[vsnet-grb-info 23533] LIGO/Virgo S190901ap: GROWTH-India follow-up of ZTF19abvionh

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25632
SUBJECT: LIGO/Virgo S190901ap: GROWTH-India follow-up of ZTF19abvionh
DATE:    19/09/03 16:40:09 GMT
FROM:    Gaurav Waratkar at IIT Bombay  <gauravwaratkar24 at gmail.com>

Harsh Kumar (IITB), Anirban Dutta (IIA), Gaurav Waratkar (IITB), Kunal
Deshmukh (IITB), Maitreya Khandagale (IITB), Avinash Singh (IIA), Erik Kool
(OKC), Varun Bhalerao (IITB), G. C. Anupama (IIA), Urgain Stanzin (IIA)
report on behalf of the GROWTH collaboration:

We observed the optical counterpart candidate ZTF19abvionh (Erik Kool et
al. GCN 25616, M. J. B. Rosell et al. GCN 25622, GCN 25624) of the
gravitational
wave trigger S190901ap (LVC et al. GCN 25606, GCN 25614) with the 0.7m
GROWTH-India telescope. We obtained a series of exposures, each 600 sec
long, in SDSS-r filter starting from 2458729.15950926 JD. We used PS1
catalog images for image subtraction. The candidate was clearly detected in
the subtracted images. Photometry of the subtracted images is reported
below:

------------------------------------------------------------------

JD(Start) | Name | Filter | Mag | Mar_err|

------------------------------------------------------------------

2458729.15950926 | ZTF19abvionh | r | 20.81 | 0.117

2458729.16622148 | ZTF19abvionh | r | 20.83 | 0.088

2458729.20642199 | ZTF19abvionh | r | 20.56 | 0.108

2458729.21345010 | ZTF19abvionh | r | 20.50 | 0.088

------------------------------------------------------------------

Our measurements indicate a rise in the r-band brightness of the candidate.
Further observations are planned. We encourage further monitoring of this
candidate.


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).