scholarly journals Radiative cooling rates, ion fractions, molecule abundances, and line emissivities including self-shielding and both local and metagalactic radiation fields

2020 ◽  
Vol 497 (4) ◽  
pp. 4857-4883 ◽  
Author(s):  
Sylvia Ploeckinger ◽  
Joop Schaye
Keyword(s):  
Cosmic Rays ◽  
Radiation Field ◽  
Spectral Synthesis ◽  
Cosmic Ray ◽  
Cooling Rates ◽  
Radiation Fields ◽  
Hydrodynamical Simulations ◽  
Lower Temperature ◽  
X Ray Background ◽  
Ionization Balance

ABSTRACT We use the spectral synthesis code cloudy to tabulate the properties of gas for an extensive range in redshift (z = 0–9), temperature (log T[K] = 1–9.5), metallicity (log Z/Z⊙ = −4 – +0.5, Z = 0), and density ($\log n_{\mathrm{H}}[\, \mathrm{cm}^{-3}] = -8$ − +6). This therefore includes gas with properties characteristic of the interstellar, circumgalactic, and intergalactic media. The gas is exposed to a redshift-dependent UV/X-ray background, while for the self-shielded lower-temperature gas (i.e. ISM gas), an interstellar radiation field and cosmic rays are added. The radiation field is attenuated by a density- and temperature-dependent column of gas and dust. Motivated by the observed star formation law, this gas column density also determines the intensity of the interstellar radiation field and the cosmic ray density. The ionization balance, molecule fractions, cooling rates, line emissivities, and equilibrium temperatures are calculated self-consistently. We include dust, cosmic rays, and the interstellar radiation field step-by-step to study their relative impact. These publicly available tables are ideal for hydrodynamical simulations. They can be used stand alone or coupled to a non-equilibrium network for a subset of elements. The release includes a C routine to read in and interpolate the tables, as well as an easy-to-use python graphical user interface to explore the tables.

scholarly journals Diffuse cosmic X-rays from non-thermal intergalactic bremsstrahlung

1970 ◽  
Vol 37 ◽  
pp. 392-401
Author(s):  
Joseph Silk
Keyword(s):  
Cosmic Rays ◽  
Intergalactic Medium ◽  
Energy Requirement ◽  
Cosmic Ray ◽  
X Rays ◽  
Degree Of Ionization ◽  
X Ray ◽  
Normal Galaxies ◽  
X Ray Background ◽  
High Degree

The diffuse X-ray background between 1 keV and 1 MeV is interpreted as non-thermal bremsstrahlung in the intergalactic medium. The observed break in the X-ray spectrum at ∼40 keV yields the heat input to the intergalactic medium, the break being produced by ionization losses of sub-cosmic rays. Proton bremsstrahlung is found not to yield as satisfactory an agreement with observations as electron bremsstrahlung: excessive heating tends to occur. Two alternative models of cosmic ray injection are discussed, one involving continuous injection by evolving sources out to a redshift of about 3, and the other model involving injection by a burst of cosmic rays at a redshift of order 10. The energy density of intergalactic electrons required to produce the observed X-rays is ∼ 10−4 eV/cm3. Assuming a high density (∼ 10−5 cm−3) intergalactic medium, the energy requirement for cosmic ray injection by normal galaxies is ∼ 1058–59ergs/galaxy in sub-cosmic rays. The temperature evolution of the intergalactic medium is discussed, and we find that a similar energy input is also required to explain the observed high degree of ionization (if 3C9 is at a cosmological distance).

New fermionic dark matters, extended Standard Model and cosmic rays

2017 ◽  
Vol 32 (26) ◽  
pp. 1730023 ◽  
Author(s):  
Jae-Kwang Hwang
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Elementary Particles ◽  
X Ray ◽  
High Energy Cosmic Rays ◽  
Dark Matters ◽  
X Ray Background ◽  
New Particles

Three generations of leptons and quarks correspond to the lepton charges (LCs) in this work. Then, the leptons have the electric charges (ECs) and LCs. The quarks have the ECs, LCs and color charges (CCs). Three heavy leptons and three heavy quarks are introduced to make the missing third flavor of EC. Then the three new particles which have the ECs are proposed as the bastons (dark matters) with the rest masses of 26.121 eV/c2, 42.7 GeV/c2 and 1.9 × 10[Formula: see text] eV/c2. These new particles are applied to explain the origins of the astrophysical observations like the ultra-high energy cosmic rays and supernova 1987A anti-neutrino data. It is concluded that the 3.5 keV X-ray peak observed from the cosmic X-ray background spectra is originated not from the pair annihilations of the dark matters but from the X-ray emission of the Q1 baryon atoms which are similar in the atomic structure to the hydrogen atom. The presence of the 3.5 keV cosmic X-ray supports the presence of the Q1 quark with the EC of −4/3. New particles can be indirectly seen from the astrophysical observations like the cosmic ray and cosmic gamma ray. In this work, the systematic quantized charges of EC, LC and CC for the elementary particles are used to consistently explain the decay and reaction schemes of the elementary particles. Also, the strong, weak and dark matter forces are consistently explained.

scholarly journals Gamma Rays as Probes of Cosmic-Ray Propagation and Interactions in Galaxies

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 141
Author(s):  
Luigi Tibaldo ◽  
Daniele Gaggero ◽  
Pierrick Martin
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Local Interstellar Medium ◽  
New Developments ◽  
Star Forming ◽  
Radiation Fields ◽  
The Status ◽  
The Subject

