GCN Circular 24201
Subject
LIGO/Virgo S190425z - GROWTH-India follow-up of two ZTF candidates
Date
2019-04-26T00:20:56Z (5 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
V. Bhalerao, H. Kumar, V. Karambelkar, G. Waratkar, Y. Sharma (IITB), G. C. Anupama (IIA) report on behalf of the GROWTH collaboration:
We observed the two most promising candidates reported by the Zwicky Transient Facility (Kasliwal et al., GCN 24191) for the follow up the GW candidate S190425z (GCN 24168) with the GROWTH-India telescope. We obtained multiple images in g, r, and i bands, with exposures ranging from 300 sec - 600 sec. Source photometry for ZTF19aarykkb is given below.
Date-Time MJD exptime Filter Magnitude Magerr
2019-04-25 18:25:39 2458599.268 600 r 17.78 0.06
2019-04-25 18:06:40 2458599.255 600 r 17.82 0.08
2019-04-25 21:54:37 2458599.413 300 g 18.49 0.05
2019-04-25 22:01:34 2458599.418 300 g 18.46 0.05
2019-04-25 22:08:50 2458599.423 300 r 17.48 0.05
2019-04-25 22:40:29 2458599.445 600 i 16.99 0.04
2019-04-25 22:54:42 2458599.455 600 g 18.62 0.04
2019-04-25 23:06:41 2458599.463 600 g 18.36 0.17
We also observed ZTF19aarzaod multiple times with 3 exposures in g band, 4 r and 2 i band exposures respectively, each with an exposure time of 600 seconds. We see a weak source in the r and i band images, further analysis is underway. The source appears to be fading rapidly in all bands.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7 degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).