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GCN Circular 24193

Subject
LIGO/Virgo S190425z: Lulin Follow-Up Observations
Date
2019-04-25T19:55:03Z (5 years ago)
From
Mansi M. Kasliwal at Caltech/Carnegie <mansikasliwal@gmail.com>
Han-Jie Tan (NCU), Po-Chieh Yu (NCU), Chow-Choong Ngeow (NCU), Wing-Huen Ip
(NCU)

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

We report the photometric measurements of two promising candidates
ZTF19aarykkb and ZTF19aarzaod (GCN 24191Not found
 
 
) associated with the gravitational
wave trigger S190425z (GCN 24168Not found
 
 
) using Lulin One-meter Telescope(LOT) in
Taiwan. The observations were conducted using g, r, i filters at 2019-04-25
15:57:19 UT, ~7.65 hours after the trigger, and 2019-04-25 17:25:43, ~9.12
hours after the trigger, respectively. Preliminary photometry were obtained
by calibrating with Pan-STARRS catalog.

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

Summary of ZTF19aarykkb:
         UT                        Filter          Exp(s)
Mag (AB)
2019-04-25 15:58:49           g           180                18.84+/-0.04
2019-04-25 16:02:11           r             180                18.23+/-0.02
2019-04-25 16:05:33           i             180                17.92+/-0.02

Summary of ZTF19aarzaod:
2019-04-25 17:48:24         g                300                21.45+/0.47
2019-04-25 17:53:45         r                 300
 20.26+/-0.25
2019-04-25 17:41:56         i                 300
 19.93+/-0.13

Also, we searched for optical counterpart in 90% localization area of
LIGO/Virgo S190425z (GCN 24168Not found
 
 
). The observation started at 2019-04-25
12:27:23 UT, 249 minutes after the trigger, and 27 galaxies were observed
in R-band with 180 second exposure time. No obvious transient can be
identified brighter than R~20 mag (AB). The galaxy coordinates are listed
below.

RA(deg)   DEC(deg)
194.9152    +53.341
212.0897    +55.302
212.6985    +35.913
213.2136    +35.711
213.6132    +36.404
216.0865    +36.461
217.9843    +33.643
218.3270    +34.735
219.1718    +34.973
232.4191    +30.486
235.3749    +27.986
236.0957    +25.327
236.3709    +26.603
236.9752    +25.729
239.0161    +24.448
239.2193    +24.662
239.2199    +25.569
239.6450    +27.618
239.7168    +26.136
239.9651    +25.941
241.1394    +23.838
241.2978    +24.960
242.2803    +21.868
242.7183    +22.626
242.8088    +26.923
242.8782    +23.812
243.0847    +23.002