Speaker
Description
Coalescence of close pairs of relativistic objects like black holes
and neutron stars provides
extremely valuable information on the evolution of stars, galaxies and
the Universe as a whole.
These events are observed in the gravitational-wave and (less
frequently) in the electromagnetic ranges.
Electromagnetic events (gamma-ray bursts and kilonovae) are explained
in the literature in two different scenarios:
the fusion of two neutron stars, or the stripping of a neutron star by
its more massive companion.
A stellar-mass black hole may also be such a companion.
The report will briefly describe the achievements and problems in
explaining signals from pairs of relativistic
objects in different scenarios.
The LIGO, VIRGO, and KAGRA detectors are already routinely detecting
gravitational waves from black hole mergers.
There are much fewer signals from binary neutron stars.
To detect them against the noisy background, the task of quickly
calculating patterns (templates) for gravitational
waves from coalescing objects is very relevant.
In different scenarios (merging vs stripping), different gravitational
wave forms are predicted.
We show that the authors who did the "fully analytical" template calculations
in various orders of post-Newtonian decomposition, have actually
solved numerically the differential equations arising in the problem .
In our work with I.Klopova-Saporovskaya and A.Mishakina, we explore
the limits to which truly fully analytical solutions can be obtained, which is useful for quickly detecting a signal in gravitational waves using the matched
filtering method at the earliest stages.
