[vsnet-grb-info 13334] GRB 130515A: Further Gemini Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14670
SUBJECT: GRB 130515A: Further Gemini Observations
DATE:    13/05/16 23:23:55 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko at srl.caltech.edu>

S. B. Cenko (UC Berkeley) and A. Cucchiara (UCSC) report on behalf of a
larger collaboration:

We re-imaged the field of GRB 130515A (Malesani et al., GCN 14650) with
the Gemini Multi-Object Spectrograph mounted on the 8 m Gemini South
telescope.  Images were obtained in the r' filter beginning at 4:38 UT on
2013 May 16 (~ 1.1 days after the Swift trigger).

Comparing with our previous epoch of observations (Cenko et al., GCN
14656), we find no evidence for variability in or around the enhanced XRT
error circle (Beardmore et al., GCN 14654).  Specifically, we note that
the three sources S1, S2, and S3 identified previously (Xu et al., GCN
14653, Schmidl et al., GCN 14655, Levan et al., GCN 14677) all maintain a
constant brightness level.  Using digital image subtraction, we limit the
optical afterglow at the time of our first epoch of observations (~ 38 min
after the Swift trigger) to be R > 23.7 mag (calibrated with respect to
nearby USNO-B1 point sources).

We thank the Gemini staff for the prompt execution of these observations.