scholarly journals Large-scale magnetic fields, curvature fluctuations, and the thermal history of the Universe

2007 ◽  
Vol 76 (10) ◽  
Author(s):  
Massimo Giovannini
Keyword(s):  
Magnetic Fields ◽  
Thermal History ◽  
Large Scale ◽  
History Of ◽  
The Universe

scholarly journals Using the morphology and magnetic fields of tailed radio galaxies as environmental probes

2014 ◽  
Vol 10 (S313) ◽  
pp. 321-326
Author(s):  
M. Johnston-Hollitt ◽  
S. Dehghan ◽  
L. Pratley
Keyword(s):  
Magnetic Fields ◽  
Large Scale ◽  
Large Population ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Local Conditions ◽  
History Of ◽  
Unique Source ◽  
The Universe ◽  
The Magnetic Field

AbstractBent-tailed (BT) radio sources have long been known to trace over densities in the Universe up to z ~ 1 and there is increasing evidence this association persists out to redshifts of 2. The morphology of the jets in BT galaxies is primarily a function of the environment that they have resided in and so BTs provide invaluable clues as to their local conditions. Thus, not only can samples of BT galaxies be used as signposts of large-scale structure, but are also valuable for obtaining a statistical measurement of properties of the intra-cluster medium including the presence of cluster accretion shocks & winds, and as historical anemometers, preserving the dynamical history of their surroundings in their jets. We discuss the use of BTs to unveil large-scale structure and provide an example in which a BT was used to unlock the dynamical history of its host cluster. In addition to their use as density and dynamical indicators, BTs are useful probes of the magnetic field on their environment on scales which are inaccessible to other methods. Here we discuss a novel way in which a particular sub-class of BTs, the so-called ‘corkscrew’ galaxies might further elucidate the coherence lengths of the magnetic fields in their vicinity. Given that BTs are estimated to make up a large population in next generation surveys we posit that the use of jets in this way could provide a unique source of environmental information for clusters and groups up to z = 2.

scholarly journals Magnetic Fields in Galaxy Clusters and in the Large-Scale Structure of the Universe

Galaxies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 142 ◽  
Author(s):  
Valentina Vacca ◽  
Matteo Murgia ◽  
Federica Govoni ◽  
Torsten Enßlin ◽  
Niels Oppermann ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Galaxy Clusters ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Quality Data ◽  
High Quality Data ◽  
History Of ◽  
The Universe ◽  
Detailed Picture

The formation and history of cosmic magnetism is still widely unknown. Significant progress can be made through the study of magnetic fields properties in the large-scale structure of the Universe: galaxy clusters, filaments, and voids of the cosmic web. A powerful tool to study magnetization of these environments is represented by radio observations of diffuse synchrotron sources and background or embedded radio galaxies. To draw a detailed picture of cosmic magnetism, high-quality data of these sources need to be used in conjunction with sophisticated tools of analysis.

scholarly journals Cosmic Microwave Background Anisotropy at Degree Angular Scales and the Thermal History of the Universe

1997 ◽  
Vol 480 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Paolo de Bernardis ◽  
Amedeo Balbi ◽  
Giancarlo De Gasperis ◽  
Alessandro Melchiorri ◽  
Nicola Vittorio
Keyword(s):  
Cosmic Microwave Background ◽  
Thermal History ◽  
Microwave Background ◽  
Cosmic Microwave Background Anisotropy ◽  
History Of ◽  
The Universe

scholarly journals A dark clue to seesaw and leptogenesis in a pseudo-Dirac singlet doublet scenario with (non)standard cosmology

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Partha Konar ◽  
Ananya Mukherjee ◽  
Abhijit Kumar Saha ◽  
Sudipta Show
Keyword(s):  
Dark Matter ◽  
Thermal History ◽  
Direct Detection ◽  
Critical Role ◽  
Mass Term ◽  
Baryon Asymmetry ◽  
Dark Sector ◽  
Lepton Asymmetry ◽  
History Of ◽  
The Universe

Abstract We propose an appealing alternative scenario of leptogenesis assisted by dark sector which leads to the baryon asymmetry of the Universe satisfying all theoretical and experimental constraints. The dark sector carries a non minimal set up of singlet doublet fermionic dark matter extended with copies of a real singlet scalar field. A small Majorana mass term for the singlet dark fermion, in addition to the typical Dirac term, provides the more favourable dark matter of pseudo-Dirac type, capable of escaping the direct search. Such a construction also offers a formidable scope to radiative generation of active neutrino masses. In the presence of a (non)standard thermal history of the Universe, we perform the detailed dark matter phenomenology adopting the suitable benchmark scenarios, consistent with direct detection and neutrino oscillations data. Besides, we have demonstrated that the singlet scalars can go through CP-violating out of equilibrium decay, producing an ample amount of lepton asymmetry. Such an asymmetry then gets converted into the observed baryon asymmetry of the Universe through the non-perturbative sphaleron processes owing to the presence of the alternative cosmological background considered here. Unconventional thermal history of the Universe can thus aspire to lend a critical role both in the context of dark matter as well as in realizing baryogenesis.

