Propagation and nucleosynthesis of ultraheavy cosmic rays

The observed fluxes of cosmic ray (C.R.) ultraheavy elements depend on their charge and mass spectrum at the sources and on the propagation effects, on the distribution of path lengths traversed by the particles on their way from the sources to the observation point. The effect of different path length distributions (p.l.d.) on the infered source abunances is analyzed. It seems that it is rather difficult to fit a reasonable p.l.d. so that the obtained source spectrum coincides with the Solar System (SS) abundances in more detail. It suggests that the nucleosynthesis conditions for c.r. nuclei may differ from that for SS matter. The nucleosynthesis of ultraheavy elements fitting its parameters to get the c.r. source abundances is calculated. It is shown that it is possible to get a very good agreement between the predicted and the observed source abundance

Secondary to primary ratio and the continuous acceleration

A general formula for the sec/prim ratio, independently of any details of the propagation and acceleration model is presented. In the limit of equal fragmentation paths for primaries and secondaries, this ratio at a given momentum nucleon is proportional only to the mean path of the observed primaries at that moment. It is shown that it is unlikely to get a decreasing sec/prim ratio with energy if an acceleration process takes place during particle propagation in the interstellar medium (ISM)

Cosmic-ray measurements by reconstructing longitudinal profiles for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory in the energy range from 20 GeV to 300 TeV, offering 5-10 times better flux sensitivity than the current generation of imaging atmospheric Cherenkov telescopes. Each telescope will capture an image of the Cherenkov light produced when air showers created by gamma rays or cosmic rays pass through the atmosphere. The longitudinal development of the shower in the atmosphere can be studied by measuring the number of charged particles produced as a function of depth. The reconstruction of the longitudinal shower profile provides the depth of the shower maximum Xmax which is a mass-sensitive parameter useful for cosmic ray composition. In this work, we reconstruct the longitudinal profile and the Xmax of air showers initiated by two kinds of cosmic ray species, proton, and iron, with energies between 10 TeV and 300 TeV. This reconstruction is different from other methods that have been used in the past as template-based fit techniques that require a detailed and computing-intensive simulation chain. In contrast, we use for the first time a parameterized function for the angular distribution of Cherenkov light around the shower axis.</p

Cosmic-ray measurements by reconstructing longitudinal profiles for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory in the energy range from 20 GeV to 300 TeV, offering 5-10 times better flux sensitivity than the current generation of imaging atmospheric Cherenkov telescopes. Each telescope will capture an image of the Cherenkov light produced when air showers created by gamma rays or cosmic rays pass through the atmosphere. The longitudinal development of the shower in the atmosphere can be studied by measuring the number of charged particles produced as a function of depth. The reconstruction of the longitudinal shower profile provides the depth of the shower maximum Xmax which is a mass-sensitive parameter useful for cosmic ray composition. In this work, we reconstruct the longitudinal profile and the Xmax of air showers initiated by two kinds of cosmic ray species, proton, and iron, with energies between 10 TeV and 300 TeV. This reconstruction is different from other methods that have been used in the past as template-based fit techniques that require a detailed and computing-intensive simulation chain. In contrast, we use for the first time a parameterized function for the angular distribution of Cherenkov light around the shower axis.</p

Cosmic-ray measurements by reconstructing longitudinal profiles for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory in the energy range from 20 GeV to 300 TeV, offering 5-10 times better flux sensitivity than the current generation of imaging atmospheric Cherenkov telescopes. Each telescope will capture an image of the Cherenkov light produced when air showers created by gamma rays or cosmic rays pass through the atmosphere. The longitudinal development of the shower in the atmosphere can be studied by measuring the number of charged particles produced as a function of depth. The reconstruction of the longitudinal shower profile provides the depth of the shower maximum Xmax which is a mass-sensitive parameter useful for cosmic ray composition. In this work, we reconstruct the longitudinal profile and the Xmax of air showers initiated by two kinds of cosmic ray species, proton, and iron, with energies between 10 TeV and 300 TeV. This reconstruction is different from other methods that have been used in the past as template-based fit techniques that require a detailed and computing-intensive simulation chain. In contrast, we use for the first time a parameterized function for the angular distribution of Cherenkov light around the shower axis.</p

Ultra-high energy cosmic rays may come from clustered sources

Clustering of cosmic-ray sources affects the flux observed beyond the cutoff imposed by the cosmic microwave background and may be important in interpreting the AGASA, Fly's Eye, and HiRes data. The standard deviation, sigma, in the predicted number, N, of events above 10^{20} eV is sigma/N = 0.9(r_0/10 Mpc)^{0.9}, where r_0 is the unknown scale length of the correlation function (r_0 = 10 Mpc for field galaxies). Future experiments will allow the determination of r_0 through the detection of anisotropies in arrival directions of ~ 10^{20} eV cosmic-rays over angular scales of Theta ~ r_0/30 Mpc.Comment: Accepted for publication in Astrophysical Journa

