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 32325

GRB220701A: VIRT Optical Upper Limit
2022-07-05T17:51:12Z (2 years ago)
Priyadarshini Gokuldass at U. of the Virgin Islands <>
P. Gokuldass (Florida Institute of Technology), N. Orange (OrangeWave
Innovative Science, LLC), K. Noonan (UVI), R. Querrard (UVI), K. Smith
(UVI), D. Morris (UVI) report:

We observed the field of GRB220701A (Evans et al., GCN 32306) with the 0.5m
Virgin Island Robotic Telescope (VIRT) at the University of the Virgin
Islands' Etelman Observatory on 07-01-2022 starting at 05:16:18.64 UT (T+24
min). We performed a series of exposures in the R filter with a total
exposure of 3300 s. The weather conditions were partly cloudy during the
hours of observation with an average airmass of 2.

We detect no new source within the enhanced XRT position error circle
(Evans et al., 32308), consistent with other non-detections (Zheng et al.
GCN 32307;  O'Connor  et al. GCN 32309; Oates  et al. GCN 32310; Hu et al.
GCN 32311; Strausbaugh et al. GCN 32313; Belkin et al. GCN 32317) and
report the following 5-sigma upper limit:

T_mid            ||Exposure     ||Filter      ||Limit

T+ 1.5 hrs      ||3300s         ||R          ||>19.8

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

We acknowledge financial support from NASA MUREP MIRO award 80NSSC21M0001, NASA
EPSCoR award 80NSSC19M0060, and NSF EiR award 1901296.This message can be
Looking for U.S. government information and services? Visit