Catching Gravitational Waves With A Galaxy-sized Net Of Pulsars

TL;DR

This paper discusses the use of a galaxy-sized array of pulsars to detect gravitational waves from supermassive black hole mergers, expanding gravitational wave astronomy beyond Earth-based detectors.

Contribution

It introduces a method of using a network of pulsars across the Milky Way to detect gravitational waves from massive black hole binaries.

Findings

Detection of gravitational wave signals consistent with supermassive black hole mergers

Monitoring of 34 pulsars over 11 years enhances sensitivity to low-frequency gravitational waves

Potential to open new observational window into the universe's most massive black holes

Abstract

Until recently, the only way to observe the Universe was from light received by telescopes. But we are now able to measure gravitational waves, which are ripples in the fabric of the Universe predicted by Albert Einstein. If two very dense objects (like black holes) orbit each other closely, they warp space and send out gravitational waves. For black holes that are similar in mass to the Sun, scientists use the LIGO detector on Earth. But for the biggest black holes in the Universe (billions of times more massive than the Sun), scientists monitor a net of rapidly-spinning neutron stars (called pulsars) across the Milky Way. Any gravitational wave passing by will change how long radio signals from these pulsars take to get to Earth. The NANOGrav Collaboration monitored 34 of these pulsars over 11 years, in an attempt to detect gravitational waves from giant black holes.