GW241011 data shows consistency with Kerr black holes for both quadrupole and octupole moments and delivers the first observational bounds on spin-induced octupole deviations.
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Testing the nature of dark compact objects: a status report
Canonical reference. 88% of citing Pith papers cite this work as background.
abstract
Very compact objects probe extreme gravitational fields and may be the key to understand outstanding puzzles in fundamental physics. These include the nature of dark matter, the fate of spacetime singularities, or the loss of unitarity in Hawking evaporation. The standard astrophysical description of collapsing objects tells us that massive, dark and compact objects are black holes. Any observation suggesting otherwise would be an indication of beyond-the-standard-model physics. Null results strengthen and quantify the Kerr black hole paradigm. The advent of gravitational-wave astronomy and precise measurements with very long baseline interferometry allow one to finally probe into such foundational issues. We overview the physics of exotic dark compact objects and their observational status, including the observational evidence for black holes with current and future experiments.
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A classification of admissible energy density profiles with bounded Kretschmann scalar yields a unified framework for regular static spherically symmetric spacetimes satisfying the weak energy condition, recovering known models and producing new families with hypergeometric and other closed forms.
Axial tidal Love numbers for black holes in anisotropic fluid environments are derived analytically and numerically, with non-compact support density profiles producing logarithmic terms that obstruct standard tidal matching due to the lack of a strictly vacuum exterior.
3D GRMHD simulations of accretion onto a JMN-1 horizonless singularity produce a magnetically arrested disk with an accretion rate of ~3e-6 Eddington matching M87* observations and EHT-consistent images, plus central brightness inside the shadow as a discriminant from black holes.
Viscous neutron stars have new families of axial oscillation modes without perfect-fluid counterparts, featuring mode avoidance and long-lived modes.
GreyRing model based on greybody factors reproduces numerical relativity ringdown signals with mismatches of order 10^{-6} and enables a new post-merger consistency test of general relativity applied to GW250114.
Higher-order terms in an infinite tower of higher-derivative gravity regularize a 5D Proca-Maxwell system, creating frozen regular cores that mimic extremal black holes and satisfy all energy conditions.
Analytic gravitational waveforms from radial test-particle infall into a thin-shell traversable wormhole exhibit a characteristic pulse-gap structure from repeated throat crossings and lie within reach of ground-based detectors at ~500 Mpc.
Monopole bags in axionic backgrounds gravitationally collapse into horizonless states or dyonic regular black holes that evade singularities while retaining axionic hair.
Leading-order cubic-curvature corrections to scalar quasinormal modes of black holes with spins up to 0.99M are computed numerically for modes up to l=5 with relative errors below 10^{-4}.
Lattice regularization of Rindler QFT shows the Unruh effect survives operationally for distant observables even though exact thermality is lost at the state level, with wave packets reflected at a stretched horizon of order the cutoff.
Quasinormal frequencies and greybody factors for massless scalar and electromagnetic perturbations in Euler-Heisenberg black holes with perfect fluid dark matter are calculated via AIM and sixth-order WKB, showing that charge Q, nonlinearity a, dark matter λ, and angular number l modify effectivepot
For a specific R=0 wormhole, the magnetic Love number for ℓ=2 vanishes to linear order in the regularization parameter under static axial gravitational perturbations.
Fitting GRAVITY flare astrometry to solitonic boson star models requires masses larger than 4.3 million solar masses, with more diffuse models yielding values closer to the standard black hole mass and thus placing stringent but incomplete constraints on such interpretations of Sgr A*.
A logarithmic correction to Schwarzschild in static spherical symmetry obeys all classical energy conditions and serves as an effective exterior for horizon-bearing and horizonless compact objects.
Simulation-based inference reliably extracts physical parameters from noisy spectra of analogue black holes.
LISA EMRIs can constrain deviations from Kerr equatorial symmetry to 10^{-2} and axial symmetry to 10^{-3} using Analytic Kludge waveforms and Fisher analysis.
LISA can constrain non-axisymmetric mass quadrupole deformations at the 10^{-3} level and axisymmetric mass octupole deformations at the 10^{-2} level in EMRI signals to test fuzzball proposals.
GW250114 data confirm the remnant black hole ringdown frequencies lie within 30% of Kerr predictions and that the final horizon area is larger than the sum of the progenitors' areas to high credibility.
Bayesian analysis shows current near-IR astrometry data cannot distinguish massive boson stars from Schwarzschild black holes for Sgr A*.
Numerical backward ray-tracing shows that the inner shadow size shrinks with the Gauss-Bonnet coupling while polarization direction near the shadow and photon ring shifts noticeably, and combining both observables yields stronger constraints than either alone.
No evidence for physics beyond general relativity is found in the analysis of 15 GW events from GWTC-3, with consistency in residuals, PN parameters, and remnant properties.
A review summarizing the state of the art in black hole quasinormal modes, ringdown waveform modeling, current LIGO-Virgo-KAGRA observations, and prospects for LISA and next-generation detectors.
citing papers explorer
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Testing the Kerr hypothesis beyond the quadrupole with GW241011
GW241011 data shows consistency with Kerr black holes for both quadrupole and octupole moments and delivers the first observational bounds on spin-induced octupole deviations.
-
Families of regular spacetimes and energy conditions
A classification of admissible energy density profiles with bounded Kretschmann scalar yields a unified framework for regular static spherically symmetric spacetimes satisfying the weak energy condition, recovering known models and producing new families with hypergeometric and other closed forms.
