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On The Possible Association Of Ultra High Energy Cosmic Rays With Nearby Active Galaxies
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Book Synopsis On the Possible Association of Ultra High Energy Cosmic Rays with Nearby Active Galaxies by :
Download or read book On the Possible Association of Ultra High Energy Cosmic Rays with Nearby Active Galaxies written by and published by . This book was released on 2008 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of cosmic rays (CRs) with energies>57 EeV that suggests a correlation with the positions of active galactic nuclei (AGN) located within H"5 Mpc. However, this analysis does not take into account AGN morphology. A detailed study of the sample of AGN whose positions correlate with the CR events shows that most of them are classified as Seyfert 2 and low-ionization nuclear emission-line region (LINER) galaxies which do not differ from other local AGN of the same types. Therefore, the claimed correlation between the CR events observed by the Pierre Auger Observatory and local active galaxies should be considered as resulting from a chance coincidence, if the production of the highest energy CRs is not episodic in nature, but operates in a single object on long (e"Myr) timescales. Additionally, most of the selected sources do not show significant jet activity, and hence--in the framework of the jet paradigm--there are no reasons for expecting them to accelerate CRs up to the highest energies, H"02° eV, at all. If the extragalactic magnetic fields and the sources of these CRs are coupled with matter, it is possible that the deflection angle is larger than expected in the case of a uniform source distribution due to effectively larger fields. A future analysis has to take into account AGN morphology and may yield a correlation with a larger deflection angle and/or more distant sources. We further argue that Cen A alone could be associated with at least 4 events due to its large radio extent, and Cen B can be associated with more than 1 event due to its proximity to the Galactic plane and, correspondingly, the stronger Galactic magnetic field the ultra high energy CRs (UHECRs) encounter during propagation. If the UHECRs associated with these events are indeed accelerated by Cen A and Cen B, their deflection angles may provide information on the structure of the magnetic field in the direction of these putative sources. Future -ray observations (by, e.g., Gamma-Ray Large Area Space Telescope [GLAST], High Energy Stereoscopic System [HESS]) may provide additional clues to the nature of the accelerators of the UHECRs in the local Universe.
Book Synopsis Very High Energy Phenomena in the Universe by : Yannick Giraud-Héraud
Download or read book Very High Energy Phenomena in the Universe written by Yannick Giraud-Héraud and published by Atlantica Séguier Frontières. This book was released on 1997 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Correlation of the Highest-energy Cosmic Rays with the Positions of Nearby Active Galactic Nuclei by :
Download or read book Correlation of the Highest-energy Cosmic Rays with the Positions of Nearby Active Galactic Nuclei written by and published by . This book was released on 2007 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [1]. The correlation has maximum significance for cosmic rays with energy greater than (almost equal to) 6 x 1019 eV and AGN at a distance less than (almost equal to) 75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified a priori, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest energies originate from extra-galactic sources close enough so that their flux is not significantly attenuated by interaction with the cosmic background radiation (the Greisen-Zatsepin-Kuzmin effect). The angular scale of the correlation observed is a few degrees, which suggests a predominantly light composition unless the magnetic fields are very weak outside the thin disk of our galaxy. Our present data do not identify AGN as the sources of cosmic rays unambiguously, and other candidate sources which are distributed as nearby AGN are not ruled out. We discuss the prospect of unequivocal identification of individual sources of the highest-energy cosmic rays within a few years of continued operation of the Pierre Auger Observatory.
Book Synopsis Clustering Properties of Ultrahigh Energy Cosmic Rays and the Search for Their Astrophysical Sources by :
Download or read book Clustering Properties of Ultrahigh Energy Cosmic Rays and the Search for Their Astrophysical Sources written by and published by . This book was released on 2007 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The arrival directions of ultrahigh energy cosmic rays (UHECRs) may show anisotropies on all scales, from just above the experimental angular resolution up to medium scales and dipole anisotropies. We find that a global comparison of the two-point auto-correlation function of the data with the one of catalogues of potential sources is a powerful diagnostic tool. In particular, this method is far less sensitive to unknown deflections in magnetic fields than cross-correlation studies while keeping a strong discrimination power among source candidates. We illustrate these advantages by considering ordinary galaxies, gamma ray bursts and active galactic nuclei as possible sources. Already the sparse publicly available data suggest that the sources of UHECRs may be a strongly clustered sub-sample of galaxies or of active galactic nuclei. We present forecasts for various cases of source distributions which can be checked soon by the Pierre Auger Observatory.
