Understanding gravity using a COMprehensive search for fast-spinning Pulsars And CompacT binaries

Introduction

The description of gravity by Einstein's theory of general relativity has passed all its experimental tests with flying colours, including the recent groundbreaking direct detection of gravitational waves. However, there still remain some glaring shortcomings, ranging from its irreconcilability with quantum mechanics to the dark energy that accelerates the expansion of our Universe.

Alternative Theories

There are also several alternative theories that contend to be the best descriptor of gravity. Hence, it is imperative to find new laboratories to test these theories and further our understanding of gravity.

The Role of Pulsars

This is where pulsars, a special type of star, prove useful. Pulsars are remarkable laboratories in space. Observations of pulsars at radio wavelengths provide rare opportunities to understand how gravity works near strongly self-gravitating bodies and provide clues on the state of matter at supra-nuclear densities.

This provides important complementary knowledge to our understanding of gravity and nuclear physics compared to other experiments such as ground-based gravitational wave detectors.

The COMPACT Project

COMPACT is an ambitious project that aims to discover some of the most extreme classes of pulsar laboratories. The project will perform Petabyte-scale data acquisition and processing to search for two specific kinds of pulsars:

1. Relativistic binary pulsars with orbital periods of just a few minutes to a few hours around other neutron stars, white dwarfs, or black holes.
2. Pulsars with extremely fast spin periods of the order of a millisecond or less.

Even a single discovery of either class of pulsars has the potential to fundamentally change (or solidify) a huge range of poorly known physics, from the internal composition of neutron stars to how they evolve in binaries, and our understanding of the effects of strongly gravitating bodies on the space-time in their vicinity.

Implications for Gravitational Wave Astronomy

The survey also has immediate and profound implications for gravitational wave astronomy across multiple wavelengths.