TITLE:   GCN CIRCULAR
NUMBER:  37816
SUBJECT: GRB 241006A: VIRT Optical Upper Limit
DATE:    24/10/18 16:58:56 GMT
FROM:    Priya Gokuldass at ERAU <gokuldap@my.erau.edu>

K. Noonan (UVI), P. Gokuldass (ERAU), N. Orange (OrangeWave Innovative Science, LLC), D. Morris (NASA), T. Lombardi (Eckerd College), F. George (ERAU), R. Querrard (UVI), D. Smith (UVI), K. Smith (UVI) report:

We observed the field of GRB241006A (Gupta et al., GCN 37722) with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 2024-10-07 starting at 23:05:40.9 (Tmid+25.7 hrs). We performed a series of exposures in an R filter with a total exposure of 3490s. The weather conditions were partly cloudy during the hours of observation with an average airmass of 1.9. 

We do not detect any source within the enhanced XRT position (Beardmore  et al. GCN 37724). This non-detection is consistent with the upper limits reported by SWIFT/UVOT (Kuin et al., GCN 37729), PRIME (Durbak et al., GCN 37730), GRANDMA (Hussenot-Desenonges et al., GCN 37738), and SVOM/VT (Qiu et al., GCN 37728). We report the following 3-sigma upper limit:

T_mid                ||Exposure   ||Filter   ||Limit 
T+ 25.7 hrs          || 3490s     || R       ||>20.46

The limit is estimated from comparison to nearby USNO B1 stars and is not corrected for Galactic extinction. The VIRT is still in the commissioning phase. 

We acknowledge financial support from NASA EPSCoR award 80NNSC22M0063, NSF PAARE award 2319415, and NASA EPSCoR award 80NSSC24M0112. This message can be cited.