[vsnet-grb-info 26038] GRB 200716C: Optical observations from HCT

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28138
SUBJECT: GRB 200716C: Optical observations from HCT
DATE:    20/07/18 12:03:42 GMT
FROM:    Brajesh Kumar at Indian Inst. of Astrophysics  <brajesh.kumar at iiap.res.in>

Brajesh Kumar (ARIES, Nainital), Anirban Dutta, Avinash Singh, G. C. 
Anupama, D. K. Sahu and Pramod Kumar (IIA, Bengaluru)

We observed the field of GRB 200716C (Fermi GBM, GCN #28123; Ukwatta et 
al., GCN #28124) with the Himalaya Faint Object Spectrograph and Camera 
(HFOSC) mounted on the 2-m Himalayan Chandra Telescope (IAO, Hanle, 
India). Multiple frames (each 300 sec) of the GRB field in Bessell R and 
I bands were obtained under moderate sky conditions. Preliminary PSF 
photometry on the stacked images was performed and calibrated against 
USNO-B1 catalogue. The estimated magnitudes are listed below:

   DATE     | UT (mean) | Exposure | Filter |  Mag
2020-07-17   17:06:34     300x3        R     17.55 +/- 0.18
2020-07-17   17:23:33     300X3        I     17.19 +/- 0.15

Here, we caution that there is an extended object near the GRB location 
(possibly the host galaxy, D'Avanzo et al. GCN #28132). However, the 
extended source is fainter (~19.23 and ~18.67 mag in R and I bands, 
respectively, USNO-B1). Therefore, the estimated magnitudes likely 
belong to the OT candidate (Lipunov et al., GCN #28125; Hu et al., GCN 
#28126), affected by the host contamination.

We thank the staff at IAO and CREST for helping with the observations.