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In previous work we have developed a general relativistic, magnetospheric eternally collapsing object (MECO) model for black hole candidates and shown that the model is consistent with broad band spectral and luminosity characteristics and…

Astrophysics · Physics 2008-08-12 Stanley L. Robertson , Darryl J. Leiter

Scattering of anisotropic radiation by atoms, ions or molecules is sufficient to generate linear polarization observable in stars and planets atmospheres, circumstellar environments, and in particular in the Sun's atmosphere. This kind of…

Solar and Stellar Astrophysics · Physics 2021-06-02 Saleh Qutub , Moncef Derouich , Badruddin Zaheer Ahmad

The radio source Sagittarius A* (Sgr A*) is believed to be a hot, inhomogeneous, magnetized plasma flowing near the event horizon of the 3 million solar mass black hole at the galactic center. At a distance of 8000 parsecs the black hole…

Astrophysics · Physics 2008-11-26 Scott C. Noble , Po Kin Leung , Charles F. Gammie , Laura G. Book

The Event Horizon Telescope (EHT) observations of Sgr\,A* resolved the shadow image and emission ring-like structure, which is associated to the photon ring of the supermassive black hole, at the galactic centre, revealing a diameter of…

High Energy Astrophysical Phenomena · Physics 2025-04-14 Milton Jair Santibañez-Armenta , Gustavo Magallanes-Guijón , Sergio Mendoza , Alejandro Cruz-Osorio

Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are recognized as the most promising magnetar candidates, as indicated by their energetic bursts and rapid spin-downs. It is expected that the strong magnetic field leaves…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Shan-Shan Weng , Ersin Gogus , Tolga Guver , Lin Lin

Pulsar scintillation can be used to measure small scale structure in the Galaxy, but little is known about the specific interstellar medium features that cause scintillation. We searched for interstellar medium counterparts to all…

High Energy Astrophysical Phenomena · Physics 2025-06-04 Ashley M. Stock , Marten H. van Kerkwijk

We study the alignments of satellite galaxies, and their anisotropic distribution, with respect to location and orientation of their host central galaxy in MassiveBlack-II and IllustrisTNG simulations. We find that: the shape of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 Ananth Tenneti , Thomas D. Kitching , Benjamin Joachimi , Tiziana Di Matteo

A model for homogeneous anisotropic incompressible turbulence is proposed. The model generalizes the GISS model of homogeneous isotropic turbulence; the generalization involves the solution of the GISS equations along a set of integration…

Astrophysics · Physics 2015-06-24 Kristof Petrovay

Interplanetary solar radio type III bursts provide the means for remotely studying and tracking energetic electrons propagating in the interplanetary medium. Due to the lack of direct radio source imaging, several methods have been…

For a decade now, evidence has accumulated that giant molecular clouds located within the central molecular zone of our Galaxy reflect X-rays coming from past outbursts of the supermassive black hole Sgr A*. However, the number of…

High Energy Astrophysical Phenomena · Physics 2018-02-28 Dimitri Chuard , Régis Terrier , Andrea Goldwurm , Maïca Clavel , Simona Soldi , Mark R. Morris , Gabriele Ponti , Michael Walls , Maria Chernyakova

We present results of a pilot observational wide-field VLBI campaign on probing scattering properties of the partly ionized interstellar medium towards the Galactic plane sky region between $28^\circ<l<36^\circ$ and $|b|<1^\circ$. This…

Relativistic jets are among the most fascinating objects in the Universe, and recent high-resolution Very Long Baseline Interferometric (VLBI) observations, including the Global mm-VLBI Array and the Event Horizon Telescope (EHT), are able…

High Energy Astrophysical Phenomena · Physics 2026-03-31 Felix Glaser , Christian M. Fromm , Luca Ricci , Yosuke Mizuno , Matthias Kadler , Karl Mannheim , Michael Janssen

The Event Horizon Telescope (EHT) recently released an image of the supermassive black hole Sgr A* showing an angular shadow diameter $d_{sh}= 48.7 \pm 7\,\mu$as and Schwarzschild shadow deviation $\delta =…

General Relativity and Quantum Cosmology · Physics 2023-02-28 Sushant G. Ghosh , Misba Afrin

The magnetorotational instability is thought to play an important role in enabling accretion in sufficiently ionized astrophysical disks. The rate at which MRI-driven turbulence transports angular momentum is related to both the strength of…

Solar and Stellar Astrophysics · Physics 2015-10-26 Gareth C. Murphy , Martin E. Pessah

Turbulence in the weakly collisional intracluster medium of galaxies (ICM) is able to generate strong thermal velocity anisotropies in the ions (with respect to the local magnetic field direction), if the magnetic moment of the particles is…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-18 R. Santos-Lima , H. Yan , E. M. de Gouveia Dal Pino , A. Lazarian

Theoretical approaches to low-frequency magnetized turbulence in collisionless and weakly collisional astrophysical plasmas are reviewed. The proper starting point for an analytical description of these plasmas is kinetic theory, not fluid…

Astrophysics · Physics 2009-11-11 A. A. Schekochihin , S. C. Cowley , W. Dorland

Velocity anisotropy induced by MHD turbulence is investigated using computational simulations and molecular line observations of the Taurus molecular cloud. A new analysis method is presented to evaluate the degree and angle of velocity…

Astrophysics · Physics 2009-11-13 Mark Heyer , Hao Gong , Eve Ostriker , Christopher Brunt

Multi-wavelength monitoring of Sgr A* flaring activity confirms the presence of embedded structures within the disk on size scales commensurate with the innermost accretion region, matching size scales that are derived from observed light…

High Energy Astrophysical Phenomena · Physics 2015-11-10 E M Howard

Very strong evidence suggests that Sagittarius A*, a compact radio source at the center of the Milky Way, marks the position of a super massive black hole. The proximity of Sgr A* in combination with its mass makes its apparent event…

Astrophysics of Galaxies · Physics 2009-06-23 Vincent L. Fish , Sheperd S. Doeleman

We present the highest resolution VLBI imaging observations of Sgr A* made at both 7 and 3.5 mm. These data reveal wavelength-dependent intrinsic sizes with an intrinsic emitting region at 3.5 mm of about 1 AU (at a distance of 8 kpc to the…

Astrophysics · Physics 2009-11-11 Zhi-Qiang Shen