[vsnet-grb-info 14332] GRB 131231A: MDM afterglow observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15646
SUBJECT: GRB 131231A: MDM afterglow observation
DATE:    14/01/01 08:13:16 GMT
FROM:    Jules Halpern at Columbia U.  <jules at astro.columbia.edu>

J. P. Halpern (Columbia U.) reports:

I observed the afterglow of GRB 131231A (Sonbas et al., GCN 15640;
Xu et al., GCN 15641) using the 1.3m McGraw-Hill telescope of the
MDM Observatory on 2014 January 1, from 01:40 to 03:18 UT.
Nineteen 5-minute exposures were obtained in the R-band.
Conditions were photometric, and the Landolt standard-star field
around PG0231+051 was used for calibration.  The afterglow magnitudes
measured for the first and last exposures of the sequence are:

                --------------------------------
                 Jan 1 UT  t-t0(hr)   R    +/-
                --------------------------------
                  01:40     20.92   18.48  0.02
                  03:18     22.55   18.61  0.02
                --------------------------------

The following stars in field were calibrated, and can be used for
comparison:

           -----------------------------------------
            Star  R.A.(2000)   Decl.(2000)      R
           -----------------------------------------
             A    00 42 30.4    -01 36 13     16.07
             B    00 42 11.7    -01 37 29     17.95
             C    00 42 15.9    -01 39 08     17.92
             D    00 42 20.0    -01 41 53     17.22
             E    00 42 28.8    -01 40 16     17.96
           -----------------------------------------