Subject: DSRI JEMX group meeting 040126, minutes

Present: SB, JC, CAO, NL, CBJ, NJW

1) Status for JEM-X: (CBJ) looks OK. (SB) a 15% decrease in (background)
   countrate - both hardware triggers and accepted events - was experienced
   2004-01-22. The IREM electron counts and results from "GOES" satellite
   show a simultaneous pronounced decrease of electron flux.
   
   Due to the change of gain behaviour following switch-on after perigee
   compared to switch-on after shorter break we would like to have two
   formally different switch-on procedures.
2) Change request and ISWT news (NL)
   The changeover from JEM X-2 to JEM X-1 after Crab calibration was
   approved. JEM X-2 will be revived for 10-20 hours after 14 days and
   again after 2 months to follow its condition. (For these periods we
   might want extra TM packets).
   There was a discussion on dither patterns. The current mode moves the
   primary source along the ghost pattern directions of IBIS and it
   repeats the pointings when several cycles are executed which is not
   optimal for SPI.
   ISGRI response below 20 keV is not understood well.
   ISWT is to be transformed into an 'INTEGRAL User Group' with larger
   representation of the actual users of INTEGRAL.
   AO2 will be extended to 14 months in stead of 12 months to accomodate
   sufficient Russian observation time.
3) New source. (JC) no real news. ISGRI detection very uncertain. ATEL
   must go out soon.
4) Source survey (NJW) no news.
5) Light curves (NL, CBJ, NJW) The ISSW light curves (j_src_extract_lc)
   show a sinusoidal pattern for GRS1915+105 in Rev 59 correlated with
   the azimuth of the source in the instrument FOV. The CBJ lightcurves
   also show this dependende but less pronounced. A misalignment error
   or bad source positioning would produce such variations.
   NL is working on including Restricted Imaging data in the light curve
   extraction.
6) JEMIROS (JC) No news. NL will invite Paul Connell to stay at DSRI a
   couple of days to work together on this.
7) RW mosaics. (NL) Rather nice mosaic images have now been made by RW.
   There are still ring shapes around strong sources but the noise has
   been reduced considerably (around GRS1915 there is also a quadratic
   pattern in the background).
   
/NJ

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Niels J. Westergaard
Danish Space Research Institute
Juliane Maries Vej 30, DK 2100 Copenhagen O
Phone: +45 35 32 57 05; FAX:  +45 35 36 24 75