GCN Circular 32363
Subject
GRB 220708B: GIT optical upper limits
Event
Date
2022-07-11T11:45:05Z (4 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
V. Swain (IITB), H. Kumar (IITB), K. Angail (IAO), V. Bhalerao (IITB), G. C. Anupama (IIA), S. Barway (IIA) report on behalf of the GIT team:
We observed GRB 220708B detected by Swift (Tohuvavohu et al., GCN 32345; Evans et at., GCN 32350), CALET GBM (Kawakubo et al., GCN 32356) and Konus-Wind (Frederiks et al., GCN 32358), with the 0.7m GROWTH-India Telescope (GIT). The observations started at 21:04:33 UT on 2022-07-08, 18.96 hours after the Swift trigger. We obtained multiple 300-sec exposures in the g���, r' and i��� filters. We did not detect any new source in our stacked images within the 4 arcsec radius circle around R.A.= 16h 34m 18.97s, Dec.= +36d 20' 52.0��� (Osborne et al. GCN #32350). The obtained upper limits follow as:
-------------------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) |
-------------------------------------------------------------------
2459769.38578312 | 19.14 | 4 x 300 (stacked) | g' | > 21.03 |
2459769.39333163 | 19.32 | 4 x 300 (stacked) | r' | > 20.99 |
2459769.41415129 | 19.82 | 4 x 300 (stacked) | i' | > 19.83 |
-------------------------------------------------------------------
These upper limits are consistent with Jiang et al.(GCN #32355), Turpin et al.(GCN #32360). The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.