First Constraining Upper Limits on Gravitational Wave Emission from NS 1987A in SNR 1987A

TL;DR

This paper reports the first astrophysically consistent search for continuous gravitational waves from NS 1987A, setting new upper limits on GW emission and constraining neutron star properties using advanced LIGO data.

Contribution

It introduces a comprehensive search covering a wide frequency and spin-down range, improving constraints on GW emission from NS 1987A beyond previous limits.

Findings

No gravitational wave signals detected.

Set upper limits on GW strain as low as 2×10^{-25}.

First constraints to beat the age-based spin-down limit.

Abstract

We report on a search for continuous gravitational waves (GWs) from NS 1987A, the neutron star born in SN 1987A. The search covered a frequency band of 75-275 Hz, included a wide range of spin-down parameters for the first time, and coherently integrated 12.8 days of data below 125 Hz and 8.7 days of data above 125 Hz from the second Advanced LIGO observing run. We found no astrophysical signal. We set upper limits on GW emission as tight as an intrinsic strain of $2\times10^{-25}$ at 90\% confidence. The large spin-down parameter space makes this search the first astrophysically consistent one for continuous GWs from NS 1987A. Our upper limits are the first consistent ones to beat an analog of the spin-down limit based on the age of the neutron star, and hence are the first GW observations to put new constraints on NS 1987A.