High energy neutrino sources

1994 ◽  
Vol 346 (1678) ◽  
pp. 93-98 ◽  
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Cosmic Strings ◽  
Galactic Nuclei ◽  
High Energy ◽  
Big Bang ◽  
The Past ◽  
The Earth ◽  
The Big Bang ◽  
Bright Phase

High energy cosmic neutrinos can be produced by protons and nuclei accelerated in cosmic sources (‘acceleration neutrinos) as well as by relic Big Bang particles, cosmic strings, etc. (neutrinos of non-acceleration origin). The most promising ‘acceleration’ sources of neutrinos are supernovae in our Galaxy and active galactic nuclei (AGN). Detectable diffuse fluxes of ‘ acceleration ’ neutrinos can be produced by AGN and during the ‘bright phase’ of galaxy evolution. During the past few years it has been realized that the detectable flux of high energy neutrinos can be also produced by the relic Big Bang particles. The possible sources are annihilation of the neutralinos accumulated inside the Earth and the Sun, decay of neutralinos (due to the weak breaking of R-parity), and the decay of exotic long-lived particles from the Big Bang.

scholarly journals QUARK MATTER AND NUCLEAR COLLISIONS A BRIEF HISTORY OF STRONG INTERACTION THERMODYNAMICS

2012 ◽  
Vol 21 (08) ◽  
pp. 1230006 ◽  
Author(s):  
HELMUT SATZ
Keyword(s):  
High Energy ◽  
Big Bang ◽  
Nuclear Collision ◽  
Strong Interactions ◽  
Extreme Temperatures ◽  
Nuclear Collisions ◽  
The Past ◽  
History Of ◽  
The Big Bang ◽  
Theory And Experiment

The past 50 years have seen the emergence of a new field of research in physics, the study of matter at extreme temperatures and densities. The theory of strong interactions, quantum chromodynamics (QCD), predicts that in this limit, matter will become a plasma of deconfined quarks and gluons — the medium which made up the early universe in the first 10 microseconds after the Big Bang. High energy nuclear collisions are expected to produce short-lived bubbles of such a medium in the laboratory. I survey the merger of statistical QCD and nuclear collision studies for the analysis of strongly interacting matter in theory and experiment.

scholarly journals Sources of X-rays from galaxies

2011 ◽  
Vol 7 (S284) ◽  
pp. 183-192
Author(s):  
Q. Daniel Wang
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Supernova Remnants ◽  
Large Scale ◽  
Formation Rate ◽  
Galactic Nuclei ◽  
High Energy ◽  
High Mass ◽  
X Rays ◽  
X Ray

AbstractGalactic X-ray emission is a manifestation of various high-energy phenomena and processes. The brightest X-ray sources are typically accretion-powered objects: active galactic nuclei and low- or high-mass X-ray binaries. Such objects with X-ray luminosities of ≳ 1037 ergs s−1 can now be detected individually in nearby galaxies. The contributions from fainter discrete sources (including cataclysmic variables, active binaries, young stellar objects, and supernova remnants) are well correlated with the star formation rate or stellar mass of galaxies. The study of discrete X-ray sources is essential to our understanding of stellar evolution, dynamics, and end-products as well as accretion physics. With the subtraction of the discrete source contributions, one can further map out truly diffuse X-ray emission, which can be used to trace the feedback from active galactic nuclei, as well as from stars, both young and old, in the form of stellar winds and supernovae. The X-ray emission efficiency, however, is only about 1% of the energy input rate of the stellar feedback alone. The bulk of the feedback energy is most likely gone with outflows into large-scale galactic halos. Much is yet to be investigated to comprehend the role of such outflows in regulating the ecosystem, hence the evolution of galaxies. Even the mechanism of the diffuse X-ray emission remains quite uncertain. A substantial fraction of the emission cannot arise directly from optically-thin thermal plasma, as commonly assumed, and most likely originates in its charge exchange with neutral gas. These uncertainties underscore our poor understanding of the feedback and its interplay with the galaxy evolution.

scholarly journals Plasma model of microwave background and primordial elements: an alternative to the big bang

1988 ◽  
Vol 6 (3) ◽  
pp. 457-469 ◽  
Author(s):  
Eric J. Lerner
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Formation ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
Big Bang ◽  
Background Intensity ◽  
Plasma Model ◽  
Microwave Background ◽  
Extended Radio ◽  
The Big Bang

A plasma model of the origin of the light elements and the microwave background is presented. In contrast to the conventional Big Bang hypothesis, the model assumes that helium, deuterium and the microwave background were all generated by massive stars in the early stages of galaxy formation. The microwave background is scattered and isotropized by multi-GeV electrons trapped in the jets emitted by active galactic nuclei. The model produces reasonable amounts of heavy elements, accurately predicts the gamma-ray background intensity and spectrum, and explains the statistics of quasars, compact and extended radio sources.

scholarly journals Diffuse gamma-ray emission from the Galactic center and implications of its past activities

