Subject: Re: Sco X-1 with Jem-X Dear Georg Weidenspointner, I have just completed the Xe line analysis on all the revolutions of yours that contain SCO X-1 data, just to be sure that the energy determination has worked correctly. You can see the results on http://spacecenter.dk/~oxborrow/sdast/GAINresults.html This archive of the JEM-X gain history contains everything you need to make a well-informed judgement about the quality of your data. The good news is that despite problems with the weakness of one of the calibration sources compared to the strength of SCO X-1, very good energy determination can be done is you use the IC Gain History tables delivered to ISDC to do your analysis. If you have the latest IC package downloaded, the OSA script should find these tables automatically. See the notes for revolution 410 for a complete description of this problem and how it has been solved. See the Cd calibration figures for revolution 419 to see just how badly this problem can affect gain calibration, and how much better things are using an IC table. If you are uncertain about the Xe line position for a given Science Window, you can always take a look at the whole detector spectrum for the science window produced by the OSA pipeline in the BIN_S processing level. If you simply bin the PI data, the peak of the Xe line should be in bin 209 (first bin is number 0, see JEM-X Analysis User Manual for details). In the worst case, a science window may have an energy determination that is 3-4% too high. Generally though, gain determination lies within and around 1% of the ideal value. Where the Xe line lies unusually high there may be a correlation with the very high countrates that are associated with the SCO X-1 source, that in some cases may be capable of suppressing slightly the instrument gain around the calibration source, hence making the rest of the detector appear to produce somewhat higher energies than in reality. The notes (dated left hand column link) with each revolution should help you determine which SCWs to use and which to reject. All times are given in IJD. Generally, you're quite safe to use all the SCWs you have, however if a line appears a couple of % higher than expected it would be best to consult the various sources of information listed above before announcing something astonishing to the world. If you have any questions about the energy determination for JEM-X please get in touch with me. Good luck with your SCO X-1 analysis, Carol Anne Oxborrow DANISH NATIONAL SPACE CENTER Dr. Carol Anne Oxborrow Email: oxborrow@spacecenter.dk Homepage: http://www.spacecenter.dk/~oxborrow Telephone (direct): +45 35 32 57 33 Main teleph.: (+45) 35 32 57 00 Fax: (+45) 35 36 24 75 Main E-mail: office@spacecenter.dk A strengthened Danish National Space Center On the 1st of January 2007 the Danish National Space Center (DNSC) merged with the Technical University of Denmark (DTU). As a result of the merger a strengthened Danish National Space Center has been established, consisting of the current DNSC and parts of the Technical University of Denmark,including sections of the Ørsted-DTU Institute and IMM, DTU. Read more about the Danish National Space Center at: www.spacecenter.dk -------------------------------------------------------------------------------- -----------------