Upper limits on gravitational wave emission from 78 radio pulsars

TL;DR

This paper reports new upper limits on gravitational wave emissions from 78 radio pulsars, including those in binary systems, using combined data from LIGO and GEO600, with improved sensitivity over previous results.

Contribution

First measurements of gravitational wave upper limits for 56 pulsars in binary systems, and improved limits for 22 others, using combined data from multiple detectors and runs.

Findings

Upper limits on gravitational strain as low as 2.6e-25.

Constraints on pulsar ellipticity, e.g., less than 10^{-6} for PSRJ2124-3358.

Strain limit for Crab pulsar close to spin-down limit.

Abstract

We present upper limits on the gravitational wave emission from 78 radio pulsars based on data from the third and fourth science runs of the LIGO and GEO600 gravitational wave detectors. The data from both runs have been combined coherently to maximise sensitivity. For the first time pulsars within binary (or multiple) systems have been included in the search by taking into account the signal modulation due to their orbits. Our upper limits are therefore the first measured for 56 of these pulsars. For the remaining 22, our results improve on previous upper limits by up to a factor of 10. For example, our tightest upper limit on the gravitational strain is 2.6e-25 for PSRJ1603-7202, and the equatorial ellipticity of PSRJ2124-3358 is less than 10^{-6}. Furthermore, our strain upper limit for the Crab pulsar is only 2.2 times greater than the fiducial spin-down limit.