Subject: JEM-X Monday Meeting 2005-11-21

2005-11-21

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

Status for JEMX instruments (SB): There is some hotspot activity - up to
      100 cts/s in very limited timeperiods. No new dead anodes.

Gain correction and smoothing (NL): Discussion of Stephane's suggestion.
      CAO to make a proposal based on this as a reply. Still important to
      see that the Xe line from the background is found around 29.6 keV.

Gain archive (CAO): Xe and Mo line positions are quite stable with new IMOD
      epochs. In a case of strong background (revolution 276) the overall gain 
is
      suppressed whereas the gain under the calibration sources is not affected
      so much since they are already heavily exposed resulting in a Xe line
      appearing around 28 keV.

Alignment (CBJ): Source positions for 20 reference sources obtained from
      SIMBAD with four decimal places makes it possible to have almost
      all these positions acurate under 3 arcsec. For this result it is 
necessary
      to use the mask temperature as a fitting parameter.

Spectral extraction status (NL): The subroutines from j_ima_iros will be
      used as building blocks. The new extraction component will be a PIF
      generating tool, basically. The name could be: j_src_pif.
      At low energy the distribution in the detector depends on the
      photon energy as well as on the local gain.
      
INTEGRAL operations w.r.t. 5x5 dither (NL): Stepsize 2.17 deg in stead of
      2.0 deg is preferred by IBIS people, except for hex-dither which is
      to be used if JEM-X results are important. This strategy is
      endorsed by the JEM-X team, but we would still like to see a proof that
      2.17 deg separation gives improved imaging etc.

New meeting as a follow-up on Wednesday 2005-11-23.

/NJW

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Niels J. Westergaard
Danish National Space Center
Juliane Maries Vej 30, DK 2100 Copenhagen O
Phone: +45 35325705; FAX:  +45 35362475