A. Amaral-Rogers & P.A. Evans (U. Leicester) report on behalf of the
We have observed the area around the Fermi-LAT GRB 141207A (Arimoto et
al., GCN Circ. 17146), in 4 XRT fields starting at 07:59:28 UT, 12 hours and 48 minutes after Fermi/LAT detection. With 1.3-1.7 ks per field, we find an uncatalogued X-ray source at a position of RA,Dec=160.0639,
3.8933, which is equivalent to:
RA (J2000) = 10h 40m 15.34s
Dec (J2000) = +03d 53' 35.9"
with an uncertainty of 5.2" (radius, 90% confidence). Although this
source is uncatalogued, it is a factor of 3 below the ROSAT limit at
this location, with a 0.3-10 keV flux of 1.7e-13 erg/cm^2/s. We expect
~0.9 sources at this flux to be serendipitously present in our XRT
observations, therefore we caution that this may not be the afterglow.
We cannot currently tell whether the source is fading, but follow-up
observations are planned.
There is a second uncatalogued X-ray source present in the data, at
RA,Dec=159.8172, 4.0930 with an uncertainty of 6.5"; however this source
is coincident with the object [VV2006] J103916.6+040536 which SIMBAD
classifies as a quasar, thus it is unlikely to be the GRB afterglow.
This circular is an official product of the Swift-XRT team.