[vsnet-grb-info 25401] GRB 200405B: LCO Optical Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27501
SUBJECT: GRB 200405B: LCO Optical Upper Limits
DATE:    20/04/06 19:41:26 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh at 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 Swift/BAT-GUANO GRB 200405B (DeLaunay et al., GCN 27497) with the LCO 1-m Sinistro instrument at the Siding Spring Observatory, Australia site, on April 6, from 08:49 to 09:29 UT (corresponding to 28.9 to 29.6 hours from the GRB trigger time) with the Bessel I and R filters.

We performed a series of 5x240s exposures in I and R. We do not detect any fading sources in the individual frames (or in stacked images).  We also do not detect any optical counterparts to the 4 potential Swift XRT candidates (Sbarufatti et al., GCN 27500).  Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits:

R > 21.75

I > 20.86

These magnitudes are not corrected for galactic extinction.

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