TITLE:   GCN CIRCULAR
NUMBER:  6945
SUBJECT: GRB071010b: optical observations
DATE:    07/10/19 19:41:37 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Klunko, A. Marchenkov, M. Eselevich (ISTP),  A. Shulga, A. Volnova (SAI 
MSU),  A. Pozanenko (IKI)  on behalf of larger GRB follow up collaboration 
report:

We observed the optical afterglow (Oksanen GCN 6873, Kann et al. GCN 6884) 
of  GRB071010b  (Markwardt  et al., GCN 6871) in R-band on Oct.12 ((UT) 
19:44:42 - 20:45:06) and Oct. 13 ((UT)19:17:13 - 20:14:49) with 1.5m 
telescope of Sayan observatory. The optical afterglow is clearly visible in 
stacked images of  both epochs. Based on two USNO B1.0 stars  (Kann et. al 
GCN 6918) (RA (J2000) = 10:02:09.93, Dec. (J2000) = +45:41:18.4, R2=16.80; 
RA (J2000) = 10:02:23.11, Dec. (J2000) = +45:41:41.1, R2=16.94)  we 
estimated brightness of  the optical afterglow:

T0+  ,        Exposure,   R_mag
(mid time)

1.9995 d   15x240 s     20.5 +/-0.1
2.979 d     20x180 s     20.8 +/-0.2

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