Related papers: Maximum brightness temperature for an incoherent s…
Based on definitions, two joint-criteria, namely, the optical-thin constraint and the energy budget constraint, are proposed to judge whether the emission nature of radio pulsars is incoherent or obligatory to be coherent. We find that the…
Synchrotron radiation mechanism, when electrons are accelerated in a relativistic shock, is known to have serious problems to explain the observed gamma-ray spectrum below the peak for most Gamma-Ray Bursts (GRBs); the synchrotron spectrum…
Inhomogeneities in a synchrotron source can severely affect the conclusions drawn from observations regarding the source properties. However, their presence is not always easy to establish, since several other effects can give rise to…
In this paper we estimated the temperatures and brightnesses of the Monoceros radio loop at 1420, 820 and 408 MHz. Linear spectrum is estimated for mean temperatures versus frequency between 1420, 820 and 408 MHz. The spectral index of…
Absorption or emission against the cosmic microwave background radiation (CMB) may be observed in the redshifted 21cm line if the spin temperature of the neutral intergalactic medium prior to reionization differs from the CMB temperature.…
New upper limit on a mixing parameter for hidden photons with a mass from 5 eV till 10 keV has been obtained from the results of measurements during 78 days in two configurations R1 and R2 of a multicathode counter. For a region of a…
A self-consistent approach to nonequilibrium radiation temperature is introduced using the distribution of the energy over states. We begin rigorously with ensembles of Hilbert spaces and end with practical examples based mainly on the far…
We show, in different ways, that in the ubiquitous phenomenon of black body radiation there exists a minimum and maximum temperature. These limiting values are so small and large respectively, that they are of no practical use, except in an…
A relationship between the maximum operating temperature of semiconductor lasers and their emission wavelength is conjectured. The conjecture is supported by a wide variety of existing experimental data for visible and infrared double…
The 21 cm signatures induced by moving cosmic string loops are investigated. Moving cosmic string loops seed filamentary nonlinear objects. We analytically evaluate the differential 21 cm brightness temperature from these objects. We show…
This paper reports the first discovery of possible inverse Compoton (IC) X-ray emission below 10 keV in the typical high-energy peaked BL Lac object (HBL) PKS 2155--304. Two XMM-Newton observations performed in 2006 reveal that the 0.6--10…
We determine the limit of the lowest achievable photoemitted electron temperature, and therefore the maximum achievable electron brightness, due to heating just after emission into vacuum, applicable to dense relativistic or nonrelativistic…
We study $e^{\pm}$ pair plasmas in pair equilibrium, which emit high energy radiation by thermal Comptonization of soft photons. We find that the maximum luminosity to size ratio of the source (i.e. the compactness) depends not only on the…
Comparing the asymmetry coefficients and scintillation indices for observed time variations of the intensity of the radiation of extragalactic sources and the predictions of theoretical models is a good test of the nature of the observed…
The Universe owns the electronic radiation of blackbody at temperature 2.725 K, which we call the cosmic electron background. We calculate its radiation spectrum. The energy distribution of number density of electrons in the cosmic electron…
X-ray observations of the binary pulsar GX 1+4 made using the Rossi X-ray Timing Explorer (RXTE) satellite between February 1996 and May 1997 were analysed to quantify source spectral variation with luminosity. Mean Proportional Counter…
We use the radio-infrared (IR) flux correlation bet ween star-forming galaxies in the local universe to derive a simple analytical expression between the intensity of the IR background and the brightness t emperature of the radio…
The radio sky is poorly sampled for rapidly varying transients because of the narrow field-of-view of most imaging radio telescopes at cm and shorter wavelengths. The emergence of sensitive long wavelength observations with intrinsically…
Relativistic electrons, seen in the large diffuse radio halo of the Coma cluster of galaxies, should scatter background photons to higher energies. We calculate the inverse Compton contributions from the microwave background, from the local…
We study models in which the universe exits reheating at temperatures in the MeV regime. By combining light element abundance measurements with cosmic microwave background and large scale structure data we find a fairly robust lower limit…