Cosmic-ray measurements by reconstructing longitudinal profiles for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory in the energy range from 20 GeV to 300 TeV, offering 5-10 times better flux sensitivity than the current generation of imaging atmospheric Cherenkov telescopes. Each telescope will capture an image of the Cherenkov light produced when air showers created by gamma rays or cosmic rays pass through the atmosphere. The longitudinal development of the shower in the atmosphere can be studied by measuring the number of charged particles produced as a function of depth. The reconstruction of the longitudinal shower profile provides the depth of the shower maximum Xmax which is a mass-sensitive parameter useful for cosmic ray composition. In this work, we reconstruct the longitudinal profile and the Xmax of air showers initiated by two kinds of cosmic ray species, proton, and iron, with energies between 10 TeV and 300 TeV. This reconstruction is different from other methods that have been used in the past as template-based fit techniques that require a detailed and computing-intensive simulation chain. In contrast, we use for the first time a parameterized function for the angular distribution of Cherenkov light around the shower axis.</p

Cosmic-ray measurements by reconstructing longitudinal profiles for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory in the energy range from 20 GeV to 300 TeV, offering 5-10 times better flux sensitivity than the current generation of imaging atmospheric Cherenkov telescopes. Each telescope will capture an image of the Cherenkov light produced when air showers created by gamma rays or cosmic rays pass through the atmosphere. The longitudinal development of the shower in the atmosphere can be studied by measuring the number of charged particles produced as a function of depth. The reconstruction of the longitudinal shower profile provides the depth of the shower maximum Xmax which is a mass-sensitive parameter useful for cosmic ray composition. In this work, we reconstruct the longitudinal profile and the Xmax of air showers initiated by two kinds of cosmic ray species, proton, and iron, with energies between 10 TeV and 300 TeV. This reconstruction is different from other methods that have been used in the past as template-based fit techniques that require a detailed and computing-intensive simulation chain. In contrast, we use for the first time a parameterized function for the angular distribution of Cherenkov light around the shower axis.</p

Water Quality of the Poza Honda Dam and Other Water Points Down

The phenomenon of pollution of water basins is eliminating many potential water resources. Most of the pollution in Ecuador comes from household waste and agricultural chemicals, especially along the coast. One of the activities in the management of the water resource is the periodic monitoring of the bodies of water, being able to determine the different changes that occur and to influence through preventive actions that manage to reduce the pollution. The water resource is the articulating axis of all the activities in a territory and therefore of the populations that develop different productive activities that not only depend on the quantity and quality of this resource but also generate alterations to the natural state of the same. In the investigation, the monitoring of the quality of the water in different points of the Poza Honda dam and of the river Portoviejo is carried out. The study aims to manage the pollution processes that occur in the aquifer, due to the depositions of domestic, industrial and agricultural wastewater not controlled to be discharged

The energy production rate & the generation spectrum of UHECRs

We derive simple analytic expressions for the flux and spectrum of ultra-high energy cosmic-rays (UHECRs) predicted in models where the CRs are protons produced by extra-Galactic sources. For a power-law scaling of the CR production rate with redshift and energy, d\dot{n} /dE\propto E^-\alpha (1+z)^m, our results are accurate at high energy, E>10^18.7 eV, to better than 15%, providing a simple and straightforward method for inferring d\dot{n}/dE from the observed flux at E. We show that current measurements of the UHECR spectrum, including the latest Auger data, imply E^2d\dot{n}/dE(z=0)=(0.45\pm0.15)(\alpha-1) 10^44 erg Mpc^-3 yr^-1 at E<10^19.5 eV with \alpha roughly confined to 2\lesseq\alpha<2.7. The uncertainty is dominated by the systematic and statistic errors in the experimental determination of individual CR event energy, (\Delta E/E)_{sys} (\Delta E/E)_{stat} ~20%. At lower energy, d\dot{n}/dE is uncertain due to the unknown Galactic contribution. Simple models in which \alpha\simeq 2 and the transition from Galactic to extra-Galactic sources takes place at the "ankle", E ~10^19 eV, are consistent with the data. Models in which the transition occurs at lower energies require a high degree of fine tuning and a steep spectrum, \alpha\simeq 2.7, which is disfavored by the data. We point out that in the absence of accurate composition measurements, the (all particle) energy spectrum alone cannot be used to infer the detailed spectral shapes of the Galactic and extra-Galactic contributions.Comment: 9 pages, 11 figures, minor revision