[vsnet-grb-info 25644] GRB 200514A: MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27744
SUBJECT: GRB 200514A: MITSuME Akeno optical upper limits
DATE:    20/05/15 15:35:39 GMT
FROM:    Adachi Ryo at Tokyo Institute of Tech  <adachi at hp.phys.titech.ac.jp>

N. Nakamura, R. Hosokawa, R. Adachi, K. L. Murata, M. Niwano, F.
Ogawa, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the
MITSuME collaboration:

We performed tiling observation for the MAXI/GSC error region of GRB
200514A (Y. Okamoto et al., GCN Circular #27735; Ricciarini et al.,
GCN Circular #27743) with an optical tri-color (g', Rc, and Ic) camera
attached to the MITSuME 50cm telescopes at Akeno Observatory in Japan.

The follow up observation started at 2020-05-14 10:36:15 UT, 495
minutes after the trigger.

Our tiling observation covered almost ~65% of the MAXI/GSC error
region (GCN Circular #27735). Compared our co-added images with the
GSC2.3 and UCAC4 catalogs, we found no bright optical transient in the
observed region except a high proper motion star (R.A.=11:20:26.73,
Dec.=+19:53:14) listed in the NEOWISE/AllWISE high proper motion
objects (Schneider et al. 2016). Because the elevation of the target
field had dropped from 75 deg to 16 deg during the observations and
the sky condition was unstable, the obtained upper limits are
different for each field. The 5-sigma upper limits of the co-added
images are listed below.

Field num. | center position(R.A., Dec.) | size of field(R.A.(arcmin)
x Dec.(arcmin)) | 5-sigma upper limit | MID-UT(UT) | exposure
time(sec)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Field 0 | 11:21:03, +19:43:24 | 24.9 x 25.9 | g' > 18.4, Rc > 18.2, Ic
> 16.5 | 12:24:50 14 May | 870
Field 1 | 11:19:53, +19:52:19 | 25.6 x 26.1 | g' > 18.0, Rc > 17.7, Ic
> 16.9 | 12:35:31 14 May | 480
Field 2 | 11:20:25, +19:26:36 | 25.8 x 25.9 | g' > 16.8, Rc > 16.7, Ic
> 16.1 | 12:44:04 14 May | 1170
Field 3 | 11:19:15, +19:35:00 | 25.7 x 26.0 | g' > 18.3, Rc > 17.9, Ic
> 17.1 | 12:05:44 14 May | 660
Field 4 | 11:21:41, +19:59:30 | 25.6 x 26.1 | g' > 17.8, Rc > 17.6, Ic
> 16.7 | 11:18:32 14 May | 360
Field 5 | 11:20:30, +20:08:15 | 25.6 x 25.9 | g' > 18.0, Rc > 17.4, Ic
> 16.8 | 12:33:09 14 May | 570
Field 6 | 11:19:49, +19:09:39 | 25.7 x 25.9 | g' > 18.7, Rc > 18.3, Ic
> 17.5 | 12:11:34 14 May | 660
Field 7 | 11:18:42, +19:18:54 | 25.7 x 26.1 | g' > 18.0, Rc > 17.6, Ic
> 16.8 | 11:26:50 14 May | 210
Field 8 | 11:21:55, +20:24:47 | 25.9 x 26.0 | g' > 17.1, Rc > 17.0, Ic
> 15.9 | 16:21:30 14 May | 150
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
We used the UCAC4 catalog for the flux calibration. The magnitudes are
expressed in the AB system. The images were processed in real-time
through the MITSuME GPU reduction pipeline (Niwano et al., in prep;
https://github.com/MNiwano/Eclair).