Gravitational waves from pulsars in the context of magnetic ellipticity

TL;DR

This paper estimates gravitational wave emissions from all known pulsars considering magnetic ellipticity, concluding that detection prospects with current and planned detectors are very low due to weak signals.

Contribution

It extends previous studies to all known pulsars using observable data and fiducial parameters to estimate gravitational wave amplitudes from magnetic ellipticity.

Findings

Maximum gravitational wave amplitude estimated at ~10^{-28}

Detection prospects are pessimistic with current and future detectors

Magnetic ellipticity likely produces signals too weak for detection

Abstract

In one of our previous articles we have considered the role of a time dependent magnetic ellipticity on pulsars' braking indices and on the putative gravitational waves these objects can emit. Since only nine of more than 2000 known pulsars have accurately measured braking indices, it is of interest to extend this study to all known pulsars, in particular to what concerns the gravitational waves generation. To do so, as shown in our previous article, we need to know some pulsars' observable quantities such as: periods and their time derivatives, and estimated distances to the Earth. Moreover, we also need to know the pulsars' masses and radii, for which, in here we are adopting current fiducial values. Our results show that the gravitational wave amplitude is at best $h \sim 10^{-28}$. This leads to a pessimistic prospect for the detection of gravitational waves generated by these pulsars, even for Advanced LIGO and Advanced Virgo, and the planned Einstein Telescope, whether the ellipticity has magnetic origin.