نتایج جستجو برای: قطع gzk

تعداد نتایج: 7122  

Journal: :Monthly Notices of the Royal Astronomical Society 2021

ABSTRACT We study the clustering property and physical parameters of gzK-colour-selected star-forming galaxies (sgzKs) based on Canada–France–Hawaii Telescope surveys over 0.55 deg2 in AKARI North Ecliptic Pole-Deep Field. Two-point correlation functions for two magnitude-limited cases, Ks < 21.1 (N = 234) 21.5 428), are estimated using a single power-law function with fixed slope 0.8. T...

2002
D Palle

Cosmic ray events beyond the Greisen-Zatsepin-Kuzmin cutoff represent a great challenge for particle physics and cosmology. We show that the physics of heavy Majorana neutrinos, well defined by their masses, cross sections and lifetimes, could explain the highest energy cosmic rays as a consequence of the galactic annihilation of heavy neutrinos as cold dark matter particles. Galactic nuclei ac...

1998
Thomas J. Weiler

If neutrinos are a significant contributor to the matter density of the universe, then they should have ∼ eV mass and cluster in galactic (super) cluster halos, and possibly in galactic halos as well. It was noted in the early 1980’s that cosmic ray neutrinos with energy within δE/ER = ΓZ/MZ ∼ 3% of the peak energy ER = 4 (eV/mν)× 1021 eV will annihilate on the nonrelativistic relic antineutrin...

Journal: :Chemosphere 2009
Zachary Getenga Ulrike Dörfler Azuka Iwobi Michael Schmid Reiner Schroll

A tropical soil from a Kenyan sugarcane-cultivated field showed a very high capability to mineralize (14)C-ring-labeled atrazine. In laboratory experiments this soil mineralized about 90% of the applied atrazine within 98 d. The atrazine-degrading microbial community was enriched in liquid cultures containing atrazine as the sole N source and 100 mgL(-1) glucose as additional C source. From the...

2007
Vitor de Souza

The measurement of the ultra high energy cosmic ray (UHECR) spectrum is strongly affected by uncertainties on the reconstructed energy. The determination of the presence or absence of the GZK cutoff and its position in the energy spectrum depends not only on high statistics but also on the shape of the energy error distribution. Here we determine the energy error distribution for fluorescence t...

Journal: :The Astrophysical journal 2000
de Gouveia Dal Pino EM Lazarian

We here investigate the possibility that the ultra-high-energy cosmic-ray (UHECR) events observed above the Greisen-Zatsepin-Kuzmin (GZK) limit are mostly protons accelerated in reconnection sites just above the magnetosphere of newborn millisecond pulsars that are originated by accretion-induced collapse (AIC). We formulate the requirements for the acceleration mechanism and show that AIC puls...

2008
Ivone F. M. Albuquerque George F. Smoot

The development of an ultra high energy air shower has an intrinsic energy fluctuation due both to the first interaction point and to the cascade development. Here we show that for a given primary energy this air shower energy fluctuation has a lognormal distribution and thus observations will estimate that primary energy with a lognormal error distribution. We analyze the UHECR energy spectrum...

2011
Igor Tkachev

In this talk I present resent results on high energy cosmic rays, including energy spectra, composition and the study of arrival directions of cosmic ray primaries. Some related results in gamma-ray astronomy and selected recent advances in theory are also covered. c ⃝ Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. The ques...

2008
D. Fargion P. Oliva F. Massa G. Moreno

Multi-GeV and TeVs gamma sources are currently observed by their Cherenkov flashes on Telescopes (as Magic, Hess and Veritas), looking vertically up into sky. These detectors while pointing horizontally should reveal also the fluorescence flare tails of nearby down-going airshowers. Such airshowers, born at higher (tens km) altitudes, are growing and extending up to lowest atmospheres (EeVs) or...

2000
Michael Blanton Angela V. Olinto

We calculate numerically the spectrum of ultra-high energy cosmic rays on Earth assuming that their sources are distributed in space like the observed galaxies. We use the CfA2 and the PSCz galaxy redshift surveys to model the local galaxy distribution, properly taking into account the galaxy selection functions for each survey. When the survey selection effects are included, we find that the l...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید