[AAVSO-HEN] GRB 080723B - Swift-XRT refined analysis

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  8009
SUBJECT: GRB 080723B - Swift-XRT refined analysis 
DATE:    08/07/24 07:01:14 GMT
FROM:    Kim Page at U.of Leicester  <kpa at star.le.ac.uk>

K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:

The INTEGRAL/Super-AGILE-detected GRB 080723B has now been observed by the 
Swift-XRT for three orbits (a total of ~2.3 ks of Photon Counting mode 
data). The source reported in GCN Circ. 8008 can now be seen to be fading 
(alpha = 1.27 +/- 0.23), so is confirmed as the X-ray afterglow.

A spectrum formed from the combined data (~1.3 - 30 ks after the triggers) 
can be fitted by a power-law of Gamma = 1.87 +/- 0.14, absorbed by the 
Galactic column in this direction, of 7.42x10^21 cm^-2. The average 
observed (unabsorbed) flux over this time is 1.49 (2.57) x 10^-9 erg cm^-2 
s^-1, which provides an observed counts to flux conversion of 5.9x10^-9 
erg cm^-2 count^-1.

If the decay were to continue with alpha ~1.27, the count rate 24 hours 
after the trigger woule be 0.04 count s^-1 (corresponding to an observed 
flux of 2.4x10^-10 erg cm^-2 s^-1).

The circular is an official product of the Swift-XRT team.