Subject: Crab light curve (IROS)

Hello Stephane,

I have plotted your Crab flux results using your src_1.fits file
split up into 5 periods: Revol 39-45,102,170,239, and 300 in the
four energy bands - one plot file per energy band.
The results have been plotted both as a function of time and
as a function of off-angle.

Remarks
1) There was a drastic change of rejection criteria in revol. 44
    which opened in particular the low energy end of the spectrum
    This explains the about a factor of two increase of 3-6 keV flux
    between revol 44 (IJD ~1150 d) and revol 102 (IJD ~1323).
    Similarly the 6-10 keV band is also affected (by ~20%).
2) There is no clear sign of a flux increase with time for pointings
    with small off-angle. There is a sign of higher flux estimate
    with larger off-angle and this trend should be corrected somehow.
    The errors look under-estimated for these results.
3) There are some problems with some on-axis flux determinations
    that I will investigate
    
Unfortunate I missed you explanation of how you did the analysis in
smaller time bins than science windows. Most of the near-zero results
could arise from some improper handling when the time interval has
been cut.

Could you explain to me how it was done ? Then I'll see, if there is
something we can do for j_ima_iros.

Regards

Niels Jűrgen


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

X-Original-To: oxborrow@dsri.dk
Delivered-To: oxborrow@dsri.dk
Date: Sun, 29 May 2005 17:40:15 +0200 (MEST)
From: Niels Joergen Westergaard <njw@spacecenter.dk>
To: Active SDAST -- Carl Budtz-Jorgensen <carl@spacecenter.dk>, Carol Anne Oxborrow <oxborrow@dsri.dk>, JĂ©rĂŽme Chenevez <jerome@dsri.dk>, "Niels J. Westergaard" <njw@dsri.dk>, Niels Lund <nl@spacecenter.dk>, Paul Connell <paul.connell@uv.es>, Peter Kretschmar <peter.kretschmar@obs.unige.ch>, Sami Maisala <smaisala@astro.helsinki.fi>, Silvia MartĂ­nez NĂșñez <silvia.martinez@uv.es>, Soren Brandt <sb@dsri.dk>, Stefan Larsson <stefan@astro.su.se>, Stephane Paltani <Stephane.Paltani@obs.unige.ch>
Subject: OBS new flux figures
MIME-Version: 1.0

Hello all,

I had made a serious mistake in the previous set of figures of the IROS
extracted fluxes: I had silently assumed that only Crab fluxes were given
in Stephane's file. That is not true - I think that all found sources are
given, hence the large number of data points with very low fluxes.

In the attached set of figures the selection NAME=="Crab" has been done
and the figures look much nicer, but the conclusions are unaltered given
that the low flux points were discarded from influence.

Sorry for the mess but at least the change is to the better.

Regards

Niels Joergen

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