GCN Circular 20820
Subject
GRB 170306A: LCO Cerro Tololo observations
Date
2017-03-06T09:02:26Z (7 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc
(U. Nova Gorica), C.G. Mundell (U. Bath) on behalf of a large
collaboration report:
We observed Swift GRB 170306A (Markwardt et al. GCN 20819) on March 6,
07:26:06 UT (~20 minutes since the GRB trigger time) with the 1-m LCO
unit in Cerro Tololo with SDSS r and i filters. Within the Swift XRT
error circle we detect an uncatalogued source at the following position:
RA(J2000) = 17:32:16.76
Dec(J2000)= -44:44:53.7
with an error radius of 1". We find the following magnitude values as
calibrated against nearby USNOB-1 objects (R2 and I values):
Mid Time Exposure Filter Magnitude (AB)
(min) (s)
-------------------------------------------------------
24 5x60 SDSS-I 18.5 +- 0.2
34 5x60 SDSS-R 19.0 +- 0.2
-------------------------------------------------------
At the moment we cannot make any statement on the temporal behaviour of
the source. The expected Galactic dust extinction is A_r=1~mag, A_i=0.7
mag (from Schlafly et al. 2011). Given the crowded field, we caution
that the source might be unrelated to the GRB.