Book Synopsis Physics and Astrophysics of Ultra High Energy Cosmic Rays by : M. Lemoine
Download or read book Physics and Astrophysics of Ultra High Energy Cosmic Rays written by M. Lemoine and published by Springer Science & Business Media. This book was released on 2001-12-14 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International School on Physics and Astrophysics of Ultra High Energy Cosmic Rays (UHECR2000) was held at the Observatoire de Paris–Meudon on June 26-29, 2000. This was the ?rst international school speci?cally dedicated to ultra high energy cosmic rays. Its aim was to familiarize with and attract students, physicists and astronomers into this quickly developing newresearch ?eld. The mysterious and currently unknown origin of the most energetic par- cles observed in Nature has triggered in recent years theoretical speculations ranging from electromagnetic acceleration to as yet undiscovered physics - yond the Standard Model. It has also lead to the development of several new detection concepts and experimental projects, some of which are currently - der construction. By its nature, the ?eld of ultra high energy cosmic rays is therefore highly interdisciplinary and borrows from astrophysics and cosmology, via particle physics, to experimental physics and observational astronomy. One main aspect of the school was to emphasize and take advantage of this interd- ciplinarity. The lectures were grouped into subtopics and are reproduced in this volume in the following order: After a general introductory lecture on cosmic rays follow two contributions on experimental detection techniques, followed by three lectures on acceleration in astrophysical objects. The next four contri- tions cover all major aspects of propagation and interactions of ultra high energy radiation, including speculative issues such as newinteractions.
Book Synopsis Acceleration and Propagation of Cosmic Rays in High-Metallicity Astrophysical Environments by : Ana Laura Müller
Download or read book Acceleration and Propagation of Cosmic Rays in High-Metallicity Astrophysical Environments written by Ana Laura Müller and published by Springer Nature. This book was released on 2022-10-01 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis addresses the feasibility of the production of ultra-high-energy cosmic rays in starburst galaxies and active galactic nuclei. These astrophysical objects were theoretically proposed as candidate sources a long time ago. Nevertheless, the interest in them has been recently renewed due to the observational data collected by the Pierre Auger Observatory and the Telescope Array. In this work, a comprehensive review of the current status of the research on cosmic rays accelerators is provided, along with a summary of the principal concepts needed to connect these relativistic particles with electromagnetic and neutrino observations in the multi-messenger era. On one hand, the hypothesis of accelerating particles with energies above 1018 eV in starburst superwinds is carefully revisited, taking into account the constraints imposed by the most recent electromagnetic observations. On the other hand, an alternative new model for the gamma emission of the nearby active galaxy NGC 1068 is presented. The implications of the results of these studies are discussed in terms of the contemporary observatories and prospects for future experiments are offered.
Book Synopsis Active Galactic Nuclei: Sources for Ultra High Energy Cosmic Rays? by : Peter L. Biermann
Download or read book Active Galactic Nuclei: Sources for Ultra High Energy Cosmic Rays? written by Peter L. Biermann and published by . This book was released on 2010 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Update on the Correlation of the Highest Energy Cosmic Rays with Nearby Extragalactic Matter by :
Download or read book Update on the Correlation of the Highest Energy Cosmic Rays with Nearby Extragalactic Matter written by and published by . This book was released on 2010 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuzmin energy threshold, 6 x 1019 eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1{sup o} from the position of an active galactic nucleus within 75 Mpc (using the Veron-Cetty and Veron 12th catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (386{sup +7})%, compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of (6913{sup +11})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.
