TITLE:   GCN CIRCULAR
NUMBER:  19065
SUBJECT: GRB 160223B: Khureltogot optical observations
DATE:    16/02/24 01:31:17 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), S. Schmalz (ISON), A. Volnova (IKI),  N. Tungalag 
(Research Center of Astronomy and Geophysics MAS),   I. Molotov (KIAM),
 A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of INTEGRAL and Fermi GRB 160223B GRB 160223B (Gotz et 
al. GCN 19059; von Kienlin et al., GCN 19061) with ORI-40 telescope of 
Khureltogot observatory starting on Feb., 23 (UT) 12:34:31.  Within 2.2 
arcmin error circle of the GRB 160223B localization  (Gotz   et al., GCN 
19059) we marginally detect two possible sources not presented in USNO-B1.0 
catalog. Coordinates of the sources are

Source (1): (J2000) 6:20:05.53 +33:24:58.7
Source (2): (J2000) 6:20:03.89 +33:23:14.2

with uncertainties of 1 arcsec in both coordinates.
At this time we cannot confirm the sources are real  or variable due to low 
S/N and absence of a full dataset.

Preliminary photometry of the sources is following


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

2016-02-23 12:34:31  0.14969 none  7200   18.7 0.35  18.9  (1)
2016-02-23 12:34:31  0.14969 none  7200   18.7 0.30  18.9  (2)

Photometry is based on nearby USNO-B1.0  stars, R2 magnitudes:
USNO-B1_id        R2
1234-0146334    14.41
1234-0146221    14.55
1233-0156534    14.77
1234-0146470    13.48
1234-0146172    13.37