Continuum gamma-ray emission produced by interactions of cosmic rays with interstellar matter and radiation fields is a probe of non-thermal particle populations in galaxies. After decades of continuous improvements in experimental techniques and an ever-increasing sky and energy coverage, gamma-ray observations reveal in unprecedented detail the properties of galactic cosmic rays. A variety of scales and environments are now accessible to us, from the local interstellar medium near the Sun and the vicinity of cosmic-ray accelerators, out to the Milky Way at large and beyond, with a growing number of gamma-ray emitting star-forming galaxies. Gamma-ray observations have been pushing forward our understanding of the life cycle of cosmic rays in galaxies and, combined with advances in related domains, they have been challenging standard assumptions in the field and have spurred new developments in modelling approaches and data analysis methods. We provide a review of the status of the subject and discuss perspectives on future progress.

scholarly journals The Origin and Dynamical Effects of the Magnetic Fields and Cosmic Rays in the Disk of the Galaxy

1970 ◽  
Vol 39 ◽  
pp. 168-183
Author(s):  
E. N. Parker
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Dynamical Behavior ◽  
Cosmic Ray ◽  
Interested Reader ◽  
Written Text ◽  
The Galaxy ◽  
Basic Ideas ◽  
The Magnetic Field

The topic of this presentation is the origin and dynamical behavior of the magnetic field and cosmic-ray gas in the disk of the Galaxy. In the space available I can do no more than mention the ideas that have been developed, with but little explanation and discussion. To make up for this inadequacy I have tried to give a complete list of references in the written text, so that the interested reader can pursue the points in depth (in particular see the review articles Parker, 1968a, 1969a, 1970). My purpose here is twofold, to outline for you the calculations and ideas that have developed thus far, and to indicate the uncertainties that remain. The basic ideas are sound, I think, but, when we come to the details, there are so many theoretical alternatives that need yet to be explored and so much that is not yet made clear by observations.

scholarly journals Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

2019 ◽  
Vol 5 (9) ◽  
pp. eaax3793 ◽  
Author(s):  
◽  
Q. An ◽  
R. Asfandiyarov ◽  
P. Azzarello ◽  
P. Bernardini ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Cosmic Radiation ◽  
Precise Measurement ◽  
Milky Way ◽  
Spectral Feature ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Proton Spectrum ◽  
First Time

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 1/2 years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

Supernova Remnants: An Introductory Review

2004 ◽  
Vol 218 ◽  
pp. 57-64
Author(s):  
Jacco Vink
Keyword(s):  
Cosmic Rays ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Cosmic Ray ◽  
Recent Advances ◽  
Cosmic Ray Acceleration ◽  
Introductory Review

The two main aspects of supernova remnant research addressed in this review are: I. What is our understanding of the progenitors of the observed remnants, and what have we learned from these remnants about supernova nucleosynthesis? II. Supernova remnants are probably the major source of cosmic rays. What are the recent advances in the observational aspects of cosmic ray acceleration in supernova remnants?

scholarly journals High energy cosmic ray interactions and UHECR composition problem

2019 ◽  
Vol 210 ◽  
pp. 02001
Author(s):  
Sergey Ostapchenko
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Hadronic Interactions ◽  
High Energy Cosmic Rays ◽  
Cosmic Ray Interactions ◽  
Composition Problem

The differences between contemporary Monte Carlo generators of high energy hadronic interactions are discussed and their impact on the interpretation of experimental data on ultra-high energy cosmic rays (UHECRs) is studied. Key directions for further model improvements are outlined. The prospect for a coherent interpretation of the data in terms of the UHECR composition is investigated.

scholarly journals Coincidence counter measurements of cosmic rays in an aeroplane

1936 ◽  
Vol 156 (889) ◽  
pp. 570-577 ◽  
Keyword(s):  
Cosmic Rays ◽  
High Altitude ◽  
Cosmic Ray ◽  
Independent Sets ◽  
Vertical Line ◽  
Coincidence Counting ◽  
Detailed Design ◽  
Recording Apparatus ◽  
Coincidence Counter ◽  
Balloon Experiments

Cosmic ray measurements on mountains are limited in general to altitudes below about 4000 meters. Above this height Regener has made successful use of small balloons carrying self-recording apparatus, and occasional flights have been made with manned balloons by Piccard, Cosyns, and by American workers. Balloon experiments are, however, hardly practicable in this country, so we decided to investigate cosmic rays, and in particular the production of showers, using an aeroplane. Facilities for flying to a height of about 10 km. Were generously provided by the Air Ministry. Apparatus Two independent sets of three tube counters were used in conjunction with the usual coincidence counting circuits. The counters could be arranged in a vertical line to record vertical penetrating particles, or in a triangle to record showers. The triple coincidences were recorded by telephone counters which were photographed at intervals together with a clock and aneroid barometer. The detailed design of the apparatus required some consideration since the aeroplane available (the Vickers Vespa machine used for high altitude experiments at the Royal Aircraft Establishment) had an open observer’s cockpit in which the counting set had to be installed.

The results of simultaneous measurements of the cosmic-ray intensity over the Antarctic and Arctic

1968 ◽  
Vol 46 (10) ◽  
pp. S823-S824
Author(s):  
S. N. Vernov ◽  
A. N. Charakhchyan ◽  
T. N. Charakhchyan ◽  
Yu. J. Stozhkov
Keyword(s):  
Cosmic Rays ◽  
Temperature Effects ◽  
Cosmic Ray ◽  
Primary Component ◽  
Low Energy ◽  
Cosmic Ray Intensity ◽  
Simultaneous Measurements ◽  
Murmansk Region ◽  
The Antarctic

The results of the analysis of data obtained from measurements carried out by means of regular stratospheric launchings of cosmic-ray radiosondes over the Murmansk region and the Antarctic observatory in Mirny in 1963–66 are presented. The problem of the anisotropy of the primary component of low-energy cosmic rays and of temperature effects on the cosmic-ray intensity in the atmosphere are discussed.

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