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The Relative Expansion of the Universe
Issue:
Volume 3, Issue 3, May 2015
Pages:
37-39
Received:
3 March 2015
Accepted:
12 April 2015
Published:
27 April 2015
Abstract: This is an alternate explanation to the redshift effect and increasing distance between galaxies. Everything in the universe excluding empty space is shrinking, including elementary particles. In contrast to everything else, the empty space would appear to be expanding. This idea is compatible with most of established science, such as the theory of relativity, the doppler effect, the big rip idea. And, it also helps explain dark energy. An idea that is not very well understood yet.
Abstract: This is an alternate explanation to the redshift effect and increasing distance between galaxies. Everything in the universe excluding empty space is shrinking, including elementary particles. In contrast to everything else, the empty space would appear to be expanding. This idea is compatible with most of established science, such as the theory of...
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On Jet Opening Angle and Dynamical Evolution of Some Powerful Extragalactic Radio Sources
Ezeugo Jeremiah Chukwuemerie
Issue:
Volume 3, Issue 3, May 2015
Pages:
40-43
Received:
26 March 2015
Accepted:
15 April 2015
Published:
30 April 2015
Abstract: We used both analytical and statistical methods of analyses to find out if there is possible connection between jet opening solid angle and linear size evolution of some powerful extragalactic radio sources in our sample. Based on simple linear regression analyses of D-Ω data (where D is observed linear size and Ω is estimated jet opening solid angle), we found with a marginal correlation, that effects contributed by the opening angle may be overshadowed by other factors. A plausible interpretation of the result is that there is presence of appreciable ambient gases around these sources.
Abstract: We used both analytical and statistical methods of analyses to find out if there is possible connection between jet opening solid angle and linear size evolution of some powerful extragalactic radio sources in our sample. Based on simple linear regression analyses of D-Ω data (where D is observed linear size and Ω is estimated jet opening solid ang...
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An Analytical Estimate of the Hubble Constant
Issue:
Volume 3, Issue 3, May 2015
Pages:
44-49
Received:
19 March 2015
Accepted:
31 March 2015
Published:
27 April 2015
Abstract: Currently the present-time value of the Hubble constant is estimated through finding the optimum fit to the observationally measured data. Here, assuming a flat universe with zero cosmological constant, based on the conservation of total mass-energy and a correction for the effect of time dilation, the total present-time value of the energy density parameter is found to be equal to 0.703091. Based on the Friedmann-Robertson-Walker (FRW) equation, the first law of thermodynamics, and Einstein’s Equivalence Principle, we present an analytical approach which yields a value for the Hubble constant equal to H_0=69.05398 km s^(-1) 〖Mpc〗^(-1). Using this value, Hubble diagrams are constructed. These diagrams are remarkably consistent with the available observational data.
Abstract: Currently the present-time value of the Hubble constant is estimated through finding the optimum fit to the observationally measured data. Here, assuming a flat universe with zero cosmological constant, based on the conservation of total mass-energy and a correction for the effect of time dilation, the total present-time value of the energy density...
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Stability of Charged Shell Supported by a Phantom Energy
Issue:
Volume 3, Issue 3, May 2015
Pages:
50-55
Received:
23 April 2015
Accepted:
6 May 2015
Published:
15 May 2015
Abstract: This paper discusses the evolution of a thin spherically symmetric self gravitating phantom shell around the charged shell. The general equations describing the motion of shell with a general form of equation of state are derived. The different types of space-time R± and T± regions and shell motion are classified depending on the parameters of the problem. The mechanical stability analysis of this spherically symmetric thin shell with charge in Reissner- Nordstrom (RN) to linearized spherically symmetric perturbation about static equilibrium solution is carried out.
Abstract: This paper discusses the evolution of a thin spherically symmetric self gravitating phantom shell around the charged shell. The general equations describing the motion of shell with a general form of equation of state are derived. The different types of space-time R± and T± regions and shell motion are classified depending on the parameters of the ...
