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.
First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
12 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
We present the calibration and reduction of Event Horizon Telescope (EHT) 1.3mm radio wavelength observations of the supermassive black hole candidate at the center of the radio galaxy M87 and the quasar 3C 279, taken during the 2017 April 5-11 observing campaign. These global very long baseline interferometric observations include for the first time the highly sensitive Atacama Large Millimeter/submillimeter Array (ALMA); reaching an angular resolution of 25 micro-as, with characteristic sensitivity limits of ~1 mJy on baselines to ALMA and ~10 mJy on other baselines. The observations present challenges for existing data processing tools, arising from the rapid atmospheric phase fluctuations, wide recording bandwidth, and highly heterogeneous array. In response, we developed three independent pipelines for phase calibration and fringe detection, each tailored to the specific needs of the EHT. The final data products include calibrated total intensity amplitude and phase information. They are validated through a series of quality assurance tests that show consistency across pipelines and set limits on baseline systematic errors of 2% in amplitude and 1 degree in phase. The M87 data reveal the presence of two nulls in correlated flux density at ~3.4 and ~8.3 giga-lambda and temporal evolution in closure quantities, indicating intrinsic variability of compact structure on a timescale of days, or several light-crossing times for a few billion solar-mass black hole. These measurements provide the first opportunity to image horizon-scale structure in M87.
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VAPOLA releases multi-epoch multi-band ALMA full-Stokes products and polarimetric fits for AGN and Sgr A* via an automated pipeline and web portal.
Machine learning on simulated images identifies that flux eruption events cause more diffuse, polarized, lower-flux millimeter emission with decreased Q-U loop rotation rate, achieving ~80% accuracy with random forests on summary statistics.
Three distinct non-minimal curvature-EM couplings produce different enlargements or reductions of black hole shadows and alter photon ring separations in characteristic ways.
Boson stars in teleparallel gravity with nonminimal coupling show negative energy density and energy-condition violation in excited states, with EMRI waveforms potentially detectable by LISA.
SKAMPI achieved first successful S-band VLBI fringes with EVN and LBA stations, confirming end-to-end interoperability and adding long African baselines.
Analysis of how string cloud parameter a and dark matter parameter α alter MBO, ISCO, periodic orbits indexed by q, and the gravitational waveforms generated by those orbits in a modified Schwarzschild spacetime.
Photon-axion conversion near Kerr black holes produces dimming of photon spectral luminosity that increases with black hole spin, magnetic field strength, and photon-axion coupling, most efficiently at high frequencies.
Tidal forces in the Simpson-Visser spacetime produce Roche radii for stars that depend on observer type and regularization, with some disruptions occurring outside the event horizon for supermassive black holes.
No photon-ALP conversion signal found in HAWC data from M87, producing competitive constraints excluding ALP masses of 10^{-8} to 10^{-6} eV for couplings above 5×10^{-12} GeV^{-1}.
Rotating Ayón-Beato–García black holes cast smaller, spin-asymmetric shadows whose diameters, compared with EHT data, bound the nonlinear-electrodynamics charge while leaving Kerr viable.
In Kruglov NED, small positive q can create stable photon orbits and reshape black-hole shadows and accretion images even when the metric stays close to Reissner–Nordström.
citing papers explorer
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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.
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VAPOLA -- A multi-year, multi-band polarization survey of AGN and Sgr A* at mm wavelengths with ALMA I. Survey Overview and Science-Ready Archival Products
VAPOLA releases multi-epoch multi-band ALMA full-Stokes products and polarimetric fits for AGN and Sgr A* via an automated pipeline and web portal.
-
Identifying Observational Signatures of Flux Eruption Events in Supermassive Black Hole Accretion Flows with Machine Learning
Machine learning on simulated images identifies that flux eruption events cause more diffuse, polarized, lower-flux millimeter emission with decreased Q-U loop rotation rate, achieving ~80% accuracy with random forests on summary statistics.
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Photon rings and shadows of black holes with non-minimal couplings between curvature and electromagnetic field
Three distinct non-minimal curvature-EM couplings produce different enlargements or reductions of black hole shadows and alter photon ring separations in characteristic ways.
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Boson Stars in Teleparallel Gravity with a Nonminimally Coupled Field: The Violation of Energy Conditions and Gravitational Waveforms from EMRIs
Boson stars in teleparallel gravity with nonminimal coupling show negative energy density and energy-condition violation in excited states, with EMRI waveforms potentially detectable by LISA.
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VLBI with SKAMPI, the SKA-Mid MPIfR dish demonstrator
SKAMPI achieved first successful S-band VLBI fringes with EVN and LBA stations, confirming end-to-end interoperability and adding long African baselines.
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Periodic orbits and gravitational waveforms around a Schwarzschild black hole with a cloud of strings embedded in perfect fluid dark matter
Analysis of how string cloud parameter a and dark matter parameter α alter MBO, ISCO, periodic orbits indexed by q, and the gravitational waveforms generated by those orbits in a modified Schwarzschild spacetime.
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Dimming of Photon Ring due to Photon-Axion Conversion around Kerr Black Holes
Photon-axion conversion near Kerr black holes produces dimming of photon spectral luminosity that increases with black hole spin, magnetic field strength, and photon-axion coupling, most efficiently at high frequencies.
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Roche limit and stellar disruption in the Simpson--Visser spacetime
Tidal forces in the Simpson-Visser spacetime produce Roche radii for stars that depend on observer type and regularization, with some disruptions occurring outside the event horizon for supermassive black holes.
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Constraints on axion-like particles from ultra-high-energy observations of M87 with the HAWC observatory
No photon-ALP conversion signal found in HAWC data from M87, producing competitive constraints excluding ALP masses of 10^{-8} to 10^{-6} eV for couplings above 5×10^{-12} GeV^{-1}.
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Observational Signatures of Rotating Ay\'{o}n-Beato-Garc\'{i}a Black Holes: Shadows, Accretion Disks and Images
Rotating Ayón-Beato–García black holes cast smaller, spin-asymmetric shadows whose diameters, compared with EHT data, bound the nonlinear-electrodynamics charge while leaving Kerr viable.
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Photon Propagation and Black Hole Imaging in Kruglov Nonlinear Electrodynamics
In Kruglov NED, small positive q can create stable photon orbits and reshape black-hole shadows and accretion images even when the metric stays close to Reissner–Nordström.