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 31027

GRB 211024A: 1.3m DFOT observations
2021-11-01T15:36:39Z (3 years ago)
Dimple Panchal at ARIES, India <>
Ankur Ghosh, Rahul Gupta, Dimple, Amit Kumar, Amit Ror, Amar Aryan, Arvind
K. Dattatrey, Shubham Kishore, Tushar Tripathi, S. B. Pandey, and Kuntal
Misra (ARIES) report:

We observed GRB 211024A which was triggered by Fermi GBM (Fermi GBM Team,
GCN 30962), and further, follow up observations were carried out by
Swift/BAT-GUANO (A. Tohuvavohu et al., GCN 31006)), 0.7m GROWTH-India
Telescope (GIT, Kumar et al,. (GCN 31014)), using 1.3m Devasthal Fast
Optical Telescope (DFOT) located at Devasthal observatory of Aryabhatta
Research Institute of Observational Sciences (ARIES), India. Our
observation was carried out in two epochs. The first epoch observation was
started on 2021-10-26 at 16:22:24, i.e., ~2.62 DAYS post-Fermi trigger
whereas the second epoch observation was started on 2021-10-27 at 17:43:00,
i.e., ~3.68 days the Fermi trigger. Multiple frames in the R filter were
taken in both epochs.

In the first epoch, we started observing the location mentioned in
Swift/BAT-GUANO A. Tohuvavohu et al., (GCN 31006). But we found no
uncatalogued source within the error circle of ~ 6 arcmin up to 22.73 mag.

In the second epoch, we continued our observation for the 4th X-ray source
given by Swift-XRT ToO observations (M. Perri et al. GCN 31013) which were
assumed to be the afterglow of Fermi GBM GRB 211024A (GCN 30962), A.
Tohuvavohu et al., (GCN #31006), with 0.7m GROWTH-India Telescope (GIT,
Kumar, et al,. (GCN 31014)). We detected one source at R.A.= 1:52:46.98 ,
DEC.= -7:00:27.30 which is coincident with an X-ray source (#4) by
Swift-XRT ToO observations (M. Perri et al. GCN 31013. However, the source
is not variable during our observation period. Hence this is not the optical
counterpart of GRB 211024A. We quote an upper limit of 22.54 mag.

These magnitudes are not corrected for the Galactic extinction in the
direction of the burst. The standard stars from the USNO-B1.0 catalog was
used to get the calibrated magnitude.

This circular may be cited.
Looking for U.S. government information and services? Visit