نتایج جستجو برای: cosmic equilibrium

تعداد نتایج: 160876  

Journal: :Physical review 2023

With insight from examples and physical arguments, the Tolman-Ehrenfest criterion of thermal equilibrium for test fluids in static spacetimes is extended to local conformally geometries. The temperature rescaled fluid scales with inverse conformal factor, reproducing evolution cosmic microwave background Friedmann universes, Hawking Sultana-Dyer cosmological black hole, a heuristic argument by ...

1998
P. M. W. Kalberla J. Kerp

The large scale distributions of gas, magnetic field and cosmic rays in the galactic halo are investigated. Our model is based on the analysis of all-sky surveys of H i gas (Lei-den/Dwingeloo survey), soft X-ray radiation (ROSAT all-sky survey), high energy γ-ray emission (EGRET > 100 MeV), and radio-continuum emission (408 MHz survey). We found a stable hydrostatic equilibrium configuration of...

2001
Carlos F. Sopuerta

Irrotational dust solutions of Einstein’s equations are suitable models to describe the general-relativistic aspects of the gravitational instability mechanism for the formation of cosmic structures. In this paper we study their state space by considering the local initial-value problem formulated in the covariant fluid approach. We consider a wide range of models, from homogeneous and isotropi...

1996
A. K. T. Assis M. C. D. Neves

We present the history of estimates of the temperature of intergalactic space. We begin with the works of Guillaume and Eddington on the temperature of interstellar space due to starlight belonging to our Milky Way galaxy. Then we discuss works relating to cosmic radiation, concentrating on Regener and Nernst. We also discuss Finlay-Freundlich’s and Max Born’s important research on this topic. ...

2015
Naoki YOSHIDA

Ongoing and future wide-field galaxy surveys can be used to locate a number of clusters of galaxies with cosmic shear measurement alone. We study constraints on cosmological models using statistics of weak lensing selected galaxy clusters. We extend our previous theoretical framework to model the statistical properties of clusters in variants of cosmological models as well as in the standard ΛC...

2002
Daniele Galli Malcolm Walmsley José Gonçalves

We have considered the thermal equilibrium in pre-protostellar cores in the approximation where the dust temperature is independent of interactions with the gas and where the gas is heated both by collisions with dust grains and ionization by cosmic rays. We have then used these results to study the stability of cores in hydrostatic equilibrium in the limit where thermal pressure dominates over...

2006
Orly Gnat

We present new computations of the equilibrium and non-equilibrium cooling efficiencies and ionization states for low-density radiatively cooling gas containing cosmic abundances of the elements H, He, C, N, O, Ne, Mg, Si, S, and Fe. We present results for gas temperatures between 10 and 10 K, assuming dust-free and optically thin conditions, and no external radiation. For non-equilibrium cooli...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید باهنر کرمان 1386

چکیده ندارد.

Hadi Hedayati Kh Maedeh Fazlalizadeh Mahmoud Bahmanabadi Mehdi Khakian Ghomi,

Geomagnetic field is a one of the candidates for creation of anisotropy in azimuth distribution of extensive air showers over the entered cosmic rays to the atmosphere. Here we present the question: Is there any azimuth anisotropy flux in the upper level of the atmosphere due to the geomagnetic field over the entered cosmic-rays? The obtained answer is: yes. This investigation showed an agreeme...

Journal: :iranian journal of astronomy and astrophysics 2014
mehdi khakian ghomi maedeh fazlalizadeh mahmoud bahmanabadi hadi hedayati kh

geomagnetic field is a one of the candidates for creation of anisotropy in azimuth distribution of extensive air showers over the entered cosmic rays to the atmosphere. here we present the question: is there any azimuth anisotropy flux in the upper level of the atmosphere due to the geomagnetic field over the entered cosmic-rays? the obtained answer is: yes. this investigation showed an agreeme...

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