[vsnet-grb-info 23844] LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25943
SUBJECT: LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
DATE:    19/10/04 16:31:19 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI),  A. Pozanenko (IKI),  V. Rumyantsev (CrAO), S. Belkin 
(IKI), A. Volnova (IKI)  report on behalf of larger GRB follow-up 
collaboration:

We observed the ZTF19acbpqlh (AT2019rpn) reported by Stein et al. (GCN 
25899) and the ATLAS19wyn (AT2019rpj) optical transients with ZTSh 2.6m 
telescope of CrAO observatory on Oct. 02 and Oct. 3.

Preliminary photometry of the optical transients   is following
(we repeat our photometry previously published in GCN 25928 in the table 
below for convenience)

Name,     UT start             T_mid Filter  Exp.     OT    err
                                (MJD)         (s)

AT2019rpj 2019-10-01 20:16:16  58757.84880 R 11*60   19.37   0.04
AT2019rpj 2019-10-01 20:28:33  58757.85886 B 15*60   19.86   0.04
AT2019rpj 2019-10-02 19:44:58  58758.82668 R 10*60   19.31   0.05
AT2019rpj 2019-10-02 20:28:33  58758.83825 B 20*60   19.83   0.03
AT2019rpj 2019-10-03 17:56:18  58759.75245 R 12*60   19.33   0.06
AT2019rpj 2019-10-03 18:11:03  58759.76604 B 22*60   19.91   0.06

AT2019rpn 2019-10-01 19:30:53  58757.81861 R 12*60   19.26   0.11
AT2019rpn 2019-10-01 19:47:03  58757.83270 B 11*60   20.17   0.07
AT2019rpn 2019-10-02 19:01:22  58758.79640 R 10*60   19.34   0.12
AT2019rpn 2019-10-02 19:12:33  58758.80874 B 22*60   20.20   0.04
AT2019rpn 2019-10-03 17:13:26  58759.72220 R 10*60   19.26   0.12
AT2019rpn 2019-10-03 17:26:42  58759.73485 B 21*60   20.18   0.05

The photometry is based on the same stars reported by Mazaeva et al. 
(GCN 25928).

The color of AT2019rpj (B-R)  = 0.5 is not resemble of any object which 
can be related to LVC OT counterpart, and the detection the AT2019rpj 
before S190930t (Smartt et al. GCN 25922),  exclude it from candidates.
Based on the photometry, it can be seen that AT2019rpn does not rise for 
three epochs (which is previously reported by Tan et al. (GCN 25916)) or 
is near a maximum.