GCN Circular 4202
Subject
GRB 051105a: MDM Observations
Event
Date
2005-11-06T05:04:24Z (20 years ago)
From
Jules Halpern at Columbia U. <jules@astro.columbia.edu>
J. P. Halpern, S. Tonnesen, S. Tuttle (Columbia U.), and N. Mirabal
(U. Michigan) report on behalf of the MDM Observatory GRB follow-up team:
"We observed the location of Swift GRB 051105a (Mineo et al., GCN #4188)
using the MDM 2.4m telescope, with a 4.6x4.6 arcminute field centered
on the improved BAT position (Barbier et al., GCN #4194). A total of
2 and 30 minutes exposure were obtained in the Gunn g and r filters,
respectively. The mean epoch of the observations was Nov. 6 02:39 UT,
or 20 hours after the burst. The following R magnitudes of objects
mentioned in previous GCN circulars were measured, referenced to the
comparison star magnitude R=17.0 used by Piranomonte et al. (GCN #4201):
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R.A. (J2000) Decl. (J2000) R(mag) ID GCN ref
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17 41 10.00 +34 55 45.2 21.15 +/- 0.03 inside XRT S1 4195,4196,4201
17 41 10.28 +34 55 41.1 22.50 +/- 0.12 outside XRT S1 4196,4201
17 41 03.28 +34 59 03.6 23.24 +/- 0.22 radio 4199
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Positional uncertainties are 0.3" in the USNO B1.0 reference system, except
for the faint object that is, nevertheless, consistent in position with the
radio source of Frail & Cameron (GCN #4199). The bright object in the error
circle of XRT S1 is clearly blue in g-r, as well as on the Palomar Sky Survey
plates, and might therefore be an X-ray detected QSO. Our magnitude of it
is consistent with that measured by Piranomonte et al. (GCN #4201) 7 hours
earlier."