Matrix matching yields improved quasi-bound spectra (fine structure + decay widths) for a massive Dirac field on RN, and branch-cut analysis plus simulations reveal an intermediate oscillatory power law followed by a QBS-driven t^{-5/6} exp(-η t^{1/3}) far-late-time regime.
Probing Axions with Event Horizon Telescope Polarimetric Measurements
6 Pith papers cite this work. Polarity classification is still indexing.
abstract
With high spatial resolution, polarimetric imaging of a supermassive black hole, like M87$^\star$ or Sgr A$^\star$, by the Event Horizon Telescope can be used to probe the existence of ultralight bosonic particles, such as axions. Such particles can accumulate around a rotating black hole through the superradiance mechanism, forming an axion cloud. When linearly polarized photons are emitted from an accretion disk near the horizon, their position angles oscillate due to the birefringent effect when traveling through the axion background. In particular, the observations of supermassive black holes M87$^\star$ (Sgr A$^\star$) can probe the dimensionless axion-photon coupling $c = 2 \pi g_{a \gamma} f_a$ for axions with mass around $O(10^{-20})$~eV ($O( 10^{-17}$)~eV) and decay constant $f_a < O(10^{16})$ GeV, which is complimentary to other axion measurements.
citation-role summary
citation-polarity summary
roles
background 2polarities
background 2representative citing papers
Superradiant axion clouds around black holes can undergo gravitational superfluorescence via a seeded coherent quadrupolar transition, leading to a detectable delayed gravitational-wave pulse.
Collective nucleon scattering in neutron-star matter suppresses the effective absorption of ultralight bosons at the long wavelengths relevant for superradiance, weakening the link between stellar cooling bounds and superradiant instability rates.
Bound states of a massive scalar field around topological stars form strictly normal modes, producing a hydrogen-like spectrum when the Compton wavelength exceeds the star size and localized states otherwise.
MHD simulations indicate that SKA-Mid Band 5a can detect filamentary polarized emission from ICM magnetic fields at high resolution and sensitivity, allowing inference of turbulence driving scales.
citing papers explorer
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Quasi-bound states and late-time evolution of a massive fermion around a Reissner-Nordstr\"{o}m black hole
Matrix matching yields improved quasi-bound spectra (fine structure + decay widths) for a massive Dirac field on RN, and branch-cut analysis plus simulations reveal an intermediate oscillatory power law followed by a QBS-driven t^{-5/6} exp(-η t^{1/3}) far-late-time regime.
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Gravitational superfluorescence from superradiant axion clouds
Superradiant axion clouds around black holes can undergo gravitational superfluorescence via a seeded coherent quadrupolar transition, leading to a detectable delayed gravitational-wave pulse.
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Stellar Superradiance and Low-Energy Absorption in Dense Nuclear Media
Collective nucleon scattering in neutron-star matter suppresses the effective absorption of ultralight bosons at the long wavelengths relevant for superradiance, weakening the link between stellar cooling bounds and superradiant instability rates.
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Gravitational Atoms from Topological Stars
Bound states of a massive scalar field around topological stars form strictly normal modes, producing a hydrogen-like spectrum when the Compton wavelength exceeds the star size and localized states otherwise.
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Unraveling the Imprints of Fluctuation-dynamo on the Intracluster Medium with the SKA
MHD simulations indicate that SKA-Mid Band 5a can detect filamentary polarized emission from ICM magnetic fields at high resolution and sensitivity, allowing inference of turbulence driving scales.
- Relativistic frequency shifts in gravitational waves from axion clouds