Probing black hole charge from the binary black hole inspiral

Recent gravitational wave (GW) observations have enabled us to look beyond the standard paradigm of gravitational physics, namely general relativity (GR). Along with the mass and the angular momentum, which typical astrophysical black holes (BHs) are endowed with, theories beyond GR generically induce charge to these BHs. Notably, for BHs carrying the extra charge hair, we expect the BH absorption effects to modify accordingly and alter the tidal heating terms. Hence, the inclusion of the corrections in the GW waveform model, arising from the BH charge, allows us to test the consistency of the observed binaries with Kerr BHs in GR. We compute the explicit dependence of the binary inspiral phase on the charge parameter arising from the tidal heating effect and study the measurability of the same from GW observations of binary mergers. Specifically, we employ the TaylorF2 waveform model, which accurately models the inspiral evolution of an aligned-spin binary merger, and Bayesian analysis-based GW data inference to measure the charge parameter for a selected set of detected binaries. We also present a detailed simulation study to investigate the possibility of measuring the charge parameter from binaries with different masses, spins and source locations. The analysis of selected GW events from the third GW transient catalog shows that the charge parameter constraints are poor from the observed signals with the current sensitivity. In contrast, the simulation studies indicate that the spinning binaries with significant mass asymmetry provide the best constraints on the BH charge parameter. Finally, we study the prospects of measuring the BH charge parameter from a future GW detector with improved sensitivity.