This book provides a concise introduction to the physics of gravitational waves. It is aimed at graduate-level students and PhD scholars.

Ever since the discovery of gravitational waves in 2016, gravitational wave astronomy has been adding to our understanding of the universe.

Gravitational waves have been detected in the past few years from several transient events such as merging stellar-mass black holes, binary neutron stars, etc. These waves have frequencies in a band ranging from a few hundred hertz to around a kilohertz to which LIGO type instruments are sensitive. LISA will be sensitive to much lower range of frequencies from SMBH mergers. Apart from these cataclysmic burst events, there are innumerable sources of radiation which are continuously emitting gravitational waves of all frequencies. These include a whole mass range of compact binary and isolated compact objects and close planetary stellar entities. This book discusses the gravitational wave background produced in typical frequency ranges from such sources emitting over a Hubble time and the fluctuations in the h values measured in the usual devices. Also discussed are the high-frequency thermal background gravitational radiation from hot stellar interiors and newly formed compact objects.

The reader will also learn how gravitational waves provide a testing tool for various theories of gravity, i.e. general relativity and extended theories of gravity, and will be the definitive test for general relativity.

Autorentext

Arun Kenath is an avid physicist and academician whose primary area of expertise is cosmology and theoretical astrophysics. He has been an invited speaker to various institutions on topics ranging from cosmology to artificial intelligence. He has worked on the theoretical framework of gravitational waves and published multiple papers on this topic. Apart from research, he is also a keen populariser of physics and astronomy. His astronomy outreach include the editorship of 'Astrobiology Newsletter' and 'Astronomy and Astrophysics Newsletter'. He was also part of an international team of astrophysicists that organised an IAU sanctioned public outreach, "Astronomy during the pandemic", an online lecture series.

C Sivaram is a retired senior professor from Indian Institute of Astrophysics, Bangalore. He has been an invited speaker across the globe with multiple collaborations, including with Nobel laurettes. He had also made several contributions to high energy astrophysics, including origin and acceleration of the highest energy cosmic rays, gamma ray and neutrino production. He has also contributed to deeper understanding of dark matter and dark energy, black hole physics, and gravitational waves. He is also a popular science writer with scores of articles on various aspects of physics, astronomy, biology, and environment. He is also the editor in chief of 'Astrobiology Newsletter' and 'Astronomy and Astrophysics Newsletter'.