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GCN Circular 26066

GRB 191024A: GROND early upper limits
2019-10-24T13:47:49Z (5 years ago)
Jan Bolmer at MPE/Garching <>
J. Bolmer (MPE Garching), and P. Schady (Univ. of Bath),  report:

We observed the field of GRB 191024A (Swift trigger 931242; Page et al., GCN #26063)
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 04:45:40 UT on 24th October, 3 minutes after the GRB trigger.
They were performed at an average seeing of 1.2" and at an average airmass of 1.4.

We do not detect a source at the enhanced position of the Swift-XRT afterglow
(Beardmore et al., GCN #26064) ��� down to the following 3-sigma limits (all AB magnitude) ��� 
in the stacked images of observations taken between 168 and 5906 seconds post trigger
(total integration time of 95 min).

g' > 25.5 mag
r' > 25.6 mag
i' > 24.8 mag
z' > 23.4 mag
J > 21.9 mag
H > 21.4 mag
K > 20.2 mag

Given limits are calibrated against Sky-Mapper and 2MASS field stars and are not
corrected for the Galactic foreground extinction corresponding to a reddening of
E_(B-V)= 0.01 in the direction of the burst (Schlafly & Finkbeiner 2011).
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