of this parameter during the script launch

ibis_science_analysis SCW2_ISPE_idx_isgrResp="new-rmf.fits"

or press "hidden"-button and set this parameter on the SPE page.