230 GHz VLBI observations of M87: event-horizon-scale structure at the enhanced very-high-energy $\gamma$-ray state in 2012

Abstract

We report on 230 GHz (1.3 mm) VLBI observations of M87 with the Event Horizon Telescope using antennas on Mauna Kea in Hawaii, Mt. Graham in Arizona and Cedar Flat in California. For the first time, we have acquired 230 GHz VLBI interferometric phase information on M87 through measurement of closure phase on the triangle of long baselines. Most of the measured closure phases are consistent with 0${}^{\circ }$ as expected by physically-motivated models for 230 GHz structure such as jet models and accretion disk models. The brightness temperature of the event-horizon-scale structure is $\sim 1\times 10^{10}$ K derived from the compact flux density of $\sim 1$ Jy and the angular size of $\sim 40$ $\mu$as $\sim$ 5.5 $R_{\mathrm{s}}$, which is broadly consistent with the peak brightness of the radio cores at 1-86 GHz located within $\sim 10^2$ $R_{\mathrm{s}}$. Our observations occurred in the middle of an enhancement in very-high-energy (VHE) $\gamma$-ray flux, presumably originating in the vicinity of the central black hole. Our measurements, combined with results of multi-wavelength observations, favor a scenario in which the VHE region has an extended size of $\sim$20-60 $R_{\mathrm{s}}$.

11 pages, 4 figures, accepted to ApJ

References in corpus (15)

• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• Jet Launching Structure Resolved Near the Supermassive Black Hole in M87
• Magnetic acceleration of relativistic AGN jets
• RadioAstron -- a Telescope with a Size of 300 000 km: Main Parameters and First Observational Results
• The Submillimeter Bump in Sgr A* from Relativistic MHD Simulations
• The Inner Jet of the Radio Galaxy M87
• Production of TeV gamma-radiation in the vicinity of the supermassive black hole in the giant radiogalaxy M87
• Spine-sheath layer radiative interplay in subparsec-scale jets and the TeV emission from M87
• Variable TeV emission as a manifestation of jet formation in M87?
• Gamma-ray flares from red giant/jet interactions in AGN
• Imaging the Supermassive Black Hole Shadow and Jet Base of M87 with the Event Horizon Telescope
• A synchrotron self-Compton scenario for the very high energy gamma-ray emission of the radiogalaxy M87
• Magnetization degree at the jet base of M87 derived from the event horizon telescope data: Testing magnetically driven jet paradigm
• A strong radio brightening at the jet base of M87 during the elevated very-high-energy gamma-ray state in 2012
• Relativistic electrons and magnetic field of the M87 jet on ~ten Schwarzschild radii scale

Cited by in corpus (41)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
• First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
• Imaging the Schwarzschild-radius-scale Structure of M87 with the Event Horizon Telescope using Sparse Modeling
• Super-resolution Full Polarimetric Imaging for Radio Interferometry with Sparse Modeling
• Faraday rotation in the jet of M87 inside the Bondi radius: indication of winds from hot accretion flows confining the relativistic jet
• State-of-the-art energetic and morphological modelling of the launching site of the M87 jet
• Simulations of imaging the event horizon of Sagittarius A* from space
• Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon Telescope
• Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales
• Jet collimation and acceleration in the giant radio galaxy NGC 315
• Linear polarization in the nucleus of M87 at 7 mm and 1.3 cm
• Constraint on the black-hole spin of M87 from the accretion-jet model
• Black Hole Spin Signature in the Black Hole Shadow of M87 in the Flaring State
• Magnetospheric Gamma-Ray Emission in Active Galactic Nuclei
• The Galactic Center as a laboratory for theories of gravity and dark matter
• Positron Effects on Polarized Images and Spectra from Jet and Accretion Flow Models of M87* and Sgr A*
• Black hole Spin Measurement Based on Time-domain VLBI Observations of Infalling Gas Cloud
• Seeing the unseeable
• Spectral analysis of a parsec-scale jet in M87: Observational constraint on the magnetic field strengths in the jet
• An accretion-jet model for M87: interpreting the spectral energy distribution and Faraday rotation measure
• Ergosphere, photon region structure, and the shadow of a rotating charged Weyl black hole
• Radiation GRMHD simulations of M87: funnel properties and prospects for gap acceleration
• Accretion Flow Morphology in Numerical Simulations of Black Holes from the ngEHT Model Library: The Impact of Radiation Physics
• Blazars at Very High Energies: Emission Modelling
• M87: a cosmic laboratory for deciphering black hole accretion and jet formation
• Density spikes near black holes in self-interacting dark matter halos and indirect detection constraints
• The jet and resolved features of the central supermassive black hole of M 87 observed with EHT
• A comparative study of amplitude calibrations for East-Asia VLBI Network: a-priori and template spectrum methods
• Jet in jet in M87
• Jet Collimation and Acceleration in the Flat Spectrum Radio Quasar 1928+738
• Constraints on Black Hole Jet Models Used As Diagnostic Tools of Event Horizon Telescope Observations of M87
• The Japanese Vision for the Black Hole Explorer Mission
• A Jet Source of Event Horizon Telescope Correlated Flux in M87
• A proof-of-concept neural network for inferring parameters of a black hole from partial interferometric images of its shadow
• Investigating the Disk-Jet Structure in M87 through Flux Separation in the Linear and Circular Polarization Images
• Impact of non-thermal particles on the spectral and structural properties of M87