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GCN Circular 22684

GRB 180504A: NOT afterglow candidate
2018-05-05T07:05:30Z (6 years ago)
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <>
D. Malesani (DAWN/NBI and DARK/NBI) and Illa R. Losada (NOT, Nordita, 
Stockholm Univ.) report on behalf of a larger collaboration:

We observed the field of GRB 180504A (Lien et al., GCN 22682) with the 
Nordic Optical Telescope equipped with the AlFOSC camera. The field has 
a bad visibility from La Palma, and observations were carried out at 
large airmass (~2) and straddling twilight. The average seeing was 1.5".

Coincident with the UVOT-enhanced position reported by Evans (GCN 
22683), we note the presence of a faint source, at a position (J2000; 
0.5" error):

RA = 22:04:34.61
Dec = -14:39:30.0

We note that the automatically reported un-enhanced XRT position 
(available from is at the time of 
writing significantly different from the one quoted in the GCN, and 
would not include our afterglow candidate.

Photometry of the candidate against nearby stars from the Pan-STARRS 
survey yields r = 22.5 +/- 0.3 (AB) at a mean time 2018 May 5.222 UT 
(9.57 hr after the trigger)

Further observations are planned.
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