TITLE:   GCN CIRCULAR
NUMBER:  20442
SUBJECT: GRB 161219B: afterglow and SN2016jca optical observations
DATE:    17/01/12 17:57:30 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), E. Mazaeva (IKI), R. Inasaridze (AbAO), A. Moskvitin (SAO 
RAS), E. Klunko (ISTP), V. Rumyantsev (CrAO), I. Korobtsev (ISTP),   V. 
Ayvazian  (AbAO),  O. Kvaratskhelia  (AbAO), G. Inasaridze (AbAO),  I. 
Molotov (KIAM), A. Pozanenko (IKI)    report on behalf of  larger GRB 
follow-up collaboration:

We observed the field of GRB 161219B (Swift trigger 727541; D'Ai,GCN 20296) 
with AZT-33IK (Mondy), ZTSh (CrAO), AS-32 (AbAO) and Zeiss-1000 (SAO RAS) 
telescopes.  We obtained  unfiltered images (AbAO) and images in R-filter 
(other observatories). The optical source associated with the afterglow 
(D'Ai et al., GCN 20296; Kruehler et al., GCN 20299; Guidorzi et al., GCN 
20300; Martin-Carrillo et al., GCN 20305) and SN2016jca  (de Ugarte Postigo 
et al., GCN 20342; Chen et al., GCN 20380) is clearly visible in all our 
observations.

Preliminary light curve of the afterglow and  SN2016jca  can be found at
http://grb.rssi.ru/GRB161219B/GRB161219B_LC.png
Photometry is based on nearby USNO-B1.0 stars (R2) common for all images. 
Late time photometry is contaminated by  Pan-STARRS galaxy previously 
reported by Kruehler et al. (GCN 20299), and  also presented in USNO-B1.0. 
Apparent maximum brightness of the SN2016jca was observed at about 11 days 
after burst onset (R = 19.2 at 2016-12-30 (UT) 20:04:59) and actual SN peak 
could be slighter later,  between 11 and 14 days after burst.