TITLE:   GCN CIRCULAR
NUMBER:  22235
SUBJECT: GRB 171210A: Swift-XRT and UVOT observations
DATE:    17/12/11 13:22:48 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAB), A. Tohuvavohu (PSU), S. J.
LaPorte (PSU), P.A. Evans (U. Leicester), P. D'Avanzo (INAF-OAB) and 
N. P. M. Kuin (UCL-MSSL) report on behalf of the Swift team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 171210A (Bissaldi et al. GCN Circ. 22228),

collecting 5.0 ks of Photon Counting (PC) mode data between T0+34.7 ks
and T0+46.3 ks. 

Five uncatalogued X-ray sources have been detected, 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:

Source 1:
  RA (J2000.0):  335.26545  =  22:21:3.71
  Dec (J2000.0): +24.47028  =  +24:28:13.0
  Error: 2.9 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (7.5 [+1.5, -1.4])e-3 ct s^-1   
  Distance: 182 arcsec from Fermi/LAT position.
  Flux: (2.20 [+0.45, -0.41])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

This source lies 5.0" away from SDSS J222103.88+242817.4, which is
catalogued as a candidate quasar (Brescia et al., 2015, MNRAS, 450,
3893).

Source 2:
  RA (J2000.0):  335.2458  =  22:20:58.99
  Dec (J2000.0): +24.6016  =  +24:36:05.7
  Error: 5.7 arcsec (radius, 90% conf.)
  Count-rate: (2.23 [+0.98, -0.76])e-3 ct s^-1	 
  Distance: 618 arcsec from Fermi/LAT position.
  Flux: (2.44 [+1.07, -0.83])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

This source lies 6.4" away from SDSS J222058.65+243610.1, which is
catalogued as a candidate quasar (Brescia et al., 2015, MNRAS, 450,
3893).

Source 3:
  RA (J2000.0):  335.4135  =  22:21:39.23
  Dec (J2000.0): +24.5534  =  +24:33:12.4
  Error: 7.0 arcsec (radius, 90% conf.)
  Count-rate: (3.01 [+1.11, -0.90])e-3 ct s^-1	 
  Distance: 530 arcsec from Fermi/LAT position.
  Flux: (8.4 [+3.1, -2.5])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
This source lies 2.6" away from SDSS J222139.19+243314.9, which is
catalogued as a candidate quasar (Brescia et al., 2015, MNRAS, 450,
3893).

Source 4:
  RA (J2000.0):  335.42877  =  22:21:42.90
  Dec (J2000.0): +24.30996  =  +24:18:35.9
  Error: 2.4 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0137 +/- 0.0022 ct s^-1   
  Distance: 608 arcsec from Fermi/LAT position.
  Flux: (4.08 [+0.66, -0.64])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

This source lies 1.3" away from SDSS J222142.87+241837.0, which is
catalogued as a candidate quasar (Brescia et al., 2015, MNRAS, 450,
3893).

Source 5:
  RA (J2000.0):  335.37378  =  22:21:29.71
  Dec (J2000.0): +24.49242  =  +24:29:32.7
  Error: 2.3 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (8.8 [+1.9, -1.8])e-3 ct s^-1   
  Distance: 281 arcsec from Fermi/LAT position.
  Flux: (3.00 [+0.65, -0.63])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

This source lies 1.7" away from SDSS J222129.58+242933.1, which is
catalogued as a candidate quasar (Brescia et al., 2015, MNRAS, 450,
3893).


The results of the XRT-team automatic analysis of the XRT observations,

including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020785.


Simultaneous with the XRT, the UVOT observed the target region of GRB
171210A. Due to the smaller field of view, two of the candidate sources
(#2 and #4) are not on the UVOT image. The other candidate regions have
been examined but do not show any new sources. A further comparison of
the whole UVOT observation to the DSS survey shows no new sources. 

We acknowledge the use of the VizieR catalogue access tool, CDS,
Strasbourg, France.


This circular is an official product of the Swift team.