scholarly journals Modelling the Energy Spectra of Radio Relics

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 111
Author(s):  
Denis Wittor ◽  
Matthias Hoeft ◽  
Marcus Brüggen
Keyword(s):  
Tracer Particle ◽  
Galaxy Cluster ◽  
Cosmic Ray ◽  
Radio Spectrum ◽  
Adiabatic Compression ◽  
Energy Spectra ◽  
Similar Amount ◽  
Inverse Compton Scattering ◽  
Tracer Particles ◽  
Compression And Expansion

Radio relics are diffuse synchrotron sources that illuminate shock waves in the intracluster medium. In recent years, radio telescopes have provided detailed observations about relics. Consequently, cosmological simulations of radio relics need to provide a similar amount of detail. In this methodological work, we include information on adiabatic compression and expansion, which have been neglected in the past in the modelling of relics. In a cosmological simulation of a merging galaxy cluster, we follow the energy spectra of shock accelerated cosmic-ray electrons using Lagrangian tracer particles. On board of each tracer particle, we compute the temporal evolution of the energy spectrum under the influence of synchrotron radiation, inverse Compton scattering, and adiabatic compression and expansion. Exploratory tests show that the total radio power and, hence, the integrated radio spectrum are not sensitive to the adiabatic processes. This is attributed to small changes in the compression ratio over time.

EARLY RESULTS FROM THE HIGH-RESOLUTION FLY's EYE

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1019-1021
Author(s):  
JOHN BELZ
Keyword(s):  
High Resolution ◽  
Cosmic Ray ◽  
Energy Spectra ◽  
Fluorescence Technique ◽  
Early Results ◽  
One Year ◽  
High Resolution Fly's Eye

The High-Resolution Fly's Eye cosmic ray observatory has been operating in monocular (stereo) mode for about three years (one year), during which time we have observed extensive airshowers with an integrated aperture of ~ 1500 km2-sr-yr (~ 400 km-sr-yr) at 5×1019 eV. We describe the HiRes experiment and the nitrogen fluorescence technique, and present data taken in both monocular and stereo modes including preliminary energy spectra.

TRACER TIME DISTRIBUTION OF PARTICLES IN POROUS MEDIA

Fractals ◽  
1993 ◽  
Vol 01 (04) ◽  
pp. 1075-1079
Author(s):  
MARIELA ARAUJO
Keyword(s):  
Porous Medium ◽  
Transit Time ◽  
Power Law ◽  
Time Distribution ◽  
Tracer Particle ◽  
Power Law Distribution ◽  
Low Velocity ◽  
Constant Flow Rate ◽  
Variable Permeability ◽  
Tracer Particles

We study the transit time distributions of tracer particles in a porous medium through which a constant flow rate is established. Our model assumes that non-Gaussian dispersion is due to the presence of low velocity zones or channels in parallel with a faster flow path. Each channel is represented as a trap and simulates the existence of variable permeability blocks inside the porous medium. The time the tracer particle spends inside each channel is related to the heterogeneity of the sample, and is assumed here to have a power-law distribution. We compare the transit time distribution of these particles for the case in which the traps are Poisson distributed with the one in which the trap distribution is a power-law function.

Energy spectra of different groups of cosmic ray nuclei from Cerenkov counter measurements in satellite vehicles

1963 ◽  
Vol 11 (2) ◽  
pp. 193-208
Author(s):  
L.V. Kurnosova ◽  
V.I. Logachev ◽  
L.A. Razorenov ◽  
M.I. Fradkin
Keyword(s):  
Cosmic Ray ◽  
Energy Spectra ◽  
Cerenkov Counter

scholarly journals ENERGY SPECTRA OF PRIMARY AND SECONDARY COSMIC-RAY NUCLEI MEASURED WITH TRACER

2011 ◽  
Vol 742 (1) ◽  
pp. 14 ◽  
Author(s):  
A. Obermeier ◽  
M. Ave ◽  
P. Boyle ◽  
Ch. Höppner ◽  
J. Hörandel ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Energy Spectra

scholarly journals Fermi-LAT and WMAP observations of the supernova remnant Puppis A

2013 ◽  
Vol 9 (S296) ◽  
pp. 295-299
Author(s):  
Marie-Hélène Grondin ◽  
John W. Hewitt ◽  
Marianne Lemoine-Goumard ◽  
Thierry Reposeur ◽  
Keyword(s):  
Supernova Remnants ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
High Energy ◽  
Radio Spectrum ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Large Area ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Γ Ray

AbstractThe supernova remnant (SNR) Puppis A (aka G260.4-3.4) is a middle-aged supernova remnant, which displays increasing X-ray surface brightness from West to East corresponding to an increasing density of the ambient interstellar medium at the Eastern and Northern shell. The dense IR photon field and the high ambient density around the remnant make it an ideal case to study in γ-rays. Gamma-ray studies based on three years of observations with the Large Area Telescope (LAT) aboard Fermi have revealed the high energy gamma-ray emission from SNR Puppis A. The γ-ray emission from the remnant is spatially extended, and nicely matches the radio and X-ray morphologies. Its γ-ray spectrum is well described by a simple power law with an index of ~2.1, and it is among the faintest supernova remnants yet detected at GeV energies. To constrain the relativistic electron population, seven years of Wilkinson Microwave Anisotropy Probe (WMAP) data were also analyzed, and enabled to extend the radio spectrum up to 93 GHz. The results obtained in the radio and γ-ray domains are described in detail, as well as the possible origins of the high energy γ-ray emission (Bremsstrahlung, Inverse Compton scattering by electrons or decay of neutral pions produced by proton interactions).

scholarly journals Galactic cosmic-ray energy spectra and expected solar events at the time of future space missions

2011 ◽  
Vol 28 (9) ◽  
pp. 094005 ◽  
Author(s):  
C Grimani ◽  
H M Araújo ◽  
M Fabi ◽  
A Lobo ◽  
I Mateos ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Space Missions ◽  
Energy Spectra ◽  
Future Space ◽  
Solar Events ◽  
Galactic Cosmic Ray

Tracer trajectories and displacement due to a micro-swimmer near a surface

2015 ◽  
Vol 773 ◽  
pp. 498-519 ◽  
Author(s):  
A. J. T. M. Mathijssen ◽  
D. O. Pushkin ◽  
J. M. Yeomans
Keyword(s):  
Particle Transport ◽  
Numerical Study ◽  
Tracer Particle ◽  
Persistence Length ◽  
Theoretical Work ◽  
Solid Boundary ◽  
Tracer Transport ◽  
Tracer Particles ◽  
Recent Theoretical Work ◽  
Run And Tumble

We study tracer particle transport due to flows created by a self-propelled micro-swimmer, such as a swimming bacterium, alga or a microscopic artificial swimmer. Recent theoretical work has shown that as a swimmer moves in the fluid bulk along an infinite straight path, tracer particles far from its path perform closed loops, whereas those close to the swimmer are entrained by its motion. However, in biologically and technologically important cases tracer transport is significantly altered for swimmers that move in a run-and-tumble fashion with a finite persistence length, and/or in the presence of a free surface or a solid boundary. Here we present a systematic analytical and numerical study exploring the resultant regimes and their crossovers. Our focus is on describing qualitative features of the tracer particle transport and developing quantitative tools for its analysis. Our work is a step towards understanding the ecological effects of flows created by swimming organisms, such as enhanced fluid mixing and biofilm formation.

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