Visualising the continuous gravitational-wave sky
The first atlas of the entire sky in continuous gravitational waves
Continuous gravitational waves are emitted by rapidly rotating deformed neutron stars. Detecting them would allow to study their otherwise invisible population in our Galaxy. Researchers from the permanent independent research group “Continuous Gravitational Waves” at the Max Planck Institute for Gravitational Physics in Hannover have analysed public LIGO data from O3a, the first half the third observing run. They created the first atlas of the entire continuous gravitational wave sky. It contains for every point on the sky and in narrow frequency bands information on the search results. No continuous gravitational-wave signal was identified, but the new results place tighter constraints on the population of rapidly rotating neutron stars as emitters of continuous gravitational waves.
We present the first atlas of the continuous gravitational wave sky, produced using LIGO O3a public data. For each 0.045 Hz frequency band and every point on the sky the atlas provides upper limits, signal-to-noise ratios (SNR) and frequencies where the search measures the maximum SNR. The results presented in the atlas are produced with the Falcon pipeline and cover nearly monochromatic gravitational wave signals in the 500-1000 Hz band, with up to ±5 × 10−11 Hz/s frequency derivative. Compared to the most sensitive results previously published (also produced with the Falcon pipeline) our upper limits are 50% more constraining. Neutron stars with ellipticity of 10−8 can be detected up to 150 pc away, while allowing for a large fraction of the stars’ energy to be lost through non-gravitational channels.