[vsnet-grb-info 4848] INTEGRAL burst GRB070615: X-ray continued observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6580
SUBJECT: INTEGRAL burst GRB070615: X-ray continued observations
DATE:    07/06/26 15:01:42 GMT
FROM:    Olivier Godet at U.of Leicester  <og19 at star.le.ac.uk>

O. Godet, N. Lyons, K.L. Page, A.P. Beardmore (U. Leicester) report on 
behalf the Swift-XRT team:

In Godet et al. (GCN Circ. 6544), we reported the detection of a faint 
and uncatalogued X-ray source after analysing 3ks of Swift PC data taken 
10.7h after the IBAS trigger (Mereghetti et al., GCN Circ. 6537). We 
estimated the source count rate to be between 5.5e-4 c/s and 3.6e-3 c/s 
at a 95% confidence level using the Bayesian method. However, it was 
impossible to say whether or not the source was fading due to the limited 
statistics.

We analysed 8.5ks of additional PC data taken 6.9 days after the IBAS
trigger and no counts were found inside the 7.5 arcsec radius error
circle. In this region, only 0.1 background counts would be expected. 
Using the Bayesian method, we estimated the upper limit on the count 
rate to be around 3.5e-4 c/s at a 95% confidence level.
So, the weak X-ray source may be fading.

This is an official product of the Swift XRT team.