GCN Circular 26176
Subject
GRB191016A GROND observations
Event
Date
2019-11-05T15:45:33Z (6 years ago)
From
Patricia Schady at Swift <p.schady@bath.ac.uk>
P. Schady (Univ. of Bath) and J. Bolmer (MPE Garching) report:
We observed the field of GRB 161019A (Swift trigger 929744; Gropp et al., GCN #26008) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).
Observations started at 04:19 UT on 2019-10-16, 10 min after the GRB trigger. They were performed at an average seeing of 1.7" and at an average airmass of 1.7.
We detect a bright point source in all optical and near-infrared filters consistent with the reported optical afterglow position (Watson et al., GCN #26010; Siegel et al., GCN #26024). Based on the first 3.3 min of total exposures in g'r'i'z'JHK, we estimate preliminary AB magnitudes of
g' = 16.81 +/- 0.03
r' = 16.33 +/- 0.03
i' = 15.84 +/- 0.04
z' = 15.51 +/- 0.04
J = 15.28 +/- 0.05
H = 14.80 +/- 0.05
K = 14.83 +/- 0.08
Given magnitudes are calibrated against SDSS and 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.09 in the direction of the burst (Schlafly & Finkbeiner 2011).
We acknowledge the excellent support provided by the telescope operator at La Silla.