[vsnet-grb-info 632] GRB021211: APO optical observations

[GCN Circulars <gcncirc@lheawww.gsfc.nasa.gov>]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1765
SUBJECT: GRB021211: APO optical observations
DATE:    02/12/17 23:23:11 GMT
FROM:    Don Lamb at U.Chicago  <lamb@oddjob.uchicago.edu>

D. Q. Lamb, M. C. Nysewander, D. E. Reichart, J. C. Barentine, C. Laws,
D. G. York, and R. J. McMillan report,

We have calibrated our i* image of the optical transient and host
galaxy of GRB021211 (Crewe et al., GCN 1734), taken with the ARC
3.5-meter telescope at APO beginning at 09:19 UT on December 12 (Lamb
et al., GCN 1744).  Using the photometric calibration reported by A.
Henden (GCN 1753) and a 1" aperture, we measure i* = 23.0 +/- 0.20 mag
for the optical afterglow.  This value may be subject to some
systematic error because of the presence of the host galaxy, which is
visible as an extension to the northeast of the afterglow (Lamb et al.,
GCN 1744; McLeod et al., GCN 1750; Levan et al. GCN 1758; Caldwell et
al., GCN 1759).  Conservative upper limits on the brightness of the
host galaxy are i* > 24.1 mag (1 sigma), > 23.4 mag (2 sigma), and >
23.0 mag (3 sigma).  Second epoch observations of the GRB021211 field
are planned that will enable us to refine these values.

An i* image of the GRB021211 field, showing the optical afterglow and
the host galaxy on the night of Dec 12th can be found at

http://astro.uchicago.edu/home/web/lamb/grb021211/apo/ot_and_host.jpg

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