General Relativity and Cosmology

2020 ◽  
pp. 227-360
Author(s):  
P. J. E. Peebles
Keyword(s):  
Constant Velocity ◽  
Large Scale ◽  
Reference Frames ◽  
Physical Sciences ◽  
Inertial Frames ◽  
Moving Body ◽  
History Of ◽  
The Subject ◽  
Freely Moving ◽  
The Universe

This chapter discusses the development of physical sciences in seemingly chaotic ways, by paths that are at best dimly seen at the time. It refers to the history of ideas as an important part of any science, and particularly worth examining in cosmology, where the subject has evolved over several generations. It also examines the puzzle of inertia, which traces the connection to Albert Einstein's bold idea that the universe is homogeneous in the large-scale average called “cosmological principle.” The chapter cites Newtonian mechanics that defines a set of preferred motions in space, the inertial reference frames, by the condition that a freely moving body has a constant velocity. It talks about Ernst Mach, who argued that inertial frames are determined relative to the motion of the rest of the matter in the universe.

Philosophy of Cosmology

Philosophy ◽  
2019 ◽  
Author(s):  
Craig Fox ◽  
Marie Gueguen ◽  
Adam Koberinski ◽  
Chris Smeenk
Keyword(s):  
Large Scale ◽  
Central Area ◽  
Fundamental Physics ◽  
Philosophy Of Cosmology ◽  
History Of ◽  
Physical Cosmology ◽  
The Universe ◽  
Scientific Debates ◽  
Scientific Fields ◽  
General Philosophy Of Science

Physical cosmology, the study of the large-scale structure of the universe and its evolution, has become a central area of research in fundamental physics. Theoretical and observational developments have led to acceptance of a “standard model” describing the history of the universe in impressive detail. These developments raise a number of challenging foundational questions that have stimulated the emerging field of philosophy of cosmology. Many of these questions are closely tied to discussions in general philosophy of science and philosophy of physics, whereas others are distinctive to the field. This bibliography aims to provide an orientation for both kinds of questions. As philosophy of cosmology is an emerging field, the literature in this area is sparse. Hence this bibliography includes two kinds of references that do not explicitly address philosophy of cosmology. First, it identifies several philosophical papers regarding other scientific fields, with the thought that these will inform discussions of parallel issues in cosmology. Second, it includes several references to the scientific literature, to provide philosophers with a useful orientation to contemporary scientific debates.

scholarly journals Some Critical Remarks on the Inflationary Universe Concept

1988 ◽  
Vol 130 ◽  
pp. 63-65
Author(s):  
Gerhard Börner
Keyword(s):  
Large Scale ◽  
Higgs Field ◽  
Quantitative Model ◽  
Time Interval ◽  
Inflationary Universe ◽  
Fundamental Particle ◽  
The Standard Model ◽  
History Of ◽  
Simple Change ◽  
The Universe

The basic idea of inflation in cosmology is very simple: It is the assumption that the expansion factor R(t) of a Friedmann-Lemaltre cosmological model grows exponentially during a brief time interval in the very early universe. The phase of exponential growth is followed by a thermalizatlon stage and a subsequent “normal” evolution R(t)∼vt. This “Inflationary expansion“ can help to solve cosmological puzzles inherent in the standard model - such as the large-scale flatness, the horizon structure, the numerical value of the entropy in a comoving volume [for a review see Brandenberger 1985]. To turn this romantic idea of inflation into a quantitative model requires still a lot of work: The simple change in the thermal history of the universe must be derived from a fundamental particle theory. The models proposed so far do not inspire much confidence. In the following a few difficulties of the Higgs field idea, especially the Coleman-Weinberg formalism will be pointed out (section 1). In section 2 some problems connected with the investigation of initially strongly anisotropic or Inhomogeneous cosmological models will be mentioned.

scholarly journals Magnetism in the Early Universe

2018 ◽  
Vol 14 (A30) ◽  
pp. 295-298
Author(s):  
Tina Kahniashvili ◽  
Axel Brandenburg ◽  
Arthur Kosowsky ◽  
Sayan Mandal ◽  
Alberto Roper Pol
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Gravitational Waves ◽  
Early Universe ◽  
Large Scale ◽  
Direct Detection ◽  
Correlation Lengths ◽  
Cosmological Scenario ◽  
Expansion Of The Universe ◽  
The Universe

AbstractBlazar observations point toward the possible presence of magnetic fields over intergalactic scales of the order of up to ∼1 Mpc, with strengths of at least ∼10−16 G. Understanding the origin of these large-scale magnetic fields is a challenge for modern astrophysics. Here we discuss the cosmological scenario, focussing on the following questions: (i) How and when was this magnetic field generated? (ii) How does it evolve during the expansion of the universe? (iii) Are the amplitude and statistical properties of this field such that they can explain the strengths and correlation lengths of observed magnetic fields? We also discuss the possibility of observing primordial turbulence through direct detection of stochastic gravitational waves in the mHz range accessible to LISA.

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