Time-domain Astronomy with Gravitational Waves

The two detectors of the Laser Interferometer Gravitational-wave Observatory (LI
GO) are set to begin their first observation
run later this year following hardware upgrades during the past few
years. A few other detectors in the world,
possibly including one in India, called LIGO-India, are expected to
join them in the coming years to usher in the
era of gravitational wave (GW) astronomy. Such a multi-baseline
network will be able to localize GW transients,
e.g., the merger of neutron star binaries, that it detects to within a
few to tens of square-degrees.
This presents both an opportunity and a challenge to other
observatories that are in pursuit of their
electromagnetic (EM) and particle counterparts, e.g., in the form of afterglows.
The opportunity is to develop a more complete understanding of these
sources. To wit, are short duration gamma-ray bursts
and kilonovae indeed associated with the merger of binaries involving
neutron stars? On the other hand,
the challenge is to be able to scan the large error boxes in the sky
of GW networks in an ingenious
way so as not to miss observing an EM counterpart.
After describing the general aspects of what is clearly a
multi-messenger endeavour,
I will also discuss how Indian telescopes can contribute to this effort.