{
  "bibcode": "2019GCN.24193....1T",
  "body": "Han-Jie Tan (NCU), Po-Chieh Yu (NCU), Chow-Choong Ngeow (NCU), Wing-Huen Ip\n(NCU)\n\nOn behalf of Global Relay of Observatories Watching Transients Happen\n(GROWTH) collaborations\n\nWe report the photometric measurements of two promising candidates\nZTF19aarykkb and ZTF19aarzaod (GCN 24191) associated with the gravitational\nwave trigger S190425z (GCN 24168) using Lulin One-meter Telescope(LOT) in\nTaiwan. The observations were conducted using g, r, i filters at 2019-04-25\n15:57:19 UT, ~7.65 hours after the trigger, and 2019-04-25 17:25:43, ~9.12\nhours after the trigger, respectively. Preliminary photometry were obtained\nby calibrating with Pan-STARRS catalog.\n\nWe would like to thank the staff in Lulin Observatory for helping the\nobservations.\n\nSummary of ZTF19aarykkb:\n         UT                        Filter          Exp(s)\nMag (AB)\n2019-04-25 15:58:49           g           180                18.84+/-0.04\n2019-04-25 16:02:11           r             180                18.23+/-0.02\n2019-04-25 16:05:33           i             180                17.92+/-0.02\n\nSummary of ZTF19aarzaod:\n2019-04-25 17:48:24         g                300                21.45+/0.47\n2019-04-25 17:53:45         r                 300\n 20.26+/-0.25\n2019-04-25 17:41:56         i                 300\n 19.93+/-0.13\n\nAlso, we searched for optical counterpart in 90% localization area of\nLIGO/Virgo S190425z (GCN 24168). The observation started at 2019-04-25\n12:27:23 UT, 249 minutes after the trigger, and 27 galaxies were observed\nin R-band with 180 second exposure time. No obvious transient can be\nidentified brighter than R~20 mag (AB). The galaxy coordinates are listed\nbelow.\n\nRA(deg)   DEC(deg)\n194.9152    +53.341\n212.0897    +55.302\n212.6985    +35.913\n213.2136    +35.711\n213.6132    +36.404\n216.0865    +36.461\n217.9843    +33.643\n218.3270    +34.735\n219.1718    +34.973\n232.4191    +30.486\n235.3749    +27.986\n236.0957    +25.327\n236.3709    +26.603\n236.9752    +25.729\n239.0161    +24.448\n239.2193    +24.662\n239.2199    +25.569\n239.6450    +27.618\n239.7168    +26.136\n239.9651    +25.941\n241.1394    +23.838\n241.2978    +24.960\n242.2803    +21.868\n242.7183    +22.626\n242.8088    +26.923\n242.8782    +23.812\n243.0847    +23.002",
  "circularId": 24193,
  "createdOn": 1556222103000,
  "email": "mansikasliwal@gmail.com",
  "subject": "LIGO/Virgo S190425z: Lulin Follow-Up Observations",
  "submitter": "Mansi M. Kasliwal at Caltech/Carnegie  <mansikasliwal@gmail.com>",
  "eventId": "LIGO/Virgo S190425z"
}