[vsnet-grb-info 23127] LIGO/Virgo S190728q: MITSuME Okayama and Bisei Follow-Up of ZTF19abjethn (AT2019lvs)

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25226
SUBJECT: LIGO/Virgo S190728q: MITSuME Okayama and Bisei Follow-Up of ZTF19abjethn (AT2019lvs)
DATE:    19/07/31 02:16:30 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata at u.phys.nagoya-u.ac.jp>

Y. Yatsu, N. Kawai, K. L. Murata, R. Adachi, K. Iida, M. Oeda, K.
Shiraishi, M. Niwano, F. Ogawa, S. Toma and R. Hosokawa (Tokyo Tech), R.
Itoh (Bisei Astronomical Observatory) report on behalf of the MITSuME
collaboration:

We observed the ZTF optical transient ZTF19abjethn (AT2019lvs) listed in
Kasliwal et al. (GCN 25199) using the optical three color (g’, Rc, and Ic)
CCD cameras attached to the MITSuME 50 cm telescope of Okayama
Astrophysical Observatory, and using the CCD camera with V, R, and I band
filters attached to the 101cm telescope of Bisei Astronomical Observatory.

The observation of the MITSuME and the Bisei telescopes started on
2019-07-28 13:29:47 UT and 2019-07-28 15:27:39 UT, respectively. The
measured magnitudes are listed as follows.

| telescope | MID-UT  | T-EXP [sec] | magnitudes |
-----------------------------------------------------------------------------------------------
| MITSuME Okayama 50cm | 15:09:47  | 10260 | g’ = 17.40 +/- 0.07 Rc = 17.70
+/- 0.06  Ic = 17.53 +/- 0.06 |
| Bisei 101 cm | 15:55:09 | 600 | V = 17.23 +/- 0.02 |
| Bisei 101 cm | 15:37:27 | 1200 | R = 17.41 +/- 0.02 |
| Bisei 101 cm | 16:08:21 | 600 | I = 17.40 +/- 0.04 |
---------------------------------------------------------------------------------------------------
T-EXP: Total Exposure time
We used PS1 catalog for flux calibration.
The magnitudes are expressed in the AB system.
The color terms are not used in the above magnitudes.

There are non-negligible differences in the magnitudes between MITSuME and
Bisei, which might be explained by their color-terms.

This observation was carried out by the Global Relay of Observatories
Watching Transients Happen (GROWTH) collaboration.