scholarly journals Studying Cosmic Ray Sources Using Intergalactic Electromagnetic Cascades

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 287
Author(s):  
Anna Uryson
Keyword(s):  
Black Holes ◽  
Particle Acceleration ◽  
Cosmic Rays ◽  
Gamma Ray ◽  
Relative Number ◽  
Cosmic Ray ◽  
Supermassive Black Holes ◽  
Joint Analysis ◽  
Particle Injection ◽  
Superstrong Magnetic Field

In this paper, intergalactic electromagnetic cascades are used as a probe of cosmic ray sources. This is achieved as follows. In extragalactic space, cosmic rays initiate electromagnetic cascades, in which gamma-ray and neutrino emission arises. We used the joint analysis of cosmic ray data, along with extragalactic gamma-ray and neutrino emissions, to study particle acceleration in the vicinity of supermassive black holes. Particle injection spectra depend on processes of particle acceleration, and here we discuss models with various injection spectra. The computations of the propagation of cosmic rays in space were performed using the publicly available TransportCR code. It was found that a new subclass of sources might exist that does not contribute to the particle flux on Earth, instead to gamma-ray and neutrino emissions arising in electromagnetic cascades. In addition, the upper limit of the relative number of ‘exotic’ supermassive black holes surrounded by a superstrong magnetic field is derived.

scholarly journals Messengers of the Universe-Cosmic Rays Exploring Supermassive Black Holes

Galaxies ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 2
Author(s):  
Anna Uryson
Keyword(s):  
Black Holes ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Supermassive Black Holes ◽  
High Energies ◽  
Recent Developments ◽  
The Universe

Cosmic rays were discovered over one hundred years ago but there are still unsolved problems. One of the hot problems is the origin of cosmic rays of the highest energies. Sources are still unclear and it is neither clear how particles gain ultra-high energies. Possible sources of cosmic rays at the highest energies are supermassive black holes. From this perspective we discuss in a popular form some recent developments in cosmic ray studies along with author’s recent results. The paper also offers materials for further reading.

Influence of supernovae, gamma-ray bursts, solar flares, and cosmic rays on the terrestrial environment

2008 ◽  
Author(s):  
Arnon Dar
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Gamma Ray Bursts ◽  
The Sun ◽  
Terrestrial Environment ◽  
The Earth ◽  
The Galaxy ◽  
Threat To Life

Changes in the solar neighbourhood due to the motion of the sun in the Galaxy, solar evolution, and Galactic stellar evolution influence the terrestrial environment and expose life on the Earth to cosmic hazards. Such cosmic hazards include impact of near-Earth objects (NEOs), global climatic changes due to variations in solar activity and exposure of the Earth to very large fluxes of radiations and cosmic rays from Galactic supernova (SN) explosions and gamma-ray bursts (GRBs). Such cosmic hazards are of low probability, but their influence on the terrestrial environment and their catastrophic consequences, as evident from geological records, justify their detailed study, and the development of rational strategies, which may minimize their threat to life and to the survival of the human race on this planet. In this chapter I shall concentrate on threats to life from increased levels of radiation and cosmic ray (CR) flux that reach the atmosphere as a result of (1) changes in solar luminosity, (2) changes in the solar environment owing to the motion of the sun around the Galactic centre and in particular, owing to its passage through the spiral arms of the Galaxy, (3) the oscillatory displacement of the solar system perpendicular to the Galactic plane, (4) solar activity, (5) Galactic SN explosions, (6) GRBs, and (7) cosmic ray bursts (CRBs). The credibility of various cosmic threats will be tested by examining whether such events could have caused some of the major mass extinctions that took place on planet Earth and were documented relatively well in the geological records of the past 500 million years (Myr). A credible claim of a global threat to life from a change in global irradiation must first demonstrate that the anticipated change is larger than the periodical changes in irradiation caused by the motions of the Earth, to which terrestrial life has adjusted itself. Most of the energy of the sun is radiated in the visible range. The atmosphere is highly transparent to this visible light but is very opaque to almost all other bands of the electromagnetic spectrum except radio waves, whose production by the sun is rather small.

scholarly journals Cosmic Rays and the Dynamic Balance in the Large Magellanic Cloud

1990 ◽  
Vol 123 ◽  
pp. 537-541
Author(s):  
Carl E. Fichtel ◽  
Mehmet E. Ozel ◽  
Robert G. Stone
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
Dynamic Balance ◽  
Cosmic Ray ◽  
Large Magellanic Cloud ◽  
High Energy ◽  
Magellanic Cloud ◽  
Density Level ◽  
Energy Gamma ◽  
Galactic Dynamic

AbstractPresent and future measurement of the Large Magellanic Cloud (LMC) particularly in the radio and high energy gamma ray range offer the possibility of understanding the density and distribution of the cosmic rays in a galaxy other than our own and the role that they play in galactic dynamic balance. After a study of the consistency of the measurements and interpretation of the synchrotron radiation from our own galaxy, the cosmic ray distribution for the LMC is calculated under the assumption that the cosmic ray nucleon to electron ratio is the same and the relation to the magnetic fields are the same, although the implications of alternatives are discussed. It is seen that the cosmic ray density level appears to be similar to that in our own galaxy, but varying in position in a manner generally consistent with the concept of correlation with the matter on a broad scale.

scholarly journals Linking supernovae and supernova remnants. Time-dependent injection in SN1987A and gamma-ray spectrum of IC443

