GCN Circular 30193

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
Not found
 
 
). We detect an uncatalogued source consistent with
the OT reported by Swift UVOT (Page et al.; GCN 30170
Not found
 
 
) 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
Not found
 
 
, Kumar et al.;
GCN 30174
Not found
 
 
, Rumyantsev et al.; GCN 30175
Not found
 
 
, 30178
Not found
 
 
, Hu et al.;
GCN 30177
Not found
 
 
, de Wet et al.; GCN 30180
Not found
 
 
, Romanov; GCN 30181
Not found
 
 
,
Fynbo et al.; GCN 30182
Not found
 
 
, Moskvitin et al.; GCN 30187
Not found
 
 
, Osborne
Et al.; GCN 30189
Not found
 
 
, Becerra et al.; GCN 30190
Not found
 
 
).

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)