Semicoherent analysis method to search for continuous gravitational waves emitted by ultralight boson clouds around spinning black holes

This is the authors' abstract. We don't add key points for this paper.

As a consequence of superradiant instability induced in Kerr black holes, ultralight boson clouds can be a source of persistent gravitational waves, potentially detectable by current and future gravitational-wave detectors. These signals have been predicted to be nearly monochromatic, with a small steady frequency increase (spin-up), but given the several assumptions and simplifications done at theoretical level, it is wise to consider, from the data analysis point of view, a broader class of gravitational signals in which the phase (or the frequency) slightly wander in time. Also other types of sources, e.g., neutron stars in which a torque balance equilibrium exists between matter accretion and emission of persistent gravitational waves, would fit in this category. In this paper we present a robust and computationally cheap analysis pipeline devoted to the search of such kind of signals. We provide a full characterization of the method, through both a theoretical sensitivity estimation and through the analysis of synthetic data in which simulated signals have been injected. The search setup for both all-sky searches and higher sensitivity directed searches is discussed.