[vsnet-grb-info 26611] GRB 201020A: GROWTH-India Telescope optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28711
SUBJECT: GRB 201020A: GROWTH-India Telescope optical observations
DATE:    20/10/21 02:17:35 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb at iitb.ac.in>

H. Kumar(IITB), J. Stanzin (IIA), V. Bhalerao(IITB), G. C. Anupama(IIA), S. Barway(IIA), report on behalf of the GROWTH-India collaboration:

We followed up GRB 2010210A (E. Ambrosi et al., GCN #28696; also see:- R. Adachi et al., GCN #28697; J.P. Osborne et al., GCN #28698; V. Lipunov et al., GCN #27800, S.Y. Fu et al., GCN #28701; S. Belkin et al., GCN #28703 and T. Pankov et al., GCN #28708) with 0.7m GROWTH-India telescope. We obtained 300-sec exposures in the SDSS r’ filter starting at 2020-10-20T13:00:50.42 UT (~7.22 hrs after the burst). We clearly detected uncataloged sources at a position consistent with E. Ambrosi et al., GCN #28696.
Here are the photometric results from GIT observations:-  
------------------------------------------------------------------
 JD (END) | T_end-T0(hrs) | Filter | Mag |
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2459143.04576 | 7.31 |  r  |  19.43 +/- 0.06
2459143.04943 | 7.39 |  r  |  19.49 +/- 0.05
2459143.05670 | 7.57 |  r  |  19.52 +/- 0.04
2459143.06046 | 7.66 |  r  |  19.59 +/- 0.04
2459143.06406 | 7.75 |  r  |  19.63 +/- 0.04
2459143.06764 | 7.83 |  r  |  19.65 +/- 0.04
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Combining our photometric results with r’ measurements of S.Y. Fu et al., (GCN #28701), S. Belkin et al., (GCN #28703), and T. Pankov et al., (GCN #28708) we conclude that the source is fading with a power-law index of 1.6 +/- 0.2. Given the fast fading, we encourage the follow-up of the source. The magnitudes are 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 and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).