[vsnet-grb-info 20367] GRB 180305A: Mondy optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22463
SUBJECT: GRB 180305A: Mondy optical observations
DATE:    18/03/06 17:07:13 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI),  A. Pozanenko (IKI),  E. Klunko (ISTP),  A. Volnova 
(IKI) report on behalf of of larger GRB follow-up collaboration:

We observed the field of LAT/Fermi GRB 180305A (Axelsson, et al., GCN 
22457) and Konus-Wind (Svinkin et al., GC 22461) with AZT-33IK telescope 
of Sayan observatory (Mondy).  We obtained several images in R-filter 
starting on Mar. 06 (UT) 12:35:17.  The afterglow candidate  (Troja  et 
al., GCN 22460) is clearly detected within XRT/Swift error circle 
(D'Avanzo et al., GCN 22462). Preliminary photometry is following.

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


2018-03-06  12:35:17  1.15219    R     30*120 22.69   0.15  23.7

The photometry is based on nearby USNO-B1.0 stars
USNO-B1_id   R2

1221-0050419 18.60

1221-0050432 16.39

1221-0050407 19.31


Since the source has faded in comparison with the previous observation 
(Troja  et al., GCN 22460) we can confirm the afterglow of GRB 180305A.