Abstract:
S190426c/GW190426 152155 was the first probable neutron star–black hole merger candidate detected by the LIGO-Virgo
Collaboration. We undertook a tiled search for optical counterparts of this event using the 0.7-m GROWTH-India Telescope.
Over a period of two weeks, we obtained multiple observations over a 22.1 deg2 area, with a 17.5 per cent probability of containing
the source location. Initial efforts included obtaining photometry of sources reported by various groups, and a visual search for
sources in all galaxies contained in the region. Subsequently, we have developed an image subtraction and candidate vetting
pipeline with ∼ 94 per cent efficiency for transient detection. Processing the data with this pipeline, we find several transients,
but none that are compatible with kilonova models. We present the details of our observations, the working of our pipeline,
results from the search, and our interpretations of the non-detections that will work as a pathfinder during the O4 run of LVK.
