[vsnet-grb-info 20344] MAXI J1813-095 source: AbAO optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22440
SUBJECT: MAXI J1813-095 source: AbAO optical observations
DATE:    18/02/24 12:35:09 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

We observed the field of the MAXI J1813-095 source (trigger=811167; ATel 
#11323 Kawase et al.) with AS-32 (0.7m). We obtained several unfiltered 
images  starting on Feb. 22 (UT) 01:40:27. We do not detect any evident 
object within XRT error circle (Beardmore  et al., GCN 22431). The only 
one object which is visible in POSS2 in coordinates  (J2000) 18:13:33.84 
  -09:31:54.5 +/-0.8 is also visible in our combined image. The 
magnitude of the source is 18.92 +/- 0.12 and calibrated against nearby 
USNO-B1.0 stars.

The field photometry is following

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

2018-02-22  01:40:27  0.08079   CR    25*60     n/d   n/d  20.2

The photometry is based on several USNO-B1.0 stars
USNO-B.1_id     R2
0804-0407386    15.99
0804-0407400    16.34
0804-0407451    15.77