[vsnet-grb-info 5999] Possible GRB 080315: XRT non-detection of afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7638
SUBJECT: Possible GRB 080315: XRT non-detection of afterglow
DATE:    08/04/22 13:28:33 GMT
FROM:    Kim Page at U.of Leicester  <kpa at star.le.ac.uk>

K.L. Page (U. Leicester) and N. Gehrels (NASA/GSFC) report on behalf of 
the Swift-XRT team:

Swift-XRT performed follow-up observations of the possible GRB 080315 (BAT 
trigger number 306323) about a month after the trigger, in order to 
determine whether or not the possible X-ray afterglow mentioned in GCN 
Circ. 7420 had faded. We find that this source is at a count rate 
consistent with that of our original observation, so conclude that it is 
not the afterglow. Thus, no afterglow was detected for this trigger.

Excluding this constant X-ray source, the 3-sigma upper limit within the 
BAT error circle from the observation directly following the trigger (25 
ks on 2008-03-15) was 5.9 x 10^-4 count s^-1; the late-time data (30 ks 
between 2008-04-16 and 2008-04-21) provide a limit of 5.2 x 10^-4 count 
s^-1. 

We cannot rule out that this was a real burst, but given the lack of XRT 
detection and marginal BAT detection it is not likely.