K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G.
Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi
(INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B.
Sbarufatti (PSU) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT has performed follow-up observations of the Fermi/GBM and
Swift/BAT-GUANO detected burst GRB 201008A (DeLaunay et al. GCN Circ.
28583), collecting 4.5 ks of Photon Counting (PC) mode data between
T0+46.9 ks and T0+60.1 ks.
Two uncatalogued X-ray sources have been detected consistent with being
within 296 arcsec of the BAT/GUANO position, however none of them is
above the RASS limit or shows definitive signs of fading. Therefore, at
the present time we cannot identify which, if any, is the afterglow.
Details of these sources are given below:
RA (J2000.0): 161.7543 = 10:47:1.02
Dec (J2000.0): +46.1475 = +46:08:51.1
Error: 5.1 arcsec (radius, 90% conf.)
Count-rate: (1.79 [+1.09, -0.80])e-3 ct s^-1
Distance: 169 arcsec from BAT position.
NB, this position is consistent with SDSS J104701.20+460848.8,
a likely quasar in the SDSS Quasar Catalogue. If this association
and ID is accurate, this source is unlikely to be related to the GRB.
RA (J2000.0): 161.8588 = 10:47:26.10
Dec (J2000.0): +46.1019 = +46:06:06.9
Error: 4.8 arcsec (radius, 90% conf.)
Count-rate: (4.1 [+1.3, -1.1])e-3 ct s^-1
Distance: 286 arcsec from BAT position.
Flux: (1.68 [+0.52, -0.44])e-10 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Two uncatalogued sources were also detected too far from the GRB
position to be likely afterglow candidates.
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
This circular is an official product of the Swift-XRT team.