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The Event Horizon Telescope (EHT) has imaged the shadow of the supermassive black hole in M87. A library of general relativistic magnetohydrodynamics (GMRHD) models was fit to the observational data, providing constraints on black hole…

High Energy Astrophysical Phenomena · Physics 2021-06-09 Freek Roelofs , Christian M. Fromm , Yosuke Mizuno , Jordy Davelaar , Michael Janssen , Ziri Younsi , Luciano Rezzolla , Heino Falcke

The concept of a new space very long baseline interferometry system named the Event Horizon Imager (EHI) has been proposed to dramatically improve black hole imaging and provide precise tests of the theory of general relativity. We…

High Energy Astrophysical Phenomena · Physics 2026-02-04 Anastasia Shlentsova , Freek Roelofs , Sara Issaoun , Jordy Davelaar , Heino Falcke

This study introduces a novel unsupervised medical image feature extraction method that employs spatial stratification techniques. An objective function based on weight is proposed to achieve the purpose of fast image recognition. The…

Image and Video Processing · Electrical Eng. & Systems 2024-06-28 Qishi Zhan , Dan Sun , Erdi Gao , Yuhan Ma , Yaxin Liang , Haowei Yang

While conventional imaging in VLBI provides information only about the relative position between different features of a given source, phase-referenced observations can provide precise positional information with respect to an external…

Astrophysics · Physics 2007-05-23 Eduardo Ros

Using very long baseline interferometry, the Event Horizon Telescope (EHT) collaboration has resolved the shadows of two supermassive black holes. Model comparison is traditionally performed in image space, where imaging algorithms…

The recent advent of the Event Horizon Telescope (EHT) has made direct imaging of supermassive black holes a reality. Simulated images of black holes produced via general relativistic ray tracing and radiative transfer provide a key…

High Energy Astrophysical Phenomena · Physics 2021-05-13 Z. Gelles , B. S. Prather , D. C. M. Palumbo , M. D. Johnson , G. N. Wong , B. Georgiev

Global VLBI imaging at millimeter and sub-millimeter wavelength overcomes the opacity barrier of synchrotron self-absorption in AGN and opens the direct view into sub-pc scale regions not accessible before. Since AGN variability is more…

Generating images from very long baseline interferometric observations poses a difficult, and generally not unique, inversion problem. This problem is simplified by the introduction of constraints, some generic (e.g., positivity of the…

Instrumentation and Methods for Astrophysics · Physics 2022-08-22 Avery E. Broderick , Dominic W. Pesce , Paul Tiede , Hung-Yi Pu , Roman Gold

The Event Horizon Telescope (EHT) is a millimeter very long baseline interferometry (VLBI) array that has imaged the apparent shadows of the supermassive black holes M87* and Sagittarius A*. Polarimetric data from these observations contain…

The Event Horizon Telescope (EHT) is a project to assemble a Very Long Baseline Interferometry (VLBI) network of mm wavelength dishes that can resolve strong field General Relativistic signatures near a supermassive black hole. As planned,…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 Ru-Sen Lu , Avery E. Broderick , Fabien Baron , John D. Monnier , Vincent L. Fish , Sheperd S. Doeleman , Victor Pankratius

General relativity predicts that images of optically thin accretion flows around black holes should generically have a ``photon ring,'' composed of a series of increasingly sharp subrings that correspond to increasingly strongly lensed…

High Energy Astrophysical Phenomena · Physics 2022-10-26 Paul Tiede , Michael D. Johnson , Dominic W. Pesce , Daniel C. M. Palumbo , Dominic O. Chang , Peter Galison

This paper presents a new method to extract image low-level features, namely mix histogram (MH), for content-based image retrieval. Since color and edge orientation features are important visual information which help the human visual…

Computer Vision and Pattern Recognition · Computer Science 2019-09-24 Mohammad Rezaei , Ali Ahmadi , Navid Naderi

The $n=1$ photon ring is an important probe of black hole (BH) properties and will be resolved by the Black Hole Explorer (BHEX) for the first time. However, extraction of black hole parameters from observations of the $n=1$ subring is not…

High Energy Astrophysical Phenomena · Physics 2024-11-05 Joseph R. Farah , Jordy Davelaar , Daniel Palumbo , Michael D. Johnson , Jonathan Delgado

Imaging of the shadow around supermassive black hole (SMBH) horizon with a very long baseline interferometry (VLBI) is recognized recently as a powerful tool for experimental testing of Einstein's General relativity. The Event Horizon…

Quantitative phase imaging has become a topic of considerable interest in the microscopy community. We have recently described one such technique based on the use of a partitioned detection aperture, which can be operated in a single shot…

Optics · Physics 2015-10-20 Roman Barankov , Jean-Charles Baritaux , Jerome Mertz

The Event Horizon Telescope (EHT) aims to spatially resolve the silhouette (or shadow) of the supermassive black holes in the Galactic Centre (Sgr A$^\star$) and M87. The primary scientific objectives are to test general relativity in the…

High Energy Astrophysical Phenomena · Physics 2016-09-21 Tariq Blecher , Roger Deane , Gianni Bernardi , Oleg Smirnov

The very high spatial resolution provided by Adaptive Optics assisted spectroscopic observations at 8m-class telescopes (e.g. with SINFONI at the VLT) will allow to greatly increase the number of direct black hole (BH) mass measurements…

Astrophysics · Physics 2007-05-23 Guia Pastorini

Inference is crucial in modern astronomical research, where hidden astrophysical features and patterns are often estimated from indirect and noisy measurements. Inferring the posterior of hidden features, conditioned on the observed…

Instrumentation and Methods for Astrophysics · Physics 2022-06-29 He Sun , Katherine L. Bouman , Paul Tiede , Jason J. Wang , Sarah Blunt , Dimitri Mawet

The Event Horizon Telescope is preparing to produce time sequences of black hole images, or movies. In anticipation, we developed an autocorrelation technique to measure apparent rotational motion using the image-domain pattern speed…

High Energy Astrophysical Phenomena · Physics 2025-10-13 Nicholas S. Conroy , Michi Bauböck , Vedant Dhruv , Daeyoung Lee , Chi-kwan Chan , Abhishek V. Joshi , Ben Prather , Charles F. Gammie

The Event Horizon Telescope Consortium is on the verge to provide the first telescopic image of massive black holes SgrA* and M87* surrounded by accretion disks, at a resolution scale comparable to the size of their event horizons. Well…

High Energy Astrophysical Phenomena · Physics 2019-03-01 Jean-Pierre Luminet