O.M. Littlejohns, P.A. Evans, K.L. Page (U. Leicester), A. Melandri, P.
D'Avanzo (INAF-OAB) and J.Racusin (GSFC) reports on behalf of the
We have analysed 10 ks of XRT data for GRB 120624B (Barthelmy et al.
GCN Circ. 13381), from 218.7 ks to 260.9 ks after the BAT trigger. The
data are entirely in Photon Counting (PC) mode. Inside the BAT refined
error circle (Sakamoto et al. GCN Circ. 13384) we find an uncatalogued
X-ray source (S1) at RA, Dec = 170.8845, +8.9283 which is equivalent
RA (J2000): 11 23 32.28
Dec(J2000): +08 55 42.0
with an uncertainty of 4.3 arcsec (radius, 90% confidence). This source
lies 40 arcsec from the NIR object reported by D'Avanzo et al. (GCN
Circ. 13391). We cannot determine at the present time whether the
source is fading, the count-rate is approximately 2e-3 ct/sec in XRT.
There is a second source (S2) at RA, Dec = 170.8670, +8.9319 which is
RA (J2000): 11 23 28.07
Dec(J2000): +08 55 54.8
with an uncertainty of 4.2 arcsec (radius, 90% confidence). This source
is 70 arcsec away from the BAT refined position, just outside the error
circle. This source is 35 arcsec from the NIR counterpart. This source
has a count-rate of approximately 1e-3 ct/sec, and again we cannot
measure variability at this time.
An image of the XRT field, with the two XRT sources, BAT error circle
and NIR source marked, is available at
Further observations are planned.
This circular is an official product of the Swift-XRT team.