TITLE:   GCN CIRCULAR
NUMBER:  33188
SUBJECT: GRB 230116D: LCOGT Optical Upper Limit
DATE:    23/01/17 15:59:16 GMT
FROM:    Robert Strausbaugh at University of Minnesota  <rstrausb@umn.edu>

R. Strausbaugh (University of Minnesota), A. Cucchiara (NASA) report on
behalf of a larger collaboration:

We observed the GRB 230116D (Sonbas et al., GCN 33176) field with the LCOGT
1-meter Sinistro instrument at the McDonald Observatory, TX, USA site, on
January 17, from 05:24 to 05:56 UT (corresponding to 8.33 to 8.64 hours
from the GRB trigger time) with the SDSS r and i filters.

We performed a series of 3x300s exposures in each band.  We do not detect a
source in either band within the XRT enhanced error region (Osborne et al.,
GCN 33180).  This suggests fading compared to other optical detections (Zhu
et al., GCN 33177; Nazarov et al., GCN 33178; Moskvitin et al., GCN 33179;
Swain et al., 33182).

The following magnitudes and upper limits are calculated using the
PanSTARRS catalog as reference:

r > 22.2
i > 21.2

These magnitudes are not corrected for galactic extinction.