TITLE:   GCN CIRCULAR
NUMBER:  25916
SUBJECT: LIGO/Virgo S190930t: Lulin Follow-up Observations of AT2019rpn and AT2019rpj
DATE:    19/10/01 23:55:00 GMT
FROM:    Albert Kong at NTHU  <akhkong@gmail.com>

Han-Jie Tan (NCU), Albert Kong (NTHU), Chow-Choong Ngeow (NCU),
Wing-Huen Ip (NCU)

On behalf of the Global Relay of Observatories Watching Transients
Happen (GROWTH) collaborations

We report the photometric measurements of two optical counterpart
candidates ZTF19acbpqlh (AT2019rpn) and ATLAS19wyn/ZTF19acbpsuf
(AT2019rpj) associated with the gravitational wave event S190930t (GCN
#25876, #25899) using the Lulin One-meter Telescope (LOT) in Taiwan.
The observations were conducted using g, r, i filters starting at
2019-10-01 14:12:14 UT. Preliminary photometry was obtained by
calibrating with the Pan-STARRS catalog.

Summary of ZTF19acbpqlh:
UT                              Filter    Exp(s)      Mag (AB)
2019-10-01 14:14:56    g        300         20.80+/-0.25
2019-10-01 14:20:16    r         300         20.67+/-0.33
2019-10-01 14:25:36    i         300         20.80+/-0.39

Summary of ATLAS19wyn/ZTF19acbpsuf:
2019-10-01 14:31:53    g        300        19.65+/-0.08
2019-10-01 14:37:14    r         300        19.58+/-0.09
2019-10-01 14:42:35    i         300         19.55+/-0.12

We would like to thank the staff in Lulin Observatory for helping the
observations.