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 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 Observational View of Magnetic Fields in Active Galactic Nuclei Jets

2016 ◽  
Vol 12 (S324) ◽  
pp. 149-156
Author(s):  
Talvikki Hovatta
Keyword(s):  
Black Hole ◽  
Magnetic Fields ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Short Review ◽  
Relativistic Jets ◽  
The Past ◽  
Emission Models ◽  
Active Galactic Nuclei Jets ◽  
The Magnetic Field

AbstractAccording to the currently favored picture, relativistic jets in active galactic nuclei (AGN) are launched in the vicinity of the black hole by magnetic fields extracting energy from the spinning black hole or the accretion disk. In the past decades, various models from shocks to magnetic reconnection have been proposed as the energy dissipation mechanism in the jets. This paper presents a short review on how linear polarization observations can be used to constrain the magnetic field structure in the jets of AGN, and how the observations can be used to constrain the various emission models.

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 Discovery of Helical Magnetic Fields in AGN, and CME and Ejection of Large-Scale Magnetic Fields from AGN

2003 ◽  
Vol 214 ◽  
pp. 303-308
Author(s):  
Han-Shu Chu ◽  
L. B. Baath ◽  
Fu-Jun Zhang ◽  
R. E. Spencer
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Direct Detection ◽  
Galactic Nuclei ◽  
Crucial Importance ◽  
Important Ingredient ◽  
Celestial Bodies ◽  
Helical Magnetic Field

Magnetic Fields are the crucial and most important ingredient involved in the processes of various violent activities in Active Galactic Nuclei and other celestial bodies. The generally accepted 2-sided symmetric-jets model of active galactic nuclei (AGN) does not include the magnetic fields. We present here the first direct detection of helical magnetic field in AGN, and the first direct detection of ejection of large scale magnetic fields from AGN. (CME) 2. The annular (helical) magnetic field is responsible for the collimation of the jet (through Pinch Effect) and may be of crucial importance for extraction of black hole rotational energy. 3. The CMEs are responsible for sporadic ejection of jet components in AGN, while the general accepted 2-sided jets pertain to the quiescent Jets. 4. Observations show that the CME with Asymmetric Jets can explain many phenomena and much of the morphological diversities in AGN.

scholarly journals CME and Ejection of Large Scale Magnetic Fields, Helical Magnetic Fields, and Intrinsically Asymmetric Jets - New Findings in AGN

1998 ◽  
Vol 164 ◽  
pp. 121-122
Author(s):  
H. S. Chu ◽  
F. J. Zhang ◽  
R. E. Spencer
Keyword(s):  
Magnetic Fields ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Direct Evidence ◽  
Galactic Nuclei ◽  
Relativistic Beaming ◽  
New Findings ◽  
Mass Ejection ◽  
Jet Structure ◽  
New Evidence

AbstractThe orthodox model of active galactic nuclei (AGN), as is generally accepted, is that of Rees. We have found an AGN (3C 147) which has a counter-jet much longer than the main jet. It also has an unusual sideways ejection from the nuclear region. Both of these and the 3-jet structure per se do not seem to conform with the general accepted model, and are also not explained by relativistic beaming effects. We speculate that this is due to coronal mass ejection (CME) in the accretion disk corona. Recently, we have found convincing new evidence that this is true. We have also found direct evidence of helical magnetic fields in the core region of 3C 147. These results may be of importance to the understanding of AGN.

scholarly journals 8.11. Magnetic avalanche model of mass supply in active galactic nuclei

1998 ◽  
Vol 184 ◽  
pp. 365-366
Author(s):  
T. Kuwabara ◽  
R. Matsumoto ◽  
K. Shibata
Keyword(s):  
Magnetic Fields ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Galactic Nuclei ◽  
Model Parameters ◽  
Initial State ◽  
Ionized Gas ◽  
Mhd Simulations ◽  
Weakly Ionized ◽  
Co Observations

We present the results of axisymmetric, two-dimentional magnetohydrodynamic (MHD) simulations of weakly ionized gas torus threaded by large scale vertical magnetic fields. The gas torus corresponds to the 100pc scale circumnuclear torus observed by HST in nearby AGNs (e.g. NGC4261) or 1010M⊙ circumnuclear gas found by CO observations in luminous IR galaxies and quasars (e.g. Scoville et al. 1991). The initial state of simulation is a constant angular momentum polytropic torus threaded by uniform vertical magnetic fields. The torus is assumed to be rotating in a static, spherical hot halo. The model parameters are Eth = vs02/(γvk02) = 5 ×10−3 and Eth = vA02/vK02 = 6.6×10−6 where γ is the adiabatic index and vs0 and va0 are the sound speed and the Alfvén speed at r = r0 respectively.

scholarly journals Understanding the origin of radio outflows in Seyfert galaxies using radio polarimetry

2019 ◽  
Vol 15 (S356) ◽  
pp. 247-251
Author(s):  
Biny Sebastian ◽  
Preeti Kharb ◽  
Christopher P. O’ Dea ◽  
Jack F. Gallimore ◽  
Stefi A. Baum ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Radio Emission ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Seyfert Galaxies ◽  
Starburst Galaxies ◽  
Galactic Magnetic Fields ◽  
5 Ghz

AbstractThe role of starburst winds versus active galactic nuclei (AGN) jets/winds in the formation of the kiloparsec scale radio emission seen in Seyferts is not yet well understood. In order to be able to disentangle the role of various components, we have observed a sample of Seyfert galaxies exhibiting kpc-scale radio emission suggesting outflows, along with a comparison sample of starburst galaxies, with the EVLA B-array in polarimetric mode at 1.4 GHz and 5 GHz. The Seyfert galaxy NGC 2639, shows highly polarized secondary radio lobes, not observed before, which are aligned perpendicular to the known pair of radio lobes. The additional pair of lobes represent an older epoch of emission. A multi-epoch multi-frequency study of the starburst-Seyfert composite galaxy NGC 3079, reveals that the jet together with the starburst superwind and the galactic magnetic fields might be responsible for the well-known 8-shaped radio lobes observed in this galaxy. We find that many of the Seyfert galaxies in our sample show bubble-shaped lobes, which are absent in the starburst galaxies that do not host an AGN.

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