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Fluctuations of Solar Wind Parameters During Polar Reversal
Iren Sobia,
Bidhu S. S.,
Dickson Benjamin
Issue:
Volume 3, Issue 3, May 2015
Pages:
56-62
Received:
9 April 2015
Accepted:
1 May 2015
Published:
19 May 2015
Abstract: Around the time of polarity reversal in 2000 – 2001, the solar wind plasma parameters and interplanetary magnetic field fluctuations are studied for an interval of time that corresponds to Ulysses in-situ measurements of high-latitude heliospheric magnetic field. This study has been done by investigating solar wind speed, density, temperature and solar magnetic field using Ulysses magnetometer and SWOOPS instrument. The sun's magnetic field reverses polarity approximately in every 11 year and it creates a peak in each solar cycle. This study gives a brief understanding of solar wind parameters in the heliosphere during polar reversal in solar cycle 23. The solar magnetic field completely reorganizes during the polar reversal phase, hence the distribution of solar wind parameters changes accordingly. By studying the variation of solar wind parameters, it is possible to understand the polar reversal phenomenon. The photospheric polarity reversal is completed in more active Northern Hemisphere in late 2000 and then in the Southern Hemisphere in 2001. The reversal of the magnetic field at the solar wind source surface is inferred to have occurred between late 2000 and 2001, with the most likely time of reversal being early within that period.
Abstract: Around the time of polarity reversal in 2000 – 2001, the solar wind plasma parameters and interplanetary magnetic field fluctuations are studied for an interval of time that corresponds to Ulysses in-situ measurements of high-latitude heliospheric magnetic field. This study has been done by investigating solar wind speed, density, temperature and s...
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A Method to Estimate the Cooling Time of Ultra-Relativistic Electrons in Pulsar Wind Nebulae
K. L. I. Gunawardhana,
K. P. S. C. Jayaratne,
J. Adassuriya
Issue:
Volume 3, Issue 3, May 2015
Pages:
63-69
Received:
24 February 2015
Accepted:
1 May 2015
Published:
27 May 2015
Abstract: Pulsar is a highly magnetized rotating neutron star. It continuously emits a wind of relativistic electrons and positrons. This wind creates an electron-positron-cloud around the pulsar. This cloud, which is full of relativistic electrons and positrons, is called a Pulsar Wind Nebula (PWN). As of 2014, 33 Pulsar Wind Nebulae (PWNe) have been detected in the TeV energy band. Current understanding is, these TeV photons are produced from up-scattering low-energy photons to high-energies by ultra-relativistic electrons and positrons in PWNe, which is a non-thermal process. This process is known as inverse-Compton scattering. During inverse-Compton scattering, ultra-relativistic electrons lose their energy and cool-down to low-energies. The average time that an ultra-relativistic electron takes to cool-down by inverse-Compton scattering is called the cooling time. Estimation of cooling time is important to understand how the luminosity of a PWN changes with time. This paper describes a statistical method developed for estimating the cooling time of ultra-relativistic electrons in a given PWN. This new method is a model independent technique. Cooling time was estimated as a function of two parameters: k and γ. Here k is the high-energy electron fraction in PWN at a given time and γ is the Average Bulk Lorentz Factor of electrons in the PWN. The estimated cooling time is proportional to k and inversely proportional to γ. The developed method was applied to four PWNe: MSH 15-52, HESS J1420-607, HESS J1825-137 and HESS J1837-069. The estimated cooling times vary between 1.56 kyr to 1000 kyr for MSH 15-52, 13 kyr to 8000 kyr for HESS J1420-607, 21.4 kyr to 10000 kyr for HESS J1825-137 and 22.7 kyr to 15000 kyr for HESS J1837-069.
Abstract: Pulsar is a highly magnetized rotating neutron star. It continuously emits a wind of relativistic electrons and positrons. This wind creates an electron-positron-cloud around the pulsar. This cloud, which is full of relativistic electrons and positrons, is called a Pulsar Wind Nebula (PWN). As of 2014, 33 Pulsar Wind Nebulae (PWNe) have been detect...
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