GCN Circular 23195
Subject
GRB 180904A: NOT optical observations, candidate host galaxy
Date
2018-09-04T23:04:27Z (6 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
Daniele Malesani (DAWN/NBI and DARK/NBI), Kasper Elm Heintz (Univ.
Iceland and DAWN/NBI), Sune Dyrbye (NOT), report on behalf of a largert
collaboration:
We observed the field of GRB 180904A (D'Ai' et al., GCN 23194) with the
Nordic Optical Telescope (NOT) equipped with the AlFOSC camera.
In an image of 300 s exposure taken with the SDSS r filter and
commencing on Sep 4.9057 UT (15.6 min after the GRB), we detect a single
object consistent with the currently available XRT position
(http://www.swift.ac.uk/xrt_positions/). Its coordinates are (J2000):
RA = 18:16:59.74
Dec = +46:37:47.1
Compared to nearby stars from the Pan-STARRS survey, we measure for this
object a magnitude r = 22.56 +- 0.08 AB.
We note that the same object is visible in the archival Pan-STARRS image
of this field, with a measured magnitude r = 22.84 +- 0.15 AB. There is
thus only marginal indication of excess flux in the NOT image. If this
object is related to GRB 180904A, as suggested by the spatial
coincidence with the X-ray position, it is largely or entirely dominated
by the host galaxy.
Further observations are planned.