Rotating black holes with primary scalar hair in beyond Horndeski gravity produce shadows whose diameter increases for negative Q and whose distortion increases for positive Q, with EHT bounds on M87* restricting but not ruling out the (a, Q) parameter space.
The Structure and Dynamics of the Sub-parsec Scale Jet in M87 Based on 50 VLBA Observations Over 17 Years at 43 GHz
6 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
The central radio source in M87 provides the best opportunity to study jet formation because it has a large angular size for the gravitational radius of the black hole and has a bright jet that is well resolved by VLBI observations. We present intensive monitoring observations from 2007 and 2008, plus roughly annual observations that span 17 years, all made with the the Very Long Baseline Array at 43 GHz with a resolution of about 30 by 60 Rs. Our high-dynamic-range images clearly show the wide-opening-angle structure and the counter-jet. The jet and counter-jet are nearly symmetric in the inner 1.5 milli-arcseconds (mas; 0.12 pc in projection) with both being edge brightened. Both show deviations from parabolic shape in the form of an initial rapid expansion and subsequent contraction followed by further rapid expansion and, beyond the visible counter-jet, subsequent collimation. Proper motions and counter-jet/jet intensity ratios both indicate acceleration from apparent speeds of $\lesssim 0.5c$ to $\gtrsim 2c$ in the inner about 2 mas and suggest a helical flow. The jet displays a sideways shift with an approximately 8 to 10 year quasi-periodicity. The shift propagates outwards non-ballistically and significantly more slowly than the flow speed revealed by the fastest moving components. Polarization data show a systematic structure with magnetic field vectors that suggest a toroidal field close to the core.
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2026 6verdicts
UNVERDICTED 6representative citing papers
Lorentzian-Euclidean black holes produce excess inner-shadow intensity and accumulate energy at the horizon with backreaction unlike stable light rings.
Simulations of accreting black holes in standard and complex spacetimes indicate that magnetic geometry, quantum corrections, and binary dynamics influence flares, precession, photon rings, and multi-wavelength variability, with potential EHT constraints.
2D RMHD simulations show recollimation distance decreases monotonically with magnetization σ, converging to z_MHD/z_HD ∝ (B₀²/P_ext)^{-1/3} in the high-σ regime, with toroidal fields producing localized emission knots and poloidal fields shifting the zone downstream.
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}.
Reports results from two searches for new radio lenses in existing surveys and discusses the completeness of the population usable for constraining dark matter properties via astrometric perturbations.
citing papers explorer
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Rotating Black Holes with Primary Scalar Hair: Shadow Signatures in Beyond Horndeski Gravity
Rotating black holes with primary scalar hair in beyond Horndeski gravity produce shadows whose diameter increases for negative Q and whose distortion increases for positive Q, with EHT bounds on M87* restricting but not ruling out the (a, Q) parameter space.
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Shadow signatures and energy accumulation in Lorentzian-Euclidean black holes
Lorentzian-Euclidean black holes produce excess inner-shadow intensity and accumulate energy at the horizon with backreaction unlike stable light rings.
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GRMHD and GRRT Simulations of Black Hole Accretion: Flares, Precession, and Complex Spacetimes
Simulations of accreting black holes in standard and complex spacetimes indicate that magnetic geometry, quantum corrections, and binary dynamics influence flares, precession, photon rings, and multi-wavelength variability, with potential EHT constraints.
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2D magnetohydrodynamic jet simulations: properties of recollimation shocks
2D RMHD simulations show recollimation distance decreases monotonically with magnetization σ, converging to z_MHD/z_HD ∝ (B₀²/P_ext)^{-1/3} in the high-σ regime, with toroidal fields producing localized emission knots and poloidal fields shifting the zone downstream.
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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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Taking Inventory of the Most Promising Lensed Radio Sources for Constraining Fundamental Properties of Dark Matter
Reports results from two searches for new radio lenses in existing surveys and discusses the completeness of the population usable for constraining dark matter properties via astrometric perturbations.