[vsnet-grb-info 3236] GRB 060502b: Gemini imaging and spectroscopy

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5071
SUBJECT: GRB 060502b: Gemini imaging and spectroscopy
DATE:    06/05/03 17:52:27 GMT
FROM:    Edo Berger at Carnegie Obs  <eberger at ociw.edu>

E. Berger (Carnegie Observatories), S. B. Cenko and A. Rau (Caltech)  
report on behalf of a larger collaboration:
                                                                                        
"We used the GMOS instrument on the Gemini North Telescope to image the
field of GRB 060502b (GCN 5064) and to obtain a spectrum of the object
detected within the XRT error circle (GCN 5063) by Halpern and Mirabal
(GCN 5066).  We detect the latter object in a combined 1500 sec exposure
with an r-band magnitude of about 21.8, suggesting that the object has not
faded between the time of the MDM observation (15 hrs post burst) and our
observation (17 hrs post burst).  Moreover, a spectrum of the object
reveals broad absorption bands centered on 5900, 6200, and 6700 A, which
are typical of cool giants (a comparison to stellar spectra indicates a
M2V - M4V classification).

In addition to this star, we also identify a fainter and marginally
extended object within the XRT error circle with r~24.7 mag located at
(J2000):
        RA =  18:35:46.06
        DEC= +52:37:51.46
with an uncertainty of about 0.3" in each coordinate.
                                                                                        
An image of the region centered on the XRT error circle is available at:
        http://www.ociw.edu/~eberger/grb060502b_gemini.gif
Source "S1" is the object found by Halpern and Mirabal (shown here to be a
star), and source "G1" is the faint galaxy discussed above."