GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
Abstract
We observed the field of GRB 200228B (Laha et al., GCN 27254; Fermi GBM Team, GCN 27253) with AZT-33IK 1.5-m telescope of Sayan observatory (Mondy) starting on Feb. 28 (UT) 19:24:43. We detected an optical object near the enhanced XRT position of the XRT afterglow (Evans et al., GCN 27256). The object is absent in the Pan-STARRS DR1 catalog. The coordinates of the object are (J2000) 16:48:10.88 +16:59:04.5 with uncertainty of 0.5 arcsec in both coordinates. Next we observed the filed with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on Feb. 28 (UT) 23:08:56, Abastumani starting on Feb. 29 (UT) 01:38:45, Tien Shan Astronomical Observatory starting on Feb. 29 (UT) 23:08:56, and CrAO starting on Mar. 01 (UT) 00:58:28. Preliminary photometry of the object and the field is following. Date UT start t-T0 Filter Exp. OT Err UL(3sigma) telescope (mid, days) (s) 2020-02-28 19:24:43 0.351 R 15*120 21.8 0.3 21.7 AZT-33IK 2020-02-28 23:08:56 0.516 R 3480 n/d n/d 22.3 Z-1000 2020-02-29 01:38:45 0.616 R 46*60 n/d n/d 21.8 AS-32 2020-02-29 22:22:37 n/a R 5040 n/a n/a n/a Z-1000 2020-03-01 00:58:28 1.594 R 31*120 22.05 0.09 23.8 ZTSh Photometry is based on the USNO-B2.0 nearby stars. USNO-B1.0 R2 1069-0297786 18.42 1069-0297719 18.25 1069-0297797 14.78 The finding chart is available at http://193.232.11.154/GRB200228B/GRB200228B_AZT33IK_Z1000_ZTSh_FC.png (or http://grb.iki.rssi.ru/GRB200228B/GRB200228B_AZT33IK_Z1000_ZTSh_FC.png ). We suggest this object is a candidate in the afterglow of GRB 200228B after at least two epoch detections (see above), possible variability and absence of the bright object (R ~ 22) in the Pan-STARRS DR1. We did not detect any object at the position of NIR- candidate (Perley and Cockeram, GCN 27271).
- Publication:
-
GRB Coordinates Network
- Pub Date:
- March 2020
- Bibcode:
- 2020GCN.27276....1P