Skip to main content
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 34667

GRB230911C: LCOGT Optical Upper Limits
2023-09-11T20:58:29Z (10 months ago)
Robert Strausbaugh at Eastern Illinois University <>
R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:

We observed the Swift GRB 230911C (Sonbas et al., GCN 34655) field with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory site, on September 11, from 17:20 to 17:52 UT (corresponding to 8.55 to 9.08 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 within the Swift-XRT enhanced error region (Evans et al., GCN 34658) in either band.

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

r > 21.6
i > 21.1

These magnitudes are not corrected for galactic extinction.

Looking for U.S. government information and services? Visit