TITLE:   GCN CIRCULAR
NUMBER:  27637
SUBJECT: GRB 200424A: LCO Optical Upper Limit
DATE:    20/04/24 20:24:56 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh@uvi.edu>

R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration:

We observed INTEGRAL GRB 200424A (Mereghetti et al., GCN 27634) with the LCO 1-m Sinistro instrument at the Siding Spring Observatory, Australia site, on April 24, from 18:48 to 19:23 UT (corresponding to 6.68 to 7.27 hours from the GRB trigger time) with the Bessel I and R filters.

We performed a series of 5x240s exposures in R and 4x240s in I. We do not detect any fading sources in the individual frames (or in stacked images).  Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits:

R > 24.83

I > 22.93

These magnitudes are not corrected for galactic extinction.

R.S. is funded by NSF AST grant #1831682