scholarly journals Convection in Galaxy‐Cluster Plasmas Driven by Active Galactic Nuclei and Cosmic‐Ray Buoyancy

2004 ◽  
Vol 616 (1) ◽  
pp. 169-177 ◽  
Author(s):  
Benjamin D. G. Chandran
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Cluster ◽  
Galactic Nuclei ◽  
Cosmic Ray

scholarly journals Connecting turbulent velocities and magnetic fields in galaxy cluster simulations with active galactic nuclei jets

2021 ◽  
Vol 503 (1) ◽  
pp. 1327-1344
Author(s):  
K Ehlert ◽  
R Weinberger ◽  
C Pfrommer ◽  
V Springel
Keyword(s):  
Magnetic Fields ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Velocity Dispersion ◽  
Velocity Structure ◽  
Galaxy Cluster ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
Low Velocity ◽  
Active Galactic Nuclei Jets

ABSTRACT The study of velocity fields of the hot gas in galaxy clusters can help to unravel details of microphysics on small scales and to decipher the nature of feedback by active galactic nuclei (AGN). Likewise, magnetic fields as traced by Faraday rotation measurements (RMs) inform about their impact on gas dynamics as well as on cosmic ray production and transport. We investigate the inherent relationship between large-scale gas kinematics and magnetic fields through non-radiative magnetohydrodynamical simulations of the creation, evolution, and disruption of AGN jet-inflated lobes in an isolated Perseus-like galaxy cluster, with and without pre-existing turbulence. In particular, we connect cluster velocity measurements with mock RM maps to highlight their underlying physical connection, which opens up the possibility of comparing turbulence levels in two different observables. For single-jet outbursts, we find only a local impact on the velocity field, i.e. the associated increase in velocity dispersion is not volume-filling. Furthermore, in a setup with pre-existing turbulence, this increase in velocity dispersion is largely hidden. We use mock X-ray observations to show that at arcmin resolution, the velocity dispersion is therefore dominated by existing large-scale turbulence and is only minimally altered by the presence of a jet. For the velocity structure of central gas uplifted by buoyantly rising lobes, we find fast, coherent outflows with low velocity dispersion. Our results highlight that projected velocity distributions show complex structures, which pose challenges for the interpretation of observations.

scholarly journals Relativistic Jets from Active Galactic Nuclei

2019 ◽  
Vol 57 (1) ◽  
pp. 467-509 ◽  
Author(s):  
Roger Blandford ◽  
David Meier ◽  
Anthony Readhead
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Hot Spot ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
Major Influence ◽  
Buoyant Plumes ◽  
Normal Galaxies ◽  
Sphere Of Influence

The nuclei of most normal galaxies contain supermassive black holes, which can accrete gas through a disk and become active. These active galactic nuclei (AGNs) can form jets that are observed on scales from astronomical units to megaparsecs and from meter wavelengths to TeV energies. High-resolution radio imaging and multiwavelength/messenger campaigns are elucidating the conditions under which this happens. Evidence is presented that: ▪ Relativistic AGN jets are formed when the black hole spins and the the accretion disk is strongly magnetized, perhaps on account of gas accreting at high latitude beyond the black hole sphere of influence. ▪ AGN jets are collimated close to the black hole by magnetic stress associated with a disk wind. ▪ Higher-power jets can emerge from their galactic nuclei in a relativistic, supersonic, and proton-dominated state, and they terminate in strong, hot spot shocks; lower-power jets are degraded to buoyant plumes and bubbles. ▪ Jets may accelerate protons to EeV energies, which contribute to the cosmic ray spectrum and may initiate pair cascades that can efficiently radiate synchrotron γ-rays. ▪ Jets were far more common when the Universe was a few billion years old and black holes and massive galaxies were growing rapidly. ▪ Jets can have a major influence on their environments, stimulating and limiting the growth of galaxies. The observational prospects for securing our understanding of AGN jets are bright.

scholarly journals FM6: Summary of Session #5 on Accretion and Feedback in Active Galactic Nuclei

2015 ◽  
Vol 11 (A29B) ◽  
pp. 101-112
Author(s):  
Laura Brenneman
Keyword(s):  
Active Galactic Nuclei ◽  
Large Scale ◽  
Galaxy Cluster ◽  
Galactic Nuclei ◽  
Starburst Galaxies ◽  
X Ray ◽  
Large Scale Structures ◽  
Scale Structures

AbstractFocus Meeting 6 of the IAU 2015 Symposium centered around the topic of “X-ray Surveys of the Hot and Energetic Universe.” Within this two-day meeting seven sessions (31 total talks) were presented, whose topics included galaxy cluster physics and evolution, cluster cosmological studies, AGN demographics and X-ray binary populations, first quasars, accretion and feedback, large-scale structures, and normal and starburst galaxies. Herein, I summarize the results presented during session #5, which focused on AGN accretion and feedback. Six authors contributed their work to our session: Laura Brenneman, Kazushi Iwasawa, Massimo Gaspari, Michaela Hirschmann, Franz Bauer and Yuan Liu. I provide a brief introduction below, followed by the details of the presentations of each author in the order in which the presentations were given.

scholarly journals Ultra-high energy cosmic ray correlations with active galactic nuclei in the world dataset

JETP Letters ◽  
2012 ◽  
Vol 95 (10) ◽  
pp. 501-503
Author(s):  
G. I. Rubtsov ◽  
I. I. Tkachev ◽  
A. D. Dolgov
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
The World

scholarly journals IMPLICATIONS OF PC AND KPC JET ASYMMETRY TO THE COSMIC RAY ACCELERATION

2012 ◽  
Vol 08 ◽  
pp. 331-335
Author(s):  
NECTARIA A. B. GIZANI
Keyword(s):  
Cosmic Rays ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
Directional Asymmetry ◽  
X Ray ◽  
Radio Data ◽  
High Energies ◽  
Cosmic Ray Acceleration

We probe the role that the directional asymmetry, between relativistic outflows and kilo-parsec scale jets, play in the acceleration of cosmic rays. For this reason we use two powerful, nearby Active Galactic Nuclei (AGNs). These radio galaxies are atypical compared to the usual AGN as they contain ring-like features instead of hotspots. Our VLBI radio data have revealed a substantial misalignment between their small and large scale jets. Taking into account the overall information we have obtained about the AGNs themselves (VLA and VLBI radio data at 18 cm) and their clusters (X-ray observations) our study supports the present ideas of powerful radiogalaxies (radio quiet and radio loud) being sources of cosmic rays as well as their ability to accelarate the latter to ultra high energies.

scholarly journals HIGH ENERGY COSMIC RAYS, GAMMA RAYS AND NEUTRINOS FROM AGN

2008 ◽  
Vol 23 (24) ◽  
pp. 1991-1997 ◽  
Author(s):  
YUKIO TOMOZAWA
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Active Galactic Nuclei ◽  
Gamma Rays ◽  
Heavy Particle ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
High Energy ◽  
Neutrino Detectors ◽  
High Energy Cosmic Rays

The author reviews a model for the emission of high energy cosmic rays, gamma-rays and neutrinos from AGN (Active Galactic Nuclei) that he has proposed since 1985. Further discussion of the knee energy phenomenon of the cosmic ray energy spectrum requires the existence of a heavy particle with mass in the knee energy range. A possible method of detecting such a particle in the Pierre Auger Project is suggested. Also presented is a relation between the spectra of neutrinos and gamma-rays emitted from AGN. This relation can be tested by high energy neutrino detectors such as ICECUBE, the Mediterranean Sea Detector and possibly by the Pierre Auger Project.

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