[vsnet-grb-info 28090] GRB 210610B: GOTO confirmation of afterglow detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30193
SUBJECT: GRB 210610B: GOTO confirmation of afterglow detection
DATE:    21/06/11 08:16:32 GMT
FROM:    Travis Mong at Monash University  <yik.mong at monash.edu>

Y-L Mong (1); K. Wiersema (2); R. Starling (3); K. Ackley (1);
M. Dyer (4); D. K. Galloway (1); J. Lyman (2); K. Ulaczyk (2);
D. Steeghs (2); V. Dhillon (4); P. O'Brien (3); G. Ramsay (5);
S. Poshyachinda (6); R. Kotak (7); L. Nuttall (8); D. Pollacco (2);
R. Breton (9)

((1) Monash University, (2) Warwick University, (3) University of
Leicester, (4) University of Sheffield, (5) Armagh Observatory &
Planetarium, (6) National Astronomical Research Institute of Thailand, (7)
University of Turku, (8) University of Portsmouth, (9) University of
Manchester) report on behalf of the GOTO collaboration:

We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO) on La Palma in response to GRB 210610B (Page
et al; GCN 30170). We detect an uncatalogued source consistent with
the OT reported by Swift UVOT (Page et al.; GCN 30170) and other
facilities.

We made a series of 4x90 s exposures using our wide L-band
filter(400-700 nm) beginning around ~4hrs after the trigger, with
midtime of the first observation 23:50:18.136 UT on 10 June 2021.

We detect an uncatalogued source located at (J2000):

RA 16:15:40.369Dec +14:23:57.19

confirming the OT (Page et al.; GCN 30170, Kumar et al.;
GCN 30174, Rumyantsev et al.; GCN 30175, 30178, Hu et al.;
GCN 30177, de Wet et al.; GCN 30180, Romanov; GCN 30181,
Fynbo et al.; GCN 30182, Moskvitin et al.; GCN 30187, Osborne
Et al.; GCN 30189, Becerra et al.; GCN 30190).

We find an equivalent magnitude of g = (17.86 +/- 0.05) mag based
on calibration against PanSTARRS DR1 photometry in ATLAS_REFCAT2
(Tonry et al. 2018).

Observations are continuing.

GOTO is operated at the La Palma observing facilities of the
Universityof Warwick on behalf of a consortium including the
University ofWarwick, Monash University, Armagh Observatory, the
University ofLeicester, the University of Sheffield, the National
AstronomicalResearch Institute of Thailand (NARIT), Turku University,
Portsmouth
University, Manchester University and the Instituto de Astrofisicade
Canarias (IAC) (https://goto-observatory.org)