[vsnet-grb-info 2573] GRB 051227: Gemini observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4410
SUBJECT: GRB 051227: Gemini observations
DATE:    05/12/28 17:56:26 GMT
FROM:    Edo Berger at Carnegie Obs  <eberger at ociw.edu>

E. Berger (Carnegie Observatories) reports:

"We imaged the error circle of GRB 051227 (GCNs 4397,4401) with GMOS on
the Gemini-north telescope starting on 2005, Dec. 28.33 UT (13.88 hr after
the burst).  A total of 25 min were obtained in r-band in good seeing
conditions (0.75").  Within the refined XRT position (GCN 4402) we detect
source S1 (GCNs 4404,4407,4408) at coordinates (J2000):
        RA = 08:20:58.107
        DEC= +31:55:32.01

We also detect an additional faint source about 0.7" outside of the XRT
error circle (S2) which is not clearly visible in the finders provided by
Malesani et al.  (GCN 4407) and Bloom et al. (GCN 4408) at coordinates:
        RA = 08:20:57.773
        DEC= +31:55:26.67

Using several nearby stars with SDSS calibration (GCN 4399) we determine
that source S1 has r=24.8+/-0.15 mag, while source S2 has r=25.5+/-0.25
mag.  Since previous GCNs do not provide photometry of source S1 we are
unable to determine whether it has varied in brightness compared to 
earlier observations.

A finding chart showing objects S1 and S2 is available at:
        http://www.ociw.edu/~eberger/grb051227-gemini.ps

Further Gemini observations are planned."