2016 ◽  
Vol 11 (S322) ◽  
pp. 214-217
Author(s):  
Yutaka Fujita ◽  
Shigeo S. Kimura ◽  
Kohta Murase
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Center ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
High Energy ◽  
Accretion Flows ◽  
The Past ◽  
Sagittarius A ◽  
Sgr A

AbstractIt has been indicated that low-luminosity active galactic nuclei (LLAGNs) are accelerating high-energy cosmic-ray (CR) protons in their radiatively inefficient accretion flows (RIAFs). If this is the case, Sagittarius A* (Sgr A*) should also be generating CR protons, because Sgr A* is a LLAGN. Based on this scenario, we calculate a production rate of CR protons in Sgr A* and their diffusion in the central molecular zone (CMZ) around Sgr A*. The CR protons diffusing in the CMZ create gamma-rays through pp interaction. We show that the gamma-ray luminosity and spectrum are consistent with observations if Sgr A* was active in the past.

scholarly journals On the acceleration of ultra-high-energy cosmic rays

2008 ◽  
Vol 366 (1884) ◽  
pp. 4417-4428 ◽  
Author(s):  
Federico Fraschetti
Keyword(s):  
Cosmic Rays ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
High Energy ◽  
New Physics ◽  
Acceleration Process ◽  
Tennis Ball ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
The Past

Ultra-high-energy cosmic rays (UHECRs) hit the Earth's atmosphere with energies exceeding 10 18  eV. This is the same energy as carried by a tennis ball moving at 100 km h −1 , but concentrated on a subatomic particle. UHECRs are so rare (the flux of particles with E >10 20  eV is 0.5 km −2 per century) that only a few such particles have been detected over the past 50 years. Recently, the HiRes and Auger experiments have reported the discovery of a high-energy cut-off in the UHECR spectrum, and Auger has found an apparent clustering of the highest energy events towards nearby active galactic nuclei. Consensus is building that the highest energy particles are accelerated within the radio-bright lobes of these objects, but it remains unclear how this actually happens, and whether the cut-off is due to propagation effects or reflects an intrinsically physical limitation of the acceleration process. The low event statistics presently allows for many different plausible models; nevertheless observations are beginning to impose strong constraints on them. These observations have also motivated suggestions that new physics may be implicated. We present a review of the key theoretical and observational issues related to the processes of propagation and acceleration of UHECRs and proposed solutions.

scholarly journals Conference Summary

2013 ◽  
Vol 9 (S304) ◽  
pp. 426-431 ◽  
Author(s):  
David B. Sanders
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Gamma Rays ◽  
Time Domain ◽  
Large Scale ◽  
Galactic Nuclei ◽  
The Past ◽  
Multi Wavelength ◽  
Objective Prism

AbstractThis conference on “Multi-wavelength AGN Surveys and Studies” has provided a detailed look at the explosive growth over the past decade, of available astronomical data from a growing list of large scale sky surveys, from radio-to-gamma rays. We are entering an era were multi-epoch (months to weeks) surveys of the entire sky, and near-instantaneous follow-up observations of variable sources, are elevating time-domain astronomy to where it is becoming a major contributor to our understanding of Active Galactic Nuclei (AGN). While we can marvel at the range of extragalactic phenomena dispayed by sources discovered in the original “Markarian Survey” – the first large-scale objective prism survey of the Northern Sky carried out at the Byurakan Astronomical Observtory almost a half-century ago – it is clear from the talks and posters presented at this meeting that the data to be be obtained over the next decade will be needed if we are to finally understand which phase of galaxy evolution each Markarian Galaxy represents.

scholarly journals КВАЗАРИ І РЕГЕНЕРАЦІЯ ВОДНЮ. ЧАСТИНА 2.

2019 ◽  
pp. 190-201
Author(s):  
Анатолий Николаевич Нарожный
Keyword(s):  
Active Galactic Nuclei ◽  
Indirect Evidence ◽  
Galactic Nuclei ◽  
Big Bang ◽  
Residual Hydrogen ◽  
The Galaxy ◽  
Intergalactic Space ◽  
Galactic Astronomy ◽  
The Big Bang ◽  
The Universe

