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Title: First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole

Journal Article · · The Astrophysical Journal. Letters (Online)
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We present the first Event Horizon Telescope (EHT) images of M87, using observations from April 2017 at 1.3 mm wavelength. These images show a prominent ring with a diameter of ~40 μas, consistent with the size and shape of the lensed photon orbit encircling the "shadow" of a supermassive black hole. The ring is persistent across four observing nights and shows enhanced brightness in the south. To assess the reliability of these results, we implemented a two-stage imaging procedure. In the first stage, four teams, each blind to the others' work, produced images of M87 using both an established method (CLEAN) and a newer technique (regularized maximum likelihood). This stage allowed us to avoid shared human bias and to assess common features among independent reconstructions. In the second stage, we reconstructed synthetic data from a large survey of imaging parameters and then compared the results with the corresponding ground truth images. This stage allowed us to select parameters objectively to use when reconstructing images of M87. Across all tests in both stages, the ring diameter and asymmetry remained stable, insensitive to the choice of imaging technique. We describe the EHT imaging procedures, the primary image features in M87, and the dependence of these features on imaging assumptions.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Laboratory Directed Research and Development (LDRD) Program
Contributing Organization:
The Event Horizon Telescope Collaboration
Grant/Contract Number:
89233218CNA000001
OSTI ID:
1571628
Report Number(s):
LA-UR-19-30387; TRN: US2100335
Journal Information:
The Astrophysical Journal. Letters (Online), Vol. 875, Issue 1; ISSN 2041-8213
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 323 works
Citation information provided by
Web of Science

