scholarly journals High-energy particles from SN-explosions near the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 454-455
Author(s):  
Ernst A. Dorfi ◽  
Daniel Steiner
Keyword(s):  
Shock Waves ◽  
Galactic Center ◽  
Galactic Plane ◽  
Strong Shock ◽  
High Energy ◽  
Pressure Gradients ◽  
Dependent Mass ◽  
High Energy Particles ◽  
Relativistic Particles ◽  
Compact Cluster

AbstractSeveral supernovae exploding in a compact cluster of massive stars generate a galactic outflow with embedded shock waves. Based on numerical simulations for an expanding superbubble above the Galactic center we find that these individual waves generated by the repeated SN-explosions, interact with each other and finally coalesce into a single strong shock at a distance of 5 kpc above the Galactic plane at about 5 ċ 106 years after outbreak. The resulting shock with a Mach number M ≃ 10 propagates up to 100 kpc in less than 108 years. The time-dependent mass an energy loss out of the superbubble affects the further evolution of the outflow. In such long lasting shock waves energetic particles can be accelerated above the knee of 1015 eV already near the galactic plane by a first-order Fermi-mechanism. The additional pressure gradients from such cosmic rays lead to further accelerations of the galactic outflow since these ultra-relativistic particles suffer less from adiabatic losses than the thermal gas.

Measurement of ionization loss of 50 GeV protons in silicon with smoothly tunable up to 1 cm thickness using a single flat detector

2022 ◽  
Vol 17 (01) ◽  
pp. P01015
Author(s):  
R.M. Nazhmudinov ◽  
A.V. Shchagin ◽  
A.S. Kubankin ◽  
A.G. Afonin ◽  
G.I. Britvich ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Silicon Detector ◽  
Incident Beam ◽  
High Energy ◽  
Silicon Detectors ◽  
Arbitrary Angle ◽  
Ionization Loss ◽  
Flat Detector ◽  
High Energy Particles ◽  
Relativistic Particles

Abstract Research of the ionization loss of 50 GeV protons, the path of which in the depleted layer of the silicon detector was smoothly regulated in the range from 0.3 to 10 mm, is presented. In the experiment, we used a flat silicon detector with a fixed thickness of the depleted layer of 300 μm. The smooth regulation of the path was realized due to the variation of the angle between the surface of the detector and the incident proton beam. The comparison of experimental data and theoretical calculations of the ionization loss demonstrates agreement in all range of thicknesses. Results of the research can be used in order to control the angle between the surface of the detector and the incident beam of relativistic particles. Besides, the results can be used in the analysis of data from astrophysical silicon detectors of charged particles if high-energy particles crossed flat detectors at arbitrary angle.

scholarly journals The Nature of the Galactic Center Arc

1996 ◽  
Vol 169 ◽  
pp. 263-269 ◽  
Author(s):  
E. Serabyn
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Galactic Center ◽  
Magnetic Energy ◽  
Linear Structure ◽  
High Energy ◽  
Molecular Gas ◽  
Synchrotron Emission ◽  
Interferometric Imaging ◽  
Relativistic Particles

Ever since the Galactic Center Arc was resolved into its component filaments a decade ago, it has been clear that its linear structure arises from the influence of a strong magnetic field. However, the origin and nature of the contributory phenomena have remained elusive. Since what is seen is synchrotron emission from relativistic particles, of prime interest is a knowledge of the acceleration mechanism involved. Interferometric imaging of the molecular gas in the vicinity of the Arc has now provided a tantalizing clue to the Arc's origin: molecular clumps coinciding with the endpoints of a number of the Arc's filaments point to these clumps as the source of the relativistic particles. This suggests that as dense molecular clumps course through the ambient magnetic field at the Galactic Center, magnetic energy is liberated in their leading layers via field reconnection, precipitating rapid acceleration of free charges to high energy.

scholarly journals 7.13. The Sgr A East HII complex and associated features

1998 ◽  
Vol 184 ◽  
pp. 317-318 ◽  
Author(s):  
Keven I. Uchida ◽  
Mark R. Morris ◽  
Gene Serabyn ◽  
David Fong ◽  
Thomas Meseroll
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Galactic Center ◽  
Galactic Plane ◽  
Alternative Hypothesis ◽  
Rapid Expansion ◽  
H Ii Regions ◽  
Expansion Time ◽  
Sgr A ◽  
Relativistic Particles

The Sgr A East H ii complex consists of 4 compact H ii regions situated just east of and following, in an arc pattern, the edge of the Sgr A East nonthermal shell. Located between the arc of H ii regions and the nonthermal shell is a dense molecular ridge – presumably compressed – known as the “50 km/s cloud”. The hypothesis that these H ii regions delineate massive star formation provoked by the rapid expansion of Sgr A East into the molecular cloud is problematical because of the mismatch of the shell expansion and star formation time scales. We therefore examine the alternative hypothesis that Sgr A East is a quasi-static or slowly expanding structure fed from within by the release of relativistic particles from sources at or near the nucleus. The elongation of SgrA East along the Galactic plane is ascribed to the shear inherent in the velocity field this close to the Galactic center (GC). In this proceeding we discuss our ongoing efforts to model the effects of shear in detail, using the elongation of Sgr A East to constrain its expansion time scale.

scholarly journals What are the Radio Filaments Near the Galactic Center?

