TITLE:   GCN CIRCULAR
NUMBER:  16769
SUBJECT: GRB140903A: Discovery Channel Telescope Optical Detection
DATE:    14/09/04 05:28:27 GMT
FROM:    John Capone at UMD  <jicapone@astro.umd.edu>

J. Capone (UMD), V. Toy (UMD), S.B. Cenko (NASA-GSFC), A. Cucchiara
(NASA-GSFC), E. Troja (NASA-GSFC), A. Kutyrev (NASA-GSFC), S. Veilleux
(UMD), and S. Gezari (UMD) report on behalf of a larger collaboration:

We observed the field of GRB140903A (Cummings et al., GCN 16763) with the
Large Monolithic Imager (LMI) on the 4.3m Discovery Channel Telescope (DCT)
at Happy Jack, AZ. We observed in r' for a total of 600 seconds beginning
at 2014-09-04 03:10 UTC (approximately 12 hours after the Swift trigger).

A source is clearly detected at the location of the x-ray afterglow (De
Pasquale et al, GCN 16767). Using nearby point sources from SDSS for
calibration, we measure a preliminary magnitude of r' = 20.2 +/- 0.3. This
value is not corrected for Galactic extinction in the direction of the GRB.
 We also note the presence of a 9th magnitude star ~10 arcseconds from the
afterglow candidate.

We thank the staff of the Discovery Channel Telescope for assistance with
these observations.