Book Synopsis Very High Energy Cosmic Gamma Radiation by : Felix A. Aharonian
Download or read book Very High Energy Cosmic Gamma Radiation written by Felix A. Aharonian and published by World Scientific. This book was released on 2004 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma ray astronomy, the branch of high energy astrophysics that studies the sky in energetic ?-ray photons, is destined to play a crucial role in the exploration of nonthermal phenomena in the Universe in their most extreme and violent forms. The great potential of this discipline offers impressive coverage of many OC hot topicsOCO of modern astrophysics and cosmology, such as the origin of galactic and extragalactic cosmic rays, particle acceleration and radiation processes under extreme astrophysical conditions, and the search for dark matter."
Book Synopsis Correlation of the Highest Energy Cosmic Rays with Nearby Extragalactic Objects by :
Download or read book Correlation of the Highest Energy Cosmic Rays with Nearby Extragalactic Objects written by and published by . This book was released on 2007 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrate that there is a correlation between the arrival directions of cosmic rays with energy above (almost equal to) 6 x 1019 eV and the positions of active galactic nuclei (AGN) lying within (almost equal to) 75 Mpc. We reject the hypothesis of an isotropic distribution of these cosmic rays at over 99% confidence level from a prescribed a priori test. The correlation we observe is compatible with the hypothesis that the highest energy particles originate from nearby extragalactic sources whose flux has not been significantly reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.
Book Synopsis On the Origin of Ultra High Energy Cosmic Rays II by :
Download or read book On the Origin of Ultra High Energy Cosmic Rays II written by and published by . This book was released on 2011 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: We show that accretion disks around Active Galactic Nuclei (AGNs) could account for the enormous power in observed ultra high energy cosmic rays ≈102° eV (UHEs). In our model, cosmic rays are produced by quasi-steady acceleration of ions in magnetic structures previously proposed to explain jets around Active Galactic Nuclei with supermassive black holes. Steady acceleration requires that an AGN accretion disk act as a dynamo, which we show to follow from a modified Standard Model in which the magnetic torque of the dynamo replaces viscosity as the dominant mechanism accounting for angular momentum conservation during accretion. A black hole of mass M{sub BH} produces a steady dynamo voltage V ∝ √M{sub BH} giving V ≈ 102° volts for M{sub BH} ≈ 108 solar masses. The voltage V reappears as an inductive electric field at the advancing nose of a dynamo-driven jet, where plasma instability inherent in collisionless runaway acceleration allows ions to be steadily accelerated to energies ≈ V, finally ejected as cosmic rays. Transient events can produce much higher energies. The predicted disk radiation is similar to the Standard Model. Unique predictions concern the remarkable collimation of jets and emissions from the jet/radiolobe structure. Given MBH and the accretion rate, the model makes 7 predictions roughly consistent with data: (1) the jet length; (2) the jet radius; (3) the steady-state cosmic ray energy spectrum; (4) the maximum energy in this spectrum; (5) the UHE cosmic ray intensity on Earth; (6) electron synchrotron wavelengths; and (7) the power in synchrotron radiation. These qualitative successes motivate new computer simulations, experiments and data analysis to provide a quantitative verification of the model.
Book Synopsis Propagation of Ultrahigh Energy Cosmic Rays in the Galaxy and Search for Their Sources by : Gwenael Giacinti
Download or read book Propagation of Ultrahigh Energy Cosmic Rays in the Galaxy and Search for Their Sources written by Gwenael Giacinti and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Energy Astrophysics by : Malcolm S. Longair
Download or read book High Energy Astrophysics written by Malcolm S. Longair and published by Cambridge University Press. This book was released on 2011-02-03 with total page 885 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing students with an in-depth account of the astrophysics of high energy phenomena in the Universe, the third edition of this well-established textbook is ideal for advanced undergraduate and beginning graduate courses in high energy astrophysics. Building on the concepts and techniques taught in standard undergraduate courses, this textbook provides the astronomical and astrophysical background for students to explore more advanced topics. Special emphasis is given to the underlying physical principles of high energy astrophysics, helping students understand the essential physics. The third edition has been completely rewritten, consolidating the previous editions into one volume. It covers the most recent discoveries in areas such as gamma-ray bursts, ultra-high energy cosmic rays and ultra-high energy gamma rays. The topics have been rearranged and streamlined to make them more applicable to a wide range of different astrophysical problems.