1996 ◽  
Vol 169 ◽  
pp. 247-261 ◽  
Author(s):  
Mark Morris
Keyword(s):  
Magnetic Field ◽  
Galactic Center ◽  
Galactic Plane ◽  
Local Source ◽  
Flux Tubes ◽  
Flux Lines ◽  
Magnetic Flux Tubes ◽  
The Magnetic Field ◽  
Relativistic Particles ◽  
Projected Distance

A population of nonthermally-emitting radio filaments tens of parsecs in length has been observed within a projected distance of ∼130 pc of the Galactic center. More or less perpendicular to the Galactic plane, they appear to define the flux lines of a milligauss magnetic field. The characteristics of the known filaments are summarized. Three fundamental questions raised by these structures are discussed: 1) Do they represent magnetic flux tubes embedded within an ubiquitous, dipole magnetic field permeating the inner Galaxy, but which have been illuminated by some local source of relativistic particles, or are they instead isolated, self-sustaining current paths with an approximately force-free magnetic configuration in pressure equilibrium with the interstellar medium? 2) What is the source of either the magnetic field or the current? and 3) What is the source of the relativistic particles which provide the illuminating synchrotron radiation? We are nearer an answer to the the last of these questions than to the others, although several interesting models have been proposed.

scholarly journals The H.E.S.S. Galactic plane survey

2018 ◽  
Vol 612 ◽  
pp. A1 ◽  
Author(s):  
◽  
H. Abdalla ◽  
A. Abramowski ◽  
F. Aharonian ◽  
F. Ait Benkhali ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Large Scale ◽  
Gamma Ray ◽  
Galactic Center ◽  
Galactic Plane ◽  
High Energy ◽  
High Angular Resolution ◽  
Data Set ◽  
Cherenkov Telescopes ◽  
Spatial Coverage

We present the results of the most comprehensive survey of the Galactic plane in very high-energy (VHE) γ-rays, including a public release of Galactic sky maps, a catalog of VHE sources, and the discovery of 16 new sources of VHE γ-rays. The High Energy Spectroscopic System (H.E.S.S.) Galactic plane survey (HGPS) was a decade-long observation program carried out by the H.E.S.S. I array of Cherenkov telescopes in Namibia from 2004 to 2013. The observations amount to nearly 2700 h of quality-selected data, covering the Galactic plane at longitudes from ℓ = 250° to 65° and latitudes |b|≤ 3°. In addition to the unprecedented spatial coverage, the HGPS also features a relatively high angular resolution (0.08° ≈ 5 arcmin mean point spread function 68% containment radius), sensitivity (≲1.5% Crab flux for point-like sources), and energy range (0.2–100 TeV). We constructed a catalog of VHE γ-ray sources from the HGPS data set with a systematic procedure for both source detection and characterization of morphology and spectrum. We present this likelihood-based method in detail, including the introduction of a model component to account for unresolved, large-scale emission along the Galactic plane. In total, the resulting HGPS catalog contains 78 VHE sources, of which 14 are not reanalyzed here, for example, due to their complex morphology, namely shell-like sources and the Galactic center region. Where possible, we provide a firm identification of the VHE source or plausible associations with sources in other astronomical catalogs. We also studied the characteristics of the VHE sources with source parameter distributions. 16 new sources were previously unknown or unpublished, and we individually discuss their identifications or possible associations. We firmly identified 31 sources as pulsar wind nebulae (PWNe), supernova remnants (SNRs), composite SNRs, or gamma-ray binaries. Among the 47 sources not yet identified, most of them (36) have possible associations with cataloged objects, notably PWNe and energetic pulsars that could power VHE PWNe.

The Calculation of Elastic Modulus Behind Strong Shock Waves

2009 ◽  
Vol 4 (4) ◽  
pp. 79-90
Author(s):  
Evgeny Kraus
Keyword(s):  
Shock Waves ◽  
Mechanical Characteristics ◽  
Strong Shock ◽  
High Energy ◽  
High Energy Density ◽  
Uniform System ◽  
Comprehensive Comparison ◽  
State 1 ◽  
Strong Shock Waves ◽  
Good Agreement

In the paper the approach for calculation of mechanical characteristics of materials behind strong shock waves is realized in the frame of uniform system of the few-parametric equation of state [1]. For the considered materials a comprehensive comparison of theoretical computational results with available at high energy density experimental data is carried out and good agreement of the results is obtained

scholarly journals Uv Galaxies

1983 ◽  
Vol 6 ◽  
pp. 459-466 ◽  
Author(s):  
E. Ye Khachikian
Keyword(s):  
Absolute Magnitude ◽  
High Energy ◽  
List Type ◽  
Type Number ◽  
Nuclear Region ◽  
Continuous Emission ◽  
Radio Halo ◽  
High Energy Particles ◽  
Relativistic Particles

