[vsnet-grb-info 25029] GRB 200216B: second epoch optical upper limit at Mondy observatory

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27128
SUBJECT: GRB 200216B: second epoch optical upper limit at Mondy observatory
DATE:    20/02/19 12:01:00 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), E. Mazaeva (IKI), 
A. Volnova (IKI) report on behalf of IKI-GRB-FuN:

We observed the field of GRB 200216B (D'Avanzo et al., GCN 27102: Fermi 
GBM team, GCN 27101) with AZT-33IK telescope of Sayan observatory 
(Mondy) starting on Feb. 18 (UT) 16:02:31. We did not detect any object 
in the enhanced Swift-XRT position (Goad et al., GCN 27106). In 
particular we do not detect possible IR-counterpart (Levan et al., GCN 
27114). Upper limit is 22.8R.

We detected the object reported earlier (Pozanenko et al., GCN 27122) 
with coordinates (J2000) 10:41:44.54 +19:28:19.3  which is 14.5 arcsec 
apart from center of enhanced XRT error circle (Goad et al., GCN 27106). 
  Preliminary photometry of the object is following:

Date       UT start   t-T0       Filter Exp.    OT   Err.    UL(3sigma)
                        (mid, days)             (s)

2020-02-18 16:02:31   2.12497     R     30*120   22.7 0.3    22.8


Power law index of a light curve of the object calculated between the 
two epochs is about -0.3. Therefore the object might not be related to 
GRB 200216B.