GCN Circular 21145
Subject
GRB 170524A: TSHAO and CrAO optical observations
Date
2017-05-25T20:28:02Z (7 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), S. Nazarov (CrAO), A. Kusakin (Fesenkov Astrophysical
Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:
We observed the field of the Swift GRB 170524A (trigger=754322) (Gropp
et al., GCN 21135) with Zeiss-1000 (East) of Tien Shan Astronomical
Observatory and AZT-8 telescope of CrAO. We obtained several images in R
filter. The TSHAO observations started on 2017-05-24 (UT) 20:31:45 under
not optimal weather conditions. Observations in CrAO started on
2017-05-25 (UT) 00:18:50. Within enhanced XRT position (Evans et al. GCN
21136) we did not detect any optical source in the first epoch. In the
second epoch (CrAO observation) we detected an object which is on the
edge of the enhanced XRT position. The object has coordinates (J2000)
21:17:56.30 +48:36:27.9 with uncertainties of about 1 arcsec in each
coordinate and brightness of R=20.10 +/- 0.15 at 0.1992 days after the
Swift trigger. For now we can not say anything about the object
variability. However the object is barely visible in DSS2 (Red).
The preliminary results of field photometry are as follows
Date UT start t-T0 Filter Exp. UL(3 sigma)
(mid, days) (s)
2017-05-24 20:31:45 0.06857 R 46*120 20.3
2017-05-25 00:18:50 0.19920 R 10*180 21.5
Photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1386-0392957 16.69
1385-0394718 17.29
1386-0392907 17.11
The finding chart of the object can be found at
http://grb.rssi.ru/GRB170524A/GRB170524A_CrAO_170524.png
