High-frequency continuous gravitational waves searched in LIGO O3 public data with Einstein@Home

Abstract

We search for nearly-monochromatic gravitational wave signals with frequencies $800.0\text{Hz}\le f\le 1686.0\text{Hz}$ and spin-down $-2.7\times 10^{-9}\text{Hz}{\text{s}}^{-1}\le \dot{f}\le 0.2\times 10^{-9}\text{Hz}{\text{s}}^{-1}$. We use LIGO O3 public data from the Hanford and Livingston detectors and deploy this search on the Einstein@Home volunteer-computing project. This is the most sensitive search carried out to date in this parameter space. Our results are consistent with a non-detection. We set upper limits on the gravitational wave amplitude $h_0$ and translate these to upper limits on neutron star ellipticity and on r-mode amplitude. The most stringent upper limits are at $800\text{Hz}$ with $h_0=1.32\times 10^{-25}$, at the $90\%$ confidence level. Searching in the high frequency bands allows us to probe astrophysically interesting ellipticities with our results excluding isolated neutron stars rotating faster than $2.5\text{ms}$ with ellipticities $\hat{I}\mu \ge 1.96\times 10^{-8}\left[\frac{d}{100\text{pc}}\right]$ within a distance $d$ from Earth. Our results also exclude r-mode amplitudes $\hat{I}\pm \ge 7\times 10^{-7}\left[\frac{d}{100\text{pc}}\right]$ for neutron stars stars spinning faster than 400 Hz.

11 Pages, 9 Figures - Updated references / Added reference for supplementary materials - Fixed spelling of author name on arXiv