Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 30674

Subject
GRB 210820A: LT optical upper limit
Date
2021-08-21T17:30:40Z (3 years ago)
From
Martin Blazek at HETH/IAA-CSIC <alf@iaa.es>
M. Blazek, D. A. Kann (both HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/
IAA-CSIC, DARK/NBI), C. C. Thoene, J. F. Agui Fernandez (both HETH/IAA-CSIC)
report:

We observed the location of the Swift GRB 210820A (Beardmore et al., GCN
#30664) with 2-m Liverpool Telescope located in La Palma, Canary Isands,
Spain. We obtained 15 x 60 s images beginning 2021-08-21 03:29:30 UT. In
a stack of all images, centered at 0.4175 days after the GRB, no source is
detected at the UVOT position. Measured against three nearby SDSS stars, we
derive an upper limit of r' > 21.1 mag. This agrees with the non-detections
reported by Lipunov et al. (GCN #30666), Fu et al. (GCN #30669)., and Zhu et
al. (GCN #30670).
Looking for U.S. government information and services? Visit USA.gov