[vsnet-grb-info 27170] GRB 210104A: SARA-KP 0.9m Optical Afterglow Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29273
SUBJECT: GRB 210104A: SARA-KP 0.9m Optical Afterglow Detection 
DATE:    21/01/06 22:01:36 GMT
FROM:    Samalka Anandagoda at Clemson University  <iananda at g.clemson.edu>

S. Anandagoda, S. Geier, K. Pellegrin and D. Hartmann report:

We observed the field of GRB 20210104A (Fermi GBM Team, GCN 29232; Troja et al., GCN 29233; Biltzinger et al., GCN 29234) using the SARA 0.9m optical telescope located at Kitt Peak, AZ, USA, equipped with the Alta-E6-1105 camera. Observation started at 06:20:04 UTC on 2021-01-05 and ended at 09:34:43 UTC (~ 18 to 21 hours after the detection of the burst by the Fermi GBM Team). We obtained a series of 120s exposure frames in the Bessell R filter. We clearly detect the optical afterglow of GRB 20210104A at the enhanced Swift-XRT position (Beardmore et al., GCN 29245).

The estimated magnitude of the GRB afterglow was 20.61 found by stacking 20 images of 120s each in the Bessell R band filter.

T_start-T0 (hrs)   T_end-T0 (hrs)     Start Date (UTC) 	  Filter 	Magnitude (mag)
—————————————————————————————-------------------------
----------------------------------------------------------------------------------------------------------------
18:53		      19:33	         2021-01-05T06:20:04       R 	   20.61


Photometry is done based on the USNO-B1.0 catalog.

The Southeastern Association for Research in Astronomy (SARA) consortium operates three telescopes: the 0.9-m SARA-KP at Kitt Peak in Arizona, and the 0.6-m SARA-CT at Cerro Tololo in Chile, and the 1.0-m SARA-RM (formerly the JKT) telescope at Roque de los Muchachos Observatory in the Canary Islands. For more information see: Keel et al. (2016): https://iopscience.iop.org/article/10.1088/1538-3873/129/971/015002