The systematical statement of the concept of the activity of the nuclei of galaxies was first made public by Ambartsumian about 25 years ago (Ambartsumian 1958, 1962, 1965). Since 1965 he has been advancing and developing the idea of the basic role of the nuclei of galaxies in their life and evolution.According to Ambartsumian the “activity” of the nuclei of galaxies manifests itself mainly in the following forms: 1.Outflow of ordinary gas matter (in form of jets or clouds) from the nuclear region at the velocity of up to hundreds of kilometres per second.2.Continuous emission of the flux of relativistic particles or other agents, producing high energy particles, as a result of which a radio halo may form around the nucleus.3.Eruptive ejections of gas matter (M82 type).4.Eruptive ejections of concentrations of relativistic plasma (NGC 4486, 5128, etc.)I should like to emphasize on the form of activity which says: 5.Ejection of compact blue condensations with an absolute magnitude of the order of luminosity of dward galaxies (NGC 3561, IC 1182). Here the division of the nucleus into two or more comparable componentsis also presumed; initiating the formation of multiple galaxies.

Chapter 2 Galactic Gamma-ray Sources

2021 ◽  
Author(s):  
Yang Chen ◽  
Xiao Zhang
Keyword(s):  
Supernova Remnants ◽  
Gamma Ray ◽  
Galactic Center ◽  
Galactic Plane ◽  
Theoretical Models ◽  
High Energy ◽  
Maximum Energy ◽  
Radiation Mechanisms ◽  
Galactic Sources ◽  
Very High

Abstract In the gamma-ray sky, the highest fluxes come from Galactic sources: supernova remnants (SNRs), pulsars and pulsar wind nebulae, star forming regions, binaries and micro-quasars, giant molecular clouds, Galactic center, and the large extended area around the Galactic plane. The radiation mechanisms of -ray emission and the physics of the emitting particles, such as the origin, acceleration, and propagation, are of very high astrophysical significance. A variety of theoretical models have been suggested for the relevant physics and emission with energies E_1014 eV are expected to be crucial in testing them. In particular, this energy band is a direct window to test at which maximum energy a particle can be accelerated in the Galactic sources and whether the most probable source candidates such as Galactic center and SNRs are “PeVatrons”. Designed aiming at the very high energy (VHE, >100 GeV) observation, LHAASO will be a very powerful instrument in these astrophysical studies. Over the past decade, great advances have been made in the VHE -ray astronomy. More than 170 VHE -ray sources have been observed, and among them, 42 Galactic sources fall in the LHAASO field-of-view. With a sensitivity of 10 milli-Crab, LHAASO can not only provide accurate spectrum for the known -ray sources, but also search new TeV -ray sources. In the following sub-sections, the observation of all the Galactic sources with LHAASO will be discussed in details.

scholarly journals Latest results on high-energy cosmic neutrino searches with the ANTARES neutrino telescope

2019 ◽  
Vol 210 ◽  
pp. 03004
Author(s):  
Agustín Sánchez Losa
Keyword(s):  
Galactic Center ◽  
Galactic Plane ◽  
Cosmic Ray ◽  
High Energy ◽  
Neutrino Telescope ◽  
Southern Coast ◽  
Transient Phenomena ◽  
Neutrino Production ◽  
Cosmic Neutrino ◽  
Extended Sources

The ANTARES detector is currently the largest undersea neutrino telescope. Located in the Mediterranean Sea at a depth of 2.5 km, 40 km off the Southern coast of France, it has been looking for cosmic neutrinos for more than 10 years. High-energy cosmic neutrino production is strongly linked with cosmic ray production. The latest results from IceCube Collaboration represent a step forward towards the confirmation of a highenergy cosmic ray source. The ANTARES location in the Northern Hemisphere is optimal for the observation of most of the Galactic Plane, including the Galactic Center. It has constrained the IceCube neutrino excess reports as well as, more recently, the flux from the source identified in the Blazar TXS 0506+056. The latest results of ANTARES on such analyses, including point-like and extended sources, diffuse fluxes, transient phenomena and multi-messenger studies, are presented.

scholarly journals Shock waves raised by explosions in space as sources of ultra-high-energy cosmic rays

10.12737/7350 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 109-114
Author(s):  
Геннадий Кичигин ◽  
Gennadiy Kichigin
Keyword(s):  
Cosmic Rays ◽  
Shock Waves ◽  
Charged Particles ◽  
Strong Shock ◽  
High Energy ◽  
Ultra High Energy ◽  
Langmuir Waves ◽  
High Energy Cosmic Rays ◽  
Spherical Waves ◽  
Strong Shock Waves

The paper discusses the possibility of particle acceleration up to ultrahigh energies in the relativistic waves generated by various explosive processes in the interstellar medium. We propose to use the surfatron mechanism of acceleration (surfing) of charged particles trapped in the front of relativistic waves as a generator of high-energy cosmic rays (CRs). Conditions under which surfing in these waves can be made are studied thoroughly. Ultra-high-energy CRs are shown to be obtained due to the surfing in the relativistic plane and spherical waves. Surfing is supposed to take place in nonlinear Langmuir waves excited by powerful electromagnetic radiation or relativistic beams of charged particles, as well as in strong shock waves generated by relativistic jets or spherical formations that expand fast (fireballs).

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