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

   Continuous gravitational waves are nearly monochromatic, long-lasting signals that are expected to be produced by rapidly rotating non-axisymmetric neutron stars and may also come from more exotic sources such as the inspiral of dark-matter objects or superradiant emission of axion-like particles around black holes.

    

   Despite numerous detections of gravitational waves from compact binary coalescences, continuous gravitational waves have yet to be detected. One approach to search for CWs is through broad parameter range searches, where the waveform parameters of the signal and the source location are unknown. These types of searches are among the most computationally intensive, often requiring months of processing on large supercomputer clusters.

    

   We present our latest broad parameter range search results for continuous gravitational waves in LIGO O3 public data for high frequency signals greater than 800Hz. Searching for such high frequency continuous gravitational wave signals allows one to probe interesting regimes of source ellipticity. We present the most constraining frequentist upper limits on this source ellipticity as well as on the detectable intrinsic CW amplitude in this parameter range to date.