Further consequences of the mechanisms of hydrogen regeneration, which are realized in large galaxies during the period of activity of their nuclei, are considered. In addition to the indirect evidence presented in the first part and related to the work of the structures forming the jets, this part of the article considers direct evidence of the existence of these processes in galaxies. The evidence given is based on emissions of regenerated hydrogen into galactic and intergalactic space, as shown by astronomical observations of the Galaxy and its closest surroundings. Evidence is also found among the general observational data of intergalactic astronomy, the origin of which is well explained in the framework of the approach presented. However, these data are traditionally viewed through the prism of the dominant concept, that is, they are interpreted as residual hydrogen, which appeared from the Big Bang. Among the results of galactic astronomy there are data showing the possible contribution of the processes under consideration to the formation of the observable structure of the Milky Way, as well as their involvement in the organization of its satellite galaxies. The criterion is given, according to which galactic gas clouds and star groups can be distinguished, organized from the galaxy's own matter during the period of activity of its nucleus. Using the example of a spiral galaxy, it is suggested that the active galactic nuclei might be involved in the formation of the morphology of the galaxy. It is concluded that the central supermassive object in the period of its activity, performs its main galactic function - carries out the processing of waste of stars in the galaxy. This inverse process closes the chain of the continuous life cycle of the galaxy, which consists of two interrelated processes. The first process is the continuous burning of hydrogen in the stars, and the second is the episodic activity of the galactic nucleus, as a result of which hydrogen is recovered from the "waste", necessary to support direct stellar processes. One more process joins these two processes - the process of returning the energy expended by baryonic matter to electromagnetic radiation. It is realized through the dark component of matter. The main conclusion is made - the Universe as a system is well organized and self-sufficient for its eternal existence, and it does not need any external motivation.

The Bakerian Lecture, 1982: Galaxies and their nuclei

1985 ◽  
Vol 400 (1819) ◽  
pp. 183-218 ◽  
Keyword(s):  
Black Holes ◽  
Galactic Nuclei ◽  
High Energy ◽  
Big Bang ◽  
Stellar Structure ◽  
Kerr Metric ◽  
Galactic Centre ◽  
The Galaxy ◽  
Nearby Galaxies ◽  
The Big Bang

This lecture briefly reviews current ideas on some key problems in extragalactic physics. Our understanding of galaxies and how they evolve is still tentative and fragmentary – perhaps at the same level as the study of stellar structure several decades ago. The ‘seeds’ from which galaxies formed were small-amplitude fluctuations imprinted during the initial high-energy phases of the Big Bang; but it is conventional physics - gas dynamics, atomic physics and Newtonian gravity - that determines their characteristic sizes and shapes. Quantitative modelling of galactic evolution is impeded by our poor understanding of how stars form from protogalactic gas. Another stumbling block has been the realization that 90% of the gravitating material in galaxies is in some ‘hidden’ form: the conspicuous stars and gas are merely ‘sediment’ in a potential well ten times larger contributed by material of unknown nature. The hidden mass could be small faint stars or the collapsed remnants of massive stars; alternatively, it could be some species of particle surviving from the Big Bang. Some galaxies harbour, in their centres, ‘engines’ more powerful than the entire integrated output of their ca 10 11 constituent stars. Extreme instances of this phenomenon are the quasars – galactic nuclei that flare up to outshine the rest of the galaxy. Galaxies sometimes eject wellcollimated jets of (possibly electron-positron) plasma, flowing at almost the speed of light. These jets, transporting an energy flux that may amount to an entire galactic luminosity, propagate for up to 10 6 light years; their interaction with the external medium is manifested in the intense synchrotron radiation from strong radio sources. Active galactic nuclei probably involve spinning black holes of 10 8 M ⊙ (described in Einstein’s theory by the Kerr metric) created by a runaway gravitational collapse. The luminosity and the plasma outflow could be energized by infall of surrounding material, or by the rotational energy of the holes, which can be extracted via electromagnetic torques. Massive black holes may lurk quiescent in the centres of several nearby galaxies, and even at our own Galactic Centre.

The First Galaxies in the Universe

2013 ◽  
Author(s):  
Abraham Loeb ◽  
Steven R. Furlanetto
Keyword(s):  
Galaxy Evolution ◽  
Big Bang ◽  
First Stars ◽  
Distant Galaxies ◽  
Formation And Evolution ◽  
Early Galaxies ◽  
First Galaxies ◽  
Large Telescopes ◽  
New Generation ◽  
The Big Bang

This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies. The book starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more.

scholarly journals Planck Neutrinos as Ultra High Energy Cosmic Rays

2020 ◽  
Vol 29 (1) ◽  
pp. 40-46
Author(s):  
Dmitri L. Khokhlov
Keyword(s):  
Black Holes ◽  
Cosmic Rays ◽  
Standard Model ◽  
Active Galactic Nuclei ◽  
Planck Scale ◽  
Galactic Nuclei ◽  
High Energy ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
The Standard Model

AbstractThe studied conjecture is that ultra high energy cosmic rays (UHECRs) are hypothetical Planck neutrinos arising in the decay of the protons falling onto the gravastar. The proton is assumed to decay at the Planck scale into positron and four Planck neutrinos. The supermassive black holes inside active galactic nuclei, while interpreted as gravastars, are considered as UHECR sources. The scattering of the Planck neutrinos by the proton at the Planck scale is considered. The Planck neutrinos contribution to the CR events may explain the CR spectrum from 5 × 1018 eV to 1020 eV. The muon number in the Planck neutrinos-initiated shower is estimated to be larger by a factor of 3/2 in comparison with the standard model that is consistent with the observational data.

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