GCN Circular 30200

A. Dutta (IIA), H. Kumar (IITB), D. K. Sahu (IIA), B. Kumar (ARIES), G. C.
Anupama (IIA), V. Bhalerao (IITB), S. Barway (IIA) report on behalf of a
larger Indian collaboration:

We obtained a spectrum of the GRB 210210A detected by Swift-BAT ( K. L.
Page et al., GCN #30160), with the HFOSC instrument mounted on the 2-m
Himalayan Chandra Telescope at the Indian Astronomical Observatory. We
obtained a wavelength coverage of 3800 - 8000 angstrom. We took a 2700
second exposure on 2021 June 10 16:48 (UTC).

The spectrum is continuum-dominated with a broad absorption feature at
~5509 A which we interpret as Lyman alpha (rest-frame wavelength 1216 A) at
a redshift of z=3.5, consistent with the redshift reported by Zhu et al.
(GCN #30164. Other absorption features due to Si II (1307 A), Si IV (1397
A), CIV (1549 A) at the same redshift are also observed. The spectrum has
not been corrected for reddening.

We thank the staff at IAO and CREST, Hosakote, for helping with the
observations. The Indian Astronomical Observatory and CREST are operated by
the Indian Institute of Astrophysics, Bengaluru, India.