GW190814's secondary component with mass $(2.50-2.67)$ M$_{\odot}$ as a super-fast pulsar

TL;DR

This paper proposes that the secondary component of GW190814 could be a super-fast pulsar with a mass between 2.50 and 2.67 solar masses, potentially the fastest and most massive pulsar observed, supported by high-density nuclear physics constraints.

Contribution

It demonstrates, using the RNS code and causality surface EOS constraints, that such a massive, fast-spinning pulsar could exist within known physics limits.

Findings

Possible explanation for GW190814's secondary as a super-fast pulsar.

Supports pulsars heavier than 2.50 M$_{ ext{solar}}$} can spin faster than 971 Hz.

Large EOS parameter space allows for such massive, fast pulsars.

Abstract

Using Stergioulas's RNS code for investigating fast pulsars with Equation of States (EOSs) on the causality surface (where the speed of sound equals that of light) of the high-density EOS parameter space satisfying all known constraints from both nuclear physics and astrophysics, we show that one possible explanation for the GW190814's secondary component of mass $(2.50-2.67)$ M$_{\odot}$ is that it is a super-fast pulsar spinning faster than 971 Hz about 42\% below its Kepler frequency. If confirmed, it would be the fastest pulsar with the highest mass observed presently. There is a large and physically allowed EOS parameter space below the causality surface where pulsars heavier than 2.50 M$_{\odot}$ are supported if they can rotate even faster with critical frequencies depending strongly on the high-density behavior of nuclear symmetry energy.