GCN Circular 30246
Subject
GRB 210610A: Swift/UVOT Detection
Event
Date
2021-06-17T13:36:23Z (5 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU), M. Baer (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210610A
94 s after the BAT trigger (Page et al., GCN Circ. 30160). A fading source consistent
with the XRT position (Goad et al. GCN Circ. 30165) and the previously reported
optical counterpart (Hosokawa et al., GCN. Circ. 30161; Xu et al., GCN. Circ. 30162;
Kumar et al., GCN Circ. 30163; Lipunov et al., GCN. 30166; de Wet et al. GCN Circ.
30168; Horiuchi et al., GCN Circ. 30169; Youdong et al., GCN Circ. 30185; Watson et
al. GCN Circ. 30191) is detected in the initial UVOT exposures. The lack of detection
in the NUV filters for this bright counterpart is consistent with the redshift of 3.5
reported by Zhu et al. (GCN Circ. 30164) and Dutta et al. (GCN Circ. 30200).
The preliminary UVOT position is:
RA (J2000) = 13:37:07.59 = 204.28161 (deg.)
Dec (J2000) = +14:27:55.0 = 14.46527 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 94 244 147 17.09+/-0.03
white 587 892 68 17.92+/-0.07
v 636 829 38 16.74+/-0.14
v 4299 4498 196 >18.92
b 562 754 38 17.69+/-0.12
b 16163 17070 885 20.57+/-0.23
b 23125 45112 1552 >21.16
u 307 557 245 >20.02
uvw1 685 4908 216 >19.37
uvm2 4503 4703 196 >19.16
uvw2 4094 4294 196 >19.10
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.032 in the direction of the burst
(Schlegel et al. 1998).