[vsnet-grb-info 10013] GRB 101219A: Further Gemini-South Imaging

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11468
SUBJECT: GRB 101219A: Further Gemini-South Imaging
DATE:    10/12/19 11:52:37 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko at srl.caltech.edu>

S. B. Cenko (UC Berkeley), A. J. Levan (Warwick), R. Chornock, E. Berger
(Harvard),  D. A. Perley, J. S. Bloom (UC Berkeley), and N. Tanvir
(Leicester) report on behalf of a larger collaboration:

We have obtained a second series of i'-band imaging (Perley et al., GCN
11464) of the field of the short-hard GRB101219A (Gelbord et al., GCN
11461) with the Gemini Multi-Object Spectrograph mounted on the 8-m Gemini
South telescope.  Observations consisted of 12 x 180 s exposures beginning
at 6:55 UT (~ 4.2 hours after the burst trigger).

Digital subtraction of the two epochs reveals no transient emission within
or around the XRT error circle.  Using several common SDSS objects for
calibration, we place an upper limit of i' > 24.5 mag.  Similarly,
aperture photometry reveals the source mentioned by Perley et al. (GCN
11464), which is clearly extended in our images, remains approximately
constant over this time period, with an i-band magnitude of ~ 23.5.

We further note that no sources are present in any filter in the SDSS
pre-explosion imaging of the field in the immediate environment of the XRT
error circle.  The limits, however, would not be sufficient to detect the
extended source mentioned above.