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Modeling non-thermal emission from the jet-launching region of M 87 with adaptive mesh refinement journal November 2019
Orientation of the crescent image of M 87* journal February 2020
Anisotropic ultracompact Schwarzschild star by gravitational decoupling journal September 2019
Asymptotic safety casts its shadow journal June 2019
Prospects for Wideband VLBI Correlation in the Cloud journal October 2019
Resolving accretion flows in nearby active galactic nuclei with the Event Horizon Telescope journal October 2019
Scale-invariance of black hole accretion: modelling emission from a black hole X-ray binary with relativistic accretion flow simulations journal November 2019
Hunting for extra dimensions in the shadow of M87* journal July 2019
Image of the Janis-Newman-Winicour naked singularity with a thin accretion disk journal July 2019
Influence of geometrical configuration on low angular momentum relativistic accretion around rotating black holes journal August 2019
Observability of spherical photon orbits in near-extremal Kerr black holes journal August 2019
Testing the Schwarzschild metric in a strong field region with the Event Horizon Telescope journal September 2019
Higher order corrections to deflection angle of massive particles and light rays in plasma media for stationary spacetimes using the Gauss-Bonnet theorem journal November 2019
Charged cosmological black holes: A thorough study of a family of solutions journal November 2019
Photon emission near Myers-Perry black holes in the large dimension limit journal January 2020
Observational signature of a near-extremal Kerr-Sen black hole in the heterotic string theory journal January 2020
Rotating black holes with an anisotropic matter field journal March 2020
Spontaneously Scalarized Kerr Black Holes in Extended Scalar-Tensor–Gauss-Bonnet Gravity journal July 2019
Standard Quantum Limit and Heisenberg Limit in Function Estimation journal January 2020
Weak and strong deflection gravitational lensing by a renormalization group improved Schwarzschild black hole journal December 2019
An environment for sustainable research software in Germany and beyond: current state, open challenges, and call for action journal January 2020
Relativistic Aspects of Accreting Supermassive Black Hole Binaries in Their Natural Habitat: A Review journal May 2019
Relativistic Jets from AGN Viewed at Highest Angular Resolution journal December 2019
Approaching the Black Hole by Numerical Simulations journal April 2019
Black Hole Spin Signature in the Black Hole Shadow of M87 in the Flaring State journal June 2019
Metrics and Motivations for Earth–Space VLBI: Time-resolving Sgr A* with the Event Horizon Telescope journal August 2019
EHT-HOPS Pipeline for Millimeter VLBI Data Reduction journal August 2019
Black Hole Spin Measurement Based on Time-domain VLBI Observations of Infalling Gas Clouds journal December 2019
Impact of a Spinning Supermassive Black Hole on the Orbit and Gravitational Waves of a Nearby Compact Binary journal December 2019
Kinematics of the M87 Jet in the Collimation Zone: Gradual Acceleration and Velocity Stratification journal December 2019
First M87 Event Horizon Telescope Results. III. Data Processing and Calibration journal April 2019
First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring journal April 2019
First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole journal April 2019
VLBI imaging of black holes via second moment regularization journal September 2019
Magnetically charged black holes from non-linear electrodynamics and the Event Horizon Telescope journal February 2020
Measurement of the spin of the M87 black hole from its observed twisted light journal November 2019
Testing the rotational nature of the supermassive object M87* from the circularity and size of its first image journal August 2019
Influence of the vacuum polarization effect on the motion of charged particles in the magnetic field around a Schwarzschild black hole journal October 2019
Silhouette of M87*: A new window to peek into the world of hidden dimensions journal February 2020
The Brightest Point in Accretion Disk and Black Hole Spin: Implication to the Image of Black Hole M87* journal August 2019
Kerr Black Holes within a Modified Theory of Gravity journal August 2019
The Effects of Finite Distance on the Gravitational Deflection Angle of Light journal November 2019
A 40 Billion Solar-mass Black Hole in the Extreme Core of Holm 15A, the Central Galaxy of Abell 85 journal December 2019
ALMA Observations of the Terahertz Spectrum of Sagittarius A* journal August 2019
The Shadow of a Spherically Accreting Black Hole journal November 2019
Measurement of the spin of the M87 black hole from its observed twisted light text January 2019
An environment for sustainable research software in Germany and beyond: current state, open challenges, and call for action journal January 2020
Standard Quantum Limit and Heisenberg Limit in Function Estimation text January 2018
EHT-HOPS pipeline for millimeter VLBI data reduction text January 2019
Observability of spherical photon orbits in near-extremal Kerr black holes text January 2019
Measurement of the spin of the M87 black hole from its observed twisted light text January 2019
Anisotropic ultracompact Schwarzschild star by gravitational decoupling text January 2019
The effects of finite distance on the gravitational deflection angle of light text January 2019
Metrics and Motivations for Earth-Space VLBI: Time-Resolving Sgr A* with the Event Horizon Telescope text January 2019
First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring text January 2019
Resolving accretion flows in nearby active galactic nuclei with the Event Horizon Telescope text January 2019
Approaching the black hole by numerical simulations text January 2019
VLBI imaging of black holes via second moment regularization text January 2019
Impact of a Spinning Supermassive Black Hole on the Orbit and Gravitational Waves of a Nearby Compact Binary text January 2019
Orientation of the crescent image of M 87* text January 2019
Testing the Schwarzschild metric in a strong field region with the Event Horizon Telescope text January 2019
Silhouette of M87*: A new window to peek into the world of hidden dimensions text January 2019
The Shadow of a Spherically Accreting Black Hole text January 2019
Lensing by Kerr Black Holes text January 2019
Kinematics of the M87 jet in the collimation zone: gradual acceleration and velocity stratification text January 2019
Observational signature of a near-extremal Kerr-Sen black hole in the heterotic string theory text January 2019

Figures / Tables (52)

μas. Each point denotes a single scan, which range in duration from 4 to 7 minutes. Bottom panels: the full baseline coverage on M87 for each observation. In all panels, the dashed circles show baseline lengths corresponding to the indicated fringe spacings (0.2" for the upper-left panel; 25 and 50 μas for the remaining panels)." data-ostiid="1571628">
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