TITLE: GCN CIRCULAR NUMBER: 31027 SUBJECT: GRB 211024A: 1.3m DFOT observations DATE: 21/11/01 15:36:39 GMT FROM: Dimple Panchal at ARIES, India dimplepanchal96@gmail.com
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.