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Related papers: An Event Horizon Imager (EHI) Mission Concept Util…

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We discuss the capability of a third-generation ground-based detector such as the Einstein Telescope (ET) to enhance our astrophysical knowledge through detections of gravitational waves emitted by binaries including intermediate-mass and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Jonathan R. Gair , Ilya Mandel , M. Coleman Miller , Marta Volonteri

Extreme mass ratio inspirals (EMRIs), where a small compact object inspiralls onto a supermassive black hole, are excellent sources for the space-based laser interferometer gravitational wave (GW) detectors. The presence of dark matter…

General Relativity and Quantum Cosmology · Physics 2024-01-10 Chao Zhang , Guoyang Fu , Ning Dai

Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime. We consider a wide range of well-motivated deviations from classical…

No. All theoretical predictions for the observational appearance of an accreting supermassive black hole, as measured interferometrically by a sparse Earth-sized array at current observation frequencies, are sensitive to many untested…

High Energy Astrophysical Phenomena · Physics 2021-01-20 Samuel E. Gralla

The Event Horizon Telescope (EHT) collaboration has recently released the first image of a black hole (BH), opening a new window onto tests of general relativity in the strong field regime. In this paper, we derive constraints on the nature…

General Relativity and Quantum Cosmology · Physics 2020-02-24 Cosimo Bambi , Katherine Freese , Sunny Vagnozzi , Luca Visinelli

The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed next generation multi-wavelength survey mission. The primary instrument is a High Energy telescope (HET) that conducts the deepest survey for Gamma-ray Bursts (GRBs),…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 J. Hong , J. E. Grindlay , B. Allen , S. D. Barthelmy , G. K. Skinner , N. Gehrels , the EXIST HET Working Group

We investigate constraints on the distribution of dark matter in the neighbourhood of the Galactic centre that may eventually be attained with the high-resolution Event Horizon Telescope (EHT). The shadow of a black hole in vacuum is used…

Astrophysics of Galaxies · Physics 2013-08-15 Thomas Lacroix , Joseph Silk

The black hole spacetime is described by general relativity and characterized by two quantities: the black hole mass and spin. Black hole spin measurement requires information from the vicinity of the event horizon, which is spatially…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Kotaro Moriyama , Shin Mineshige , Mareki Honma , Kazunori Akiyama

A new image-reconstruction algorithm, PRIMO, applied to the interferometric data of the M87 black hole collected with the Event Horizon Telescope (EHT), resulted in an image that reached the native resolution of the telescope array. PRIMO…

Instrumentation and Methods for Astrophysics · Physics 2024-08-21 Dimitrios Psaltis , Feryal Ozel , Lia Medeiros , Tod R. Lauer

General relativity predicts that black hole images ought to display a bright, thin (and as-of-yet-unresolved) ring. This "photon ring" is produced by photons that explore the strong gravity of the black hole, flowing along trajectories that…

Black hole accretion is one of nature's most efficient energy extraction processes. When gas falls in, a significant fraction of its gravitational binding energy is either converted into radiation or flows outwards in the form of black…

In this paper, we provide a first physical interpretation for the Event Horizon Telescope (EHT)'s 2017 observations of Sgr A*. Our main approach is to compare resolved EHT data at 230 GHz and unresolved non-EHT observations from radio to…

High Energy Astrophysical Phenomena · Physics 2023-11-17 The Event Horizon Telescope Collaboration

This work proposes a methodology to test phenomenologically-motivated emission processes that account for the flux and polarization distribution and global structure of the 230 GHz sources imaged by the Event Horizon Telescope (EHT):…

Black hole images are theoretically predicted (under mild astrophysical assumptions) to display a stack of lensed "photon rings" that carry information about the underlying spacetime geometry. Despite vigorous efforts, no such ring has been…

General Relativity and Quantum Cosmology · Physics 2023-09-25 Alejandro Cárdenas-Avendaño , Alexandru Lupsasca

We propose a simple, analytic dual-cone accretion model for horizon scale images of the cores of Low-Luminosity Active Galactic Nuclei (LLAGN), including those observed by the Event Horizon Telescope (EHT). Our underlying model is of…

High Energy Astrophysical Phenomena · Physics 2025-11-27 Dominic O. Chang , Michael D. Johnson , Paul Tiede , Daniel C. M. Palumbo

There are now multiple direct probes of the region near black hole horizons, including direct imaging with the Event Horizon Telescope (EHT). As a result, it is now of considerable interest to identify what aspects of the underlying…

General Relativity and Quantum Cosmology · Physics 2023-11-06 Kiana Salehi , Avery Broderick , Boris Georgiev

We show that interferometry can be applied to study irregular, rapidly rotating structures, as are expected in the turbulent accretion flow near a black hole. Specifically, we analyze the lagged covariance between interferometric baselines…

Instrumentation and Methods for Astrophysics · Physics 2015-11-11 Michael D. Johnson , Abraham Loeb , Hotaka Shiokawa , Andrew A. Chael , Sheperd S. Doeleman

Context. The properties of the accretion flow surrounding the supermassive central black hole of the Galaxy, Sgr A*, will be scrutinized by the new-generation instrument GRAVITY and the Event Horizon Telescope (EHT). Developing fast,…

High Energy Astrophysical Phenomena · Physics 2019-04-17 F. H. Vincent , M. A. Abramowicz , A. A. Zdziarski , M. Wielgus , T. Paumard , G. Perrin , O. Straub

The goal of the Event Horizon Telescope (EHT) is to provide spatially resolved images of Sgr A*, the source associated with the Galactic Center black hole. Because Sgr A* varies on timescales short compared to an EHT observing campaign, it…

High Energy Astrophysical Phenomena · Physics 2017-09-06 Hotaka Shiokawa , Charles F. Gammie , Sheperd S. Doeleman

Extreme mass ratio inspirals (EMRIs) occur when stellar-mass compact objects begin a gravitational wave (GW) driven inspiral into massive black holes. EMRI waveforms can precisely map the surrounding spacetime, making them a key target for…

Astrophysics of Galaxies · Physics 2023-04-27 Ismail Qunbar , Nicholas C. Stone