[vsnet-grb-info 17312] GRB 151205C: Optical follow-up observations at Kiso

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18677
SUBJECT: GRB 151205C: Optical follow-up observations at Kiso
DATE:    15/12/10 03:00:06 GMT
FROM:    Masaomi Tanaka at NAOJ  <masaomi.tanaka at nao.ac.jp>

Yuki Kikuchi (U. of Tokyo), Masaomi Tanaka (NAOJ), Ryou Ohsawa,
Makoto Ichiki, Shigeyuki Sako, Tomoki Morokuma, Mamoru Doi (U. of Tokyo),
Nozomu Tominaga (Konan U.), Motoko Serino (RIKEN), Akihiro Suzuki,
Keiichi Maeda (Kyoto U.), and Takanori Sakamoto (AGU) report:

We performed optical non-filter imaging observations for
the MAXI-detected burst GRB 151205C (Nakajima et al. GCN Circ. 18666)
with a prototype model camera of Tomo-e Gozen (Tomo-e PM).
Tomo-e Gozen is a wide-field optical imaging camera
with 84 1kx2k CMOS sensors on the focal plane of
the 1.05-m Kiso Schmidt telescope (Sako et al. in preparation,
http://www.ioa.s.u-tokyo.ac.jp/tomoe/).
The prototype model camera has 8 CMOS sensors along the RA direction
with spatial gaps of 25 arcmin between the adjacent chips.
The field-of-view of each chip is 39.7 arcmin (RA) x 22.4 arcmin (Dec).
Thanks to the low dark current of the sensors in room
temperature, we operate the CMOS sensors without coolers
which enables us to make a light-weight camera system.
By using 1 of 8 chips of Tomo-e PM,
multiple regions which cover in total 95% of the localization area 
(with the following central coordinates) have been observed.

 RA       | Dec       | Obs. time        | t-t0*  | Exptime |
 (J2000)  | (J2000)   | (UT)             | (days) | (sec)   |
 22:00:34 | +77:39:51 | 2015 Dec 6 14:08 | 0.59   | 150     |
 21:58:01 | +77:41:46 | 2015 Dec 6 14:25 | 0.60   | 150     |
 22:05:23 | +78:26:45 | 2015 Dec 7 09:12 | 1.39   | 180     |
 22:02:51 | +78:06:14 | 2015 Dec 7 09:15 | 1.39   | 180     |
 21:55:36 | +77:28:11 | 2015 Dec 7 09:22 | 1.39   | 180     |
 21:58:37 | +77:45:37 | 2015 Dec 7 09:26 | 1.40   | 180     |
 22:08:11 | +78:19:44 | 2015 Dec 8 14:22 | 2.60   | 150     |
 22:04:56 | +78:03:18 | 2015 Dec 8 14:25 | 2.61   | 144     |
 22:02:25 | +77:42:13 | 2015 Dec 8 14:29 | 2.61   | 144     |
 21:58:14 | +77:22:13 | 2015 Dec 8 14:31 | 2.61   | 180     |
 21:55:13 | +77:04:13 | 2015 Dec 8 14:34 | 2.61   | 180     |
* time after the burst

We performed image subtraction using
PTF R-band data taken on 2011 Jul 17 as references
(obtained through IPAC, Law et al. 2009, PASP, 121, 1395;
Laher et al. 2014, PASP, 126, 674).
No new transient objects have been found within these fields.
The limiting magnitudes of our data are about 20 mag
(calibrated with USNO UCAC3 catalog, Zacharias et al. 2010, AJ, 139, 2184).