2017 ◽  
Vol 12 (S331) ◽  
pp. 268-273
Author(s):  
O. Petruk ◽  
S. Orlando ◽  
M. Miceli
Keyword(s):  
Gamma Rays ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Supernova Explosion ◽  
Cosmic Ray ◽  
Proton Spectrum ◽  
Stationary Equation ◽  
Particle Injection ◽  
Particle Momentum ◽  
Number Of Particles

AbstractAcceleration times of particles responsible for the gamma-rays in supernova remnants (SNRs) are comparable with SNR age. If the number of particles starting acceleration was varying during early times after the supernova explosion then this variation should be reflected in the shape of the gamma-ray spectrum. In order to analyse this effect, we consider the time variation of the radio spectral index in SN1987A and solution of the non-stationary equation for particle acceleration. We reconstruct evolution of the particle injection in SN1987A, apply it to derive the particle momentum distribution in IC443 and model its gamma-ray spectrum. We show that: i) observed break in the proton spectrum around 50 GeV in IC443 is a consequence of the variation of the cosmic ray injection; ii) shape of the hadronic gamma-ray spectrum in SNRs critically depends on the temporal variation of the cosmic ray injection in the immediate post explosion phases.

scholarly journals CAN DIRECT COLLAPSE BLACK HOLES LAUNCH GAMMA-RAY BURSTS AND GROW TO SUPERMASSIVE BLACK HOLES?

2015 ◽  
Vol 810 (1) ◽  
pp. 64 ◽  
Author(s):  
Tatsuya Matsumoto ◽  
Daisuke Nakauchi ◽  
Kunihito Ioka ◽  
Alexander Heger ◽  
Takashi Nakamura
Keyword(s):  
Black Holes ◽  
Gamma Ray ◽  
Supermassive Black Holes ◽  
Gamma Ray Bursts

A SHORT, CRITICAL REVIEW ON GAMMA-RAY EMISSION FROM GALAXY CLUSTERS

2009 ◽  
Vol 18 (10) ◽  
pp. 1541-1544
Author(s):  
SERGIO COLAFRANCESCO
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Cosmic Rays ◽  
Galaxy Clusters ◽  
Critical Review ◽  
Particle Physics ◽  
Gamma Ray ◽  
Gamma Ray Emission ◽  
The Impact

We discuss the relevance of gamma-ray observations of galaxy clusters, to unveil several issues that are relevant for Cosmology and Astro-Particle Physics of cosmic structures: the nature of Dark Matter, the origin of cosmic rays and the impact of black holes.

scholarly journals Particle acceleration in winds of star clusters

2021 ◽  
Author(s):  
G Morlino ◽  
P Blasi ◽  
E Peretti ◽  
P Cristofari
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Supernova Remnants ◽  
Star Clusters ◽  
Cosmic Ray ◽  
Maximum Energy ◽  
Termination Shock ◽  
Shock Acceleration ◽  
Acceleration Process ◽  
Diffusive Shock Acceleration

Abstract The origin of cosmic rays in our Galaxy remains a subject of active debate. While supernova remnant shocks are often invoked as the sites of acceleration, it is now widely accepted that the difficulties of such sources in reaching PeV energies are daunting and it seems likely that only a subclass of rare remnants can satisfy the necessary conditions. Moreover the spectra of cosmic rays escaping the remnants have a complex shape that is not obviously the same as the spectra observed at the Earth. Here we investigate the process of particle acceleration at the termination shock that develops in the bubble excavated by star clusters’ winds in the interstellar medium. While the main limitation to the maximum energy in supernova remnants comes from the need for effective wave excitation upstream so as to confine particles in the near-shock region and speed up the acceleration process, at the termination shock of star clusters the confinement of particles upstream in guaranteed by the geometry of the problem. We develop a theory of diffusive shock acceleration at such shock and we find that the maximum energy may reach the PeV region for powerful clusters in the high end of the luminosity tail for these sources. A crucial role in this problem is played by the dissipation of energy in the wind to magnetic perturbations. Under reasonable conditions the spectrum of the accelerated particles has a power law shape with a slope 4÷4.3, in agreement with what is required based upon standard models of cosmic ray transport in the Galaxy.

scholarly journals Gamma-ray emitting supernova remnants as the origin of Galactic cosmic rays

2015 ◽  
Vol 2 ◽  
pp. 57-62 ◽  
Author(s):  
M. Kroll ◽  
J. Becker Tjus ◽  
B. Eichmann ◽  
N. Nierstenhöfer
Keyword(s):  
Cosmic Rays ◽  
Energy Budget ◽  
Thermal Energy ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Below The Knee ◽  
Individual Contributions ◽  
First Time

Abstract. It is generally believed that the cosmic ray spectrum below the knee is of Galactic origin, although the exact sources making up the entire cosmic ray energy budget are still unknown. Including effects of magnetic amplification, Supernova Remnants (SNR) could be capable of accelerating cosmic rays up to a few PeV and they represent the only source class with a sufficient non-thermal energy budget to explain the cosmic ray spectrum up to the knee. Now, gamma-ray measurements of SNRs for the first time allow to derive the cosmic ray spectrum at the source, giving us a first idea of the concrete, possible individual contributions to the total cosmic ray spectrum. In this contribution, we use these features as input parameters for propagating cosmic rays from its origin to Earth using GALPROP in order to investigate if these supernova remnants reproduce the cosmic ray spectrum and if supernova remnants in general can be responsible for the observed energy budget.

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