Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 33217

GRB 230123A: LCOGT Optical Upper Limits
2023-01-24T17:19:20Z (a year ago)
Robert Strausbaugh at University of Minnesota <>
R. Strausbaugh (University of Minnesota), A. Cucchiara (NASA) report on
behalf of a larger collaboration:

We observed the GRB 230123A (Williams et al., GCN 33206) field with the
LCOGT 1-meter Sinistro instrument at the Cerro Tololo Interamerican
Observatory, Chile site, on January 24, from 02:06 to 02:38 UT
(corresponding to 15.78 to 16.32 hours from the GRB trigger time) with the
Bessel 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 (Beardmore et
al., GCN 33209), consistent with other optical upper limits (Gendre et al.,
GCN 33208; Belles et al., 33211).

The following upper limits are calculated using the USNO-B1.0 catalog as

R > 20.8
I > 20.1

These magnitudes are not corrected for galactic extinction.
Looking for U.S. government information and services? Visit