Ultralight boson cloud depletion in binary systems

Abstract

Ultralight scalars can extract rotational energy from astrophysical black holes through superradiant instabilities, forming macroscopic boson clouds. This process is most efficient when the Compton wavelength of the boson is comparable to the size of the black hole horizon, i.e. when the "gravitational fine structure constant" $\alpha \equiv G\mu M/\hslash c\sim 1$. If the black hole/cloud system is in a binary, tidal perturbations from the companion can produce resonant transitions between the energy levels of the cloud, depleting it by an amount that depends on the nature of the transition and on the parameters of the binary. Previous cloud depletion estimates considered binaries in circular orbit and made the approximation $\alpha \ll 1$. Here we use black hole perturbation theory to compute instability rates and decay widths for generic values of $\alpha$, and we show that this leads to much larger cloud depletion estimates when $\alpha \gtrsim 0.1$. We also study eccentric binary orbits. We show that in this case resonances can occur at all harmonics of the orbital frequency, significantly extending the range of frequencies where cloud depletion may be observable with gravitational wave interferometers.

12 pages, 6 figures. v2: references added, matches published version

References in corpus (14)

• Ultralight scalars as cosmological dark matter
• A gravitational-wave standard siren measurement of the Hubble constant
• Can environmental effects spoil precision gravitational-wave astrophysics?
• Discovering the QCD Axion with Black Holes and Gravitational Waves
• Instability of the massive Klein-Gordon field on the Kerr spacetime
• Gravitational wave searches for ultralight bosons with LIGO and LISA
• Black holes as particle detectors: evolution of superradiant instabilities
• Stochastic and resolvable gravitational waves from ultralight bosons
• Bosenova collapse of axion cloud around a rotating black hole
• Orbital fingerprints of ultralight scalar fields around black holes
• Forced motion near black holes
• LISA observations of massive black hole mergers: event rates and issues in waveform modelling
• Probing the string axiverse by gravitational waves from Cygnus X-1
• Roche-lobe overflow in eccentric planet-star systems

Cited by in corpus (13)

• Gravitational wave signatures of ultralight vector bosons from black hole superradiance
• Constraints on ultralight scalar bosons within black hole spin measurements from LIGO-Virgo's GWTC-2
• Tidal deformability of dressed black holes and tests of ultralight bosons in extended mass ranges
• Observational properties of relativistic fluid spheres with thin accretion disks
• Growth of accretion driven scalar hair around Kerr black holes
• Axion cloud evaporation during inspiral of black hole binaries -- the effects of backreaction and radiation
• Evolution of binary systems accompanying axion clouds in extreme mass ratio inspirals
• Axion clouds may survive the perturbative tidal interaction over the early inspiral phase of black hole binaries
• Forecasts for Low Spin Black Hole Spectroscopy in Horndeski Gravity
• Tidal forces in dirty black hole spacetimes
• Searching for ultralight bosons with supermassive black hole ringdown
• Probing Particle Physics with Gravitational Waves
• Challenging theories of gravitation: dark matter, compact objects and gravitational waves