TITLE:   GCN CIRCULAR
NUMBER:  28639
SUBJECT: GRB 201015A: GOTO confirmation of afterglow detection
DATE:    20/10/16 03:18:47 GMT
FROM:    Kendall Ackley at Monash University  <kendall.ackley@monash.edu>

K. Ackley (1); D. K. Galloway (1); Y-L Mong (1); M. Dyer (2); J. Lyman (3);
K.
Ulaczyk (3); D. Steeghs (3); V. Dhillon (2); P. O'Brien (4); G. Ramsay
(5); S. Poshyachinda (6); R. Kotak (7); L. Nuttall (8); D. Pollacco
(3); R. Breton (9)
((1) Monash University, (2) University of Sheffield, (3) Warwick
University, (4) University of Leicester, (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 201015A
(Swift; D'Elia et al; GCN 28632).

We made a series of 4x90 s exposures using our wide L-band filter
(400-700 nm) covering the Swift XRT error box (Swift; Kennea et al.; GCN
28635),
beginning at 51 minutes after trigger, with midtime of the
first observation 23:41:54.25 UT on 15 October 2020.

Using a difference imaging analysis with recent survey observations of
the same pointings as reference, we detect an uncatalogued source
located at (J2000):
RA 23:37:16.42
Dec +53:24:55.89
confirming the OT reported by MASTER (Lupinov et al.; GCN 28633) and
NOT (Malesani et al.; GCN 28637). We find an equivalent magnitude of
g ~ 20.2 mag based on cross-calibration of our L-band magnitudes
against the ATLAS catalogue.

Observations are continuing.

GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC) (https://goto-observatory.org
<https://goto-observatory.org/>)