-
Axial tidal Love numbers of black holes in matter environments
Axial tidal Love numbers for black holes in anisotropic fluid environments are derived analytically and numerically, with non-compact support density profiles producing logarithmic terms that obstruct standard tidal matching due to the lack of a strictly vacuum exterior.
-
GRMHD accretion beyond the black hole paradigm: Light from within the shadow
3D GRMHD simulations of accretion onto a JMN-1 horizonless singularity produce a magnetically arrested disk with an accretion rate of ~3e-6 Eddington matching M87* observations and EHT-consistent images, plus central brightness inside the shadow as a discriminant from black holes.
-
Axial Oscillations of Viscous Neutron Stars
Viscous neutron stars have new families of axial oscillation modes without perfect-fluid counterparts, featuring mode avoidance and long-lived modes.
-
Novel ringdown tests of general relativity with black hole greybody factors
GreyRing model based on greybody factors reproduces numerical relativity ringdown signals with mismatches of order 10^{-6} and enables a new post-merger consistency test of general relativity applied to GW250114.
-
Proca-Maxwell System in an Infinite Tower of Higher-Derivative Gravity
Higher-order terms in an infinite tower of higher-derivative gravity regularize a 5D Proca-Maxwell system, creating frozen regular cores that mimic extremal black holes and satisfy all energy conditions.
-
Gravitational Waves from a Black Hole Falling Radially into a Thin-Shell Traversable Wormhole
Analytic gravitational waveforms from radial test-particle infall into a thin-shell traversable wormhole exhibit a characteristic pulse-gap structure from repeated throat crossings and lie within reach of ground-based detectors at ~500 Mpc.
-
Gravitational Properties of the Monopole Bag
Monopole bags in axionic backgrounds gravitationally collapse into horizonless states or dyonic regular black holes that evade singularities while retaining axionic hair.
-
Ringing of rapidly rotating black holes in effective field theory
Leading-order cubic-curvature corrections to scalar quasinormal modes of black holes with spins up to 0.99M are computed numerically for modes up to l=5 with relative errors below 10^{-4}.
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Rindler Physics with a UV Cutoff on the Lattice
Lattice regularization of Rindler QFT shows the Unruh effect survives operationally for distant observables even though exact thermality is lost at the state level, with wave packets reflected at a stretched horizon of order the cutoff.
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Quasinormal modes of massless scalar and electromagnetic perturbations for Euler Heisenberg black holes surrounded by perfect fluid dark matter
Quasinormal frequencies and greybody factors for massless scalar and electromagnetic perturbations in Euler-Heisenberg black holes with perfect fluid dark matter are calculated via AIM and sixth-order WKB, showing that charge Q, nonlinearity a, dark matter λ, and angular number l modify effectivepot
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Can wormholes have vanishing Love numbers?
For a specific R=0 wormhole, the magnetic Love number for ℓ=2 vanishes to linear order in the regularization parameter under static axial gravitational perturbations.
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Testing solitonic boson star interpretations of Sagittarius A* with near-infrared flare astrometry
Fitting GRAVITY flare astrometry to solitonic boson star models requires masses larger than 4.3 million solar masses, with more diffuse models yielding values closer to the standard black hole mass and thus placing stringent but incomplete constraints on such interpretations of Sgr A*.
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Energy conditions in static, spherically symmetric spacetimes and effective geometries
A logarithmic correction to Schwarzschild in static spherical symmetry obeys all classical energy conditions and serves as an effective exterior for horizon-bearing and horizonless compact objects.
-
Spectroscopy of analogue black holes using simulation-based inference
Simulation-based inference reliably extracts physical parameters from noisy spectra of analogue black holes.
-
Probing Kerr Symmetry Breaking with LISA Extreme-Mass-Ratio Inspirals
LISA EMRIs can constrain deviations from Kerr equatorial symmetry to 10^{-2} and axial symmetry to 10^{-3} using Analytic Kludge waveforms and Fisher analysis.
-
Are Black Holes Fuzzballs? Probing Horizon-Scale Structure with LISA
LISA can constrain non-axisymmetric mass quadrupole deformations at the 10^{-3} level and axisymmetric mass octupole deformations at the 10^{-2} level in EMRI signals to test fuzzball proposals.
-
GW250114: testing Hawking's area law and the Kerr nature of black holes
GW250114 data confirm the remnant black hole ringdown frequencies lie within 30% of Kerr predictions and that the final horizon area is larger than the sum of the progenitors' areas to high credibility.
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Bayesian Analysis of Massive Boson Star Models for Sagittarius A* Using Near-Infrared Astrometry Data
Bayesian analysis shows current near-IR astrometry data cannot distinguish massive boson stars from Schwarzschild black holes for Sgr A*.
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Unveiling Inner Shadows and Polarization Signatures of Rotating Einstein-Gauss-Bonnet Black Holes
Numerical backward ray-tracing shows that the inner shadow size shrinks with the Gauss-Bonnet coupling while polarization direction near the shadow and photon ring shifts noticeably, and combining both observables yields stronger constraints than either alone.
-
Tests of General Relativity with GWTC-3
No evidence for physics beyond general relativity is found in the analysis of 15 GW events from GWTC-3, with consistency in residuals, PN parameters, and remnant properties.
-
Black hole spectroscopy: from theory to experiment
A review summarizing the state of the art in black hole quasinormal modes, ringdown waveform modeling, current LIGO-Virgo-KAGRA observations, and prospects for LISA and next-generation detectors.
- The Science of the Einstein Telescope