TITLE:   GCN CIRCULAR
NUMBER:  29176
SUBJECT: GRB 201223A: HCT optical upper limit
DATE:    20/12/26 05:51:35 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13@gmail.com>

H. Kumar(IITB), D. K. Sahu (IIA), V. Bhalerao(IITB), G. C. Anupama(IIA), S.
Barway(IIA) report on behalf of the HCT team:

We observed GRB 201223A detected by Swift-BAT (J.D. Gropp et al., GCN
#29158); optical counterpart first reported by V. Lipunov et al., (GCN
#29157) with 2.0m Himalayan Chandra Telescope (HCT). We obtained a series
of 180-sec exposures in the Bessell R filter and did not detect the
afterglow in our stacked image. We obtained the following upper limit:

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JD (mid) | T_mid-T0(hrs) | Exposure | Filter | Lim_mag (5-sigma) |

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2459208.4569 | 28.99 | 180*10 (stacked) | Bessell R | > 22.49 |

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Our upper limit is consistent with power-law decay extrapolation suggested
by D. Xu et al., (GCN #29169), Kumar et al., (GCN #29168).


These observations were carried out under the ToO program "HCT-2020-C3-P6".
We thank HCT staff for undertaking the observations.