Are There Rotation Measure Gradients Across Active Galactic Nuclei Jets?

Are There Rotation Measure Gradients Across Active Galactic Nuclei Jets?
Author: Gregory Benjamin Taylor
Publisher:
Total Pages: 5
Release: 2010
Genre: Active galactic nuclei
ISBN:

We report on multi-frequency polarimetry very long baseline interferometry observations of active galactic nuclei using the Very Long Baseline Array. These observations are used to construct images of the Faraday rotation measure (RM) in J1613+342, Mrk 501, 3C 371, and BL Lac. Despite having resolved the jets in total intensity and polarization for three of these sources no RM gradients are found. This is in contrast to the large fraction of sources with RM gradients now claimed in the literature and invoked as evidence in support of helical magnetic fields. We propose objective criteria for establishing what constitutes an RM gradient. Furthermore, although we note the absence of simple, monotonic gradients, comparison with simulations could reveal systematic changes in the RM that may be masked by a varying jet orientation.

How electrostatic fields generated by cosmic rays cause the expansion of the nearby universe

How electrostatic fields generated by cosmic rays cause the expansion of the nearby universe
Author: Antonio Codino
Publisher: Società Editrice Esculapio
Total Pages: 239
Release: 2022-12-15
Genre: Science
ISBN:

The positive electric charge transported by the cosmic radiation while migrating from the interiors of galaxy clusters toward the outer intergalactic space, slowly but inevitably, uncovers a negative electric charge of the same amount inside galaxy clusters, where it is mostly retained. Electrons constitute the negative electric charge inside galaxy clusters. The negative charge and the positive one of the overflowed cosmic nuclei in the intergalactic space cannot be neutralized due to the separating, huge distances. After time intervals of a few billion years, electrostatic repulsion among galaxy clusters initiates to contrast gravity and, at longer time spans, dominates. The electrostatic repulsion among galaxy clusters, which always store negative electric charges, determines in a few billion years, a general receding motion of cosmic matter, including smaller celestial bodies dragged in by galaxy clusters. It will be proved that the general receding motion of cosmic matter occurs with increasing velocities of galaxy clusters as far as the corresponding distances from the Earth augment.

Active Galactic Nuclei

Active Galactic Nuclei
Author: Volker Beckmann
Publisher: John Wiley & Sons
Total Pages: 390
Release: 2013-08-29
Genre: Science
ISBN: 352766680X

Active Galactic Nuclei This AGN textbook gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy distribution will be discussed, pointing out what can be observed in different wavebands. The different physical models are presented together with formula important for the understanding of AGN physics. Furthermore, the authors discuss the AGN with respect to its environment, host galaxy, feedback in galaxies and in clusters of galaxies, variability, etc. and finally the cosmological evolution of the AGN phenomenon. This book includes phenomena based on new results in the X-Ray and gamma-ray domain from new telescopes such as Chandra, XMM-Newton, the Fermi Gamma-Ray Space Telescope, and the VHE regime not mentioned so far in AGN books. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. From the contents: The observational picture of AGN Radiative processes The central engine AGN types and unification AGN through the electromagnetic spectrum AGN variability Environment Quasars and cosmology Formation, evolution and the ultimate fate of AGN What we do not know (yet)

The Physics and Evolution of Active Galactic Nuclei

The Physics and Evolution of Active Galactic Nuclei
Author: Hagai Netzer
Publisher: Cambridge University Press
Total Pages: 369
Release: 2013-09-16
Genre: Science
ISBN: 1107021510

A comprehensive introduction to the theory underpinning our study of active galactic nuclei and the ways we observe them.

The Formation and Disruption of Black Hole Jets

The Formation and Disruption of Black Hole Jets
Author: Ioannis Contopoulos
Publisher: Springer
Total Pages: 273
Release: 2014-11-10
Genre: Science
ISBN: 3319103563

This book reviews the phenomenology displayed by relativistic jets as well as the most recent theoretical efforts to understand the physical mechanisms at their origin. Relativistic jets have been observed and studied in Active Galactic Nuclei (AGN) for about half a century and are believed to be fueled by accretion onto a supermassive black hole at the center of the host galaxy. Since the first discovery of relativistic jets associated with so-called "micro-quasars" much more recently, it has seemed clear that much of the physics governing the relativistic outflows in stellar X-ray binaries harboring black holes and in AGN must be common, but acting on very different spatial and temporal scales. With new observational and theoretical results piling up every day, this book attempts to synthesize a consistent, unified physical picture of the formation and disruption of jets in accreting black-hole systems. The chapters in this book offer overviews accessible not only to specialists but also to graduate students and astrophysicists working in other areas. Covered topics comprise Relativistic jets in stellar systems Launching of AGN jets Parsec-scale AGN jets Kiloparsec-scale AGN jets Black hole magnetospheres Theory of relativistic jets The structure and dynamics of the inner accretion disk The origin of the jet magnetic field X-ray observations, phenomenology, and connection with theory

Cosmic Plasmas and Electromagnetic Phenomena

Cosmic Plasmas and Electromagnetic Phenomena
Author: Athina Meli
Publisher: MDPI
Total Pages: 264
Release: 2019-10-25
Genre: Science
ISBN: 3039214659

During the past few decades, plasma science has witnessed a great growth in laboratory studies, in simulations, and in space. Plasma is the most common phase of ordinary matter in the universe. It is a state in which ionized matter (even as low as 1%) becomes highly electrically conductive. As such, long-range electric and magnetic fields dominate its behavior. Cosmic plasmas are mostly associated with stars, supernovae, pulsars and neutron stars, quasars and active galaxies at the vicinities of black holes (i.e., their jets and accretion disks). Cosmic plasma phenomena can be studied with different methods, such as laboratory experiments, astrophysical observations, and theoretical/computational approaches (i.e., MHD, particle-in-cell simulations, etc.). They exhibit a multitude of complex magnetohydrodynamic behaviors, acceleration, radiation, turbulence, and various instability phenomena. This Special Issue addresses the growing need of the plasma science principles in astrophysics and presents our current understanding of the physics of astrophysical plasmas, their electromagnetic behaviors and properties (e.g., shocks, waves, turbulence, instabilities, collimation, acceleration and radiation), both microscopically and macroscopically. This Special Issue provides a series of state-of-the-art reviews from international experts in the field of cosmic plasmas and electromagnetic phenomena using theoretical approaches, astrophysical observations, laboratory experiments, and state-of-the-art simulation studies.