[vsnet-grb-info 17001] GRB150911A MITSuME Okayama Ks-band upper-limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18282
SUBJECT: GRB150911A MITSuME Okayama Ks-band upper-limit
DATE:    15/09/11 20:40:22 GMT
FROM:    Kenshi Yanagisawa at OAO/NAOJ  <yanagi at oao.nao.ac.jp>

Kenshi Yanagisawa, Daisuke Kuroda, Yasuhiro Shimizu, Hideyuki Izumiura
(OAO/NAOJ), Michitoshi Yoshida (Hiroshima-U), Kouji Ohta(Kyoto-U)
and Nobuyuki Kawai(Tokyo Tech.) report on behalf of the MITSuME
collaboration:

We observed the field of GRB150911A (Starling et al, GCN18280)
in Ks-band with a wide-field near infrared imager at Okayama
Astrophysical Observatory (Japan).  The imager has effective
aperture of 0.91 m.

Observations started from 18:56 UT on 11th September, just 16 min
after the BAT trigger, to 19:10 UT. The total exposure of 6 min
was successfully obtained.

In our co-add image, we did not find any new point source within
the enhanced XRT error circle (Starling et al, GCN18280) down
to limiting magnitude of Ks=14.3 (Vega, S/N=10) . The photometric
calibration was made against 2MASS field stars.

T0+[s]      MID-UT     T-EXP[sec]      Ks
---------------------------------------------------
 +1380      19:03          375        >14.3
---------------------------------------------------
T0+ : Elapsed time after the burt [sec]
T-EXP: Total Exposure time [sec]