Book Synopsis Composition and Origin of Cosmic Rays by : M.M. Shapiro
Download or read book Composition and Origin of Cosmic Rays written by M.M. Shapiro and published by Springer. This book was released on 1983-07-31 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Topics in Cosmic-ray Astrophysics by : Michael DuVernois
Download or read book Topics in Cosmic-ray Astrophysics written by Michael DuVernois and published by Nova Biomedical Books. This book was released on 1999 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents recent findings on charged cosmic rays, primarily nuclei, from galactic and extra-galactic sources. Chapters on new and proposed instruments and techniques examine projects such as the SilEye and the PAMELA apparatus for the search of antimatter in cosmic rays. Papers on cosmic ray models look at nonlinear phenomena in diffusive shock acceleration, and propagation of cosmic rays in the galaxy. Material on cosmic ray sources and ultra-high energy cosmic rays examine source composition and its relation to the interstellar matter, and cosmic ray mass composition at highest energies. The editor is a researcher at Pennsylvania State University. Annotation copyrighted by Book News, Inc., Portland, OR
Book Synopsis Cosmic-ray Astronomy at the Highest Energies with Ten Years of Data of the Pierre Auger Observatory by : Lorenzo Caccianiga
Download or read book Cosmic-ray Astronomy at the Highest Energies with Ten Years of Data of the Pierre Auger Observatory written by Lorenzo Caccianiga and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Identifying the sources of the ultra-high energy cosmic rays (UHECRs, above 10^{18} eV), the most energetic particles known in the universe, would be an important leap forward for both the astrophysics and particle physics knowledge. However, developing a cosmic-ray astronomy is arduous because magnetic fields, that permeate our Galaxy and the extra-Galactic space, deflect cosmic rays that may lose the directional information on their sources. This problem can be reduced by studying the highest energy end of the cosmic ray spectrum. Indeed, magnetic field deflections are inversely proportional to the cosmic ray energy. Moreover, above 4x10^{19} eV, cosmic rays interact with cosmic photon backgrounds, losing energy. This means that the sources of the highest energy cosmic rays observed on Earth can be located only in the nearby universe (200 Mpc or less). The largest detector ever built for detecting cosmic rays at such high energies is the Pierre Auger Observatory, in Argentina. It combines a 3000 km^2 surface array of water Cherenkov detectors with fluorescence telescopes to measure extensive air showers initiated by the UHECRs. This thesis was developed inside the Auger Collaboration and was devoted to study the highest energy events observed by Auger, starting from the selection and reconstruction up to the analysis of their distribution in the sky. Moreover, since the composition at these energies is unknown, we developed a method to select proton-like events, since high Z cosmic rays are too much deflected by magnetic fields to be used for cosmic-ray astronomy.
Book Synopsis The ubiquitous mechanism accelerating cosmic rays at all the energies by : Antonio Codino
Download or read book The ubiquitous mechanism accelerating cosmic rays at all the energies written by Antonio Codino and published by Società Editrice Esculapio. This book was released on 2021-02-04 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanism accelerating Cosmic rays in the milky way galaxy and galaxy clusters is identified and described. The acceleration of Cosmic rays is a purely electrostatic process which operate up to the maximum energies of 1023 ev in galaxy clusters. Galactic Cosmic rays are accelerated in a pervasive electrostatic field active in the whole galaxy except in restricted regions shielded by Interstellar and stellar plasma as, for instance, the region occupied by the Solar system. It is proved that the Energy spectrum of the Cosmic radiation in the milky way galaxy, in the region where the Solar system resides, has a constant Spectral index comprised between 2.64-2.68 and the maximum energies of galactic protons are 3.0 × 1019 ev. The agreement of these results with the experimental data is discussed in detail and highlighted. The various physical processes that maintain the stability of the electrostatic structure in the milky way galaxy are the same that generate the galactic magnetic field. Accordingly, the intensity, orientation and direction of the galactic magnetic field are evaluated. The results of the calculation are compared with the observation data, optical and mostly radio astronomi data. The accord of the intensity, orientation and direction of the observed magnetic field with calculation is excellent.
