Search results for "Cosmic"
showing 10 items of 656 documents
A New Numerical Approach to Estimate the Sunyaev–Zel’dovich Effect
2013
Several years ago, we designed a particular ray tracing method. Combined with a Hydra parallel code (without baryons), it may compute some CMB anisotropies: weak lensing (WL) and Rees–Sciama (RS) effects. Only dark matter is fully necessary to estimate these effects. For very small angular scales, we made an exhaustive study leading to a lensing contribution slightly—but significantly—greater than previous ones. Afterwards, the same ray tracing procedure was included in a parallel Hydra code with baryons. The resulting code was then tested. This code is being currently applied to the study of the thermal and kinetic Sunyaev–Zel’dovich (SZ) contributions to the CMB anisotropies. We present h…
The Palermo (Sicily) seismic cluster of September 2002, in the seismotectonic framework of the Tyrrhenian Sea-Sicily border area
2009
The northern coast of Sicily and its offshore area represent a hinge zone between a sector of the Tyrrhenian Basin, characterized by the strongest crustal thinning, and the sector of the Sicilian belt which has emerged. This hinge zone is part of a wider W-E trending right-lateral shear zone, which has been affecting the Maghrebian Chain units since the Pliocene. Seismological and structural data have been used to evaluate the seismotectonic behavior of the area investigated here. Seismological analysis was performed on a data set of about 2100 seismic events which occurred between January 1988 and October 2002 in the Southern Tyrrhenian Sea. This paper focuses…
Neutrino searches at the Pierre Auger Observatory
2013
Abstract The surface detector array of the Pierre Auger Observatory is sensitive to ultra-high energy neutrinos in the cosmic radiation. Neutrinos can interact in the atmosphere close to ground (down-going) and, for tau neutrinos, through the Earth-skimming mechanism (up-going) where a tau lepton is produced in the Earth crust that can emerge and decay in the atmosphere. Both types of neutrino-induced events produce an inclined particle air shower that can be identified by the presence of a broad time structure of signals in the water-Cherenkov detectors. We discuss the neutrino identification criteria used and present the corresponding limits on the diffuse and point-like source fluxes.
Measurement of the cosmic ray energy spectrum with IceTop-73
2013
Physical review / D 88(4), 042004 (2013). doi:10.1103/PhysRevD.88.042004
Deep-learning based reconstruction of the shower maximum X max using the water-Cherenkov detectors of the Pierre Auger Observatory
2021
The atmospheric depth of the air shower maximum $X_{\mathrm{max}}$ is an observable commonly used for the determination of the nuclear mass composition of ultra-high energy cosmic rays. Direct measurements of $X_{\mathrm{max}}$ are performed using observations of the longitudinal shower development with fluorescence telescopes. At the same time, several methods have been proposed for an indirect estimation of $X_{\mathrm{max}}$ from the characteristics of the shower particles registered with surface detector arrays. In this paper, we present a deep neural network (DNN) for the estimation of $X_{\mathrm{max}}$. The reconstruction relies on the signals induced by shower particles in the groun…
Observational constraints on the modelling of SN 1006
2011
Multi Parametric Advanced Research tool for meteo satellite data interfacing with space observation of Ultra High Energy Cosmic Rays.
2006
To approach the study of the cosmic rays in the energy range E > 10 20 eV, the upper end of the spectrum observed to date, with a large statistical significance (103 events/year), and hence address the solution of several astrophysical and cosmological problems related to their existence and behaviour, a new generation of experiments will probably have to be conceived and realised. They will be based on the observation and measurements of cosmic rays from space. The extremely low rate of these events (∼ 1 event/(century × km2 × sr)) imposes a very large effective area to be monitored, of the order of 105km2, as an observational requirement to meet the target statistics. The Extreme Universe…
<title>Studies of the activation background in CsI(Tl) detectors</title>
1993
CsI scintillation crystals are widely used as detection in (gamma) -ray astronomy observations. In the MeV energy region, one of the most important background sources in CsI is the (beta) decays induced in the crystal by cosmic ray protons and their secondaries. One recent idea for reducing this background is to use discrete detector arrays to reject the large amount of localized (beta) decay events. Two experiments were carried out with 1 cm3 CsI crystals bombarded with energetic proton beams and fast/thermal neutrons, with the aim of evaluating the effectiveness of this method in pixelated (1 cm3) CsI detectors. The ratio of the number of decays resulting in single site and multiple site …
Microscopic calculation of the $\beta^-$ decays of $^{151}$Sm, $^{171}$Tm, and $^{210}$Pb with implications to detection of the cosmic neutrino backg…
2023
The electron spectral shapes corresponding to the low-$Q$ $\beta^-$-decay transitions $^{151}$Sm$(5/2^-_{\rm g.s.})\to\,^{151}\textrm{Eu}(5/2^+_{\rm g.s.})$, $^{151}$Sm$(5/2^-_{\rm g.s.})\to\,^{151}\textrm{Eu}(7/2^+_{1})$, $^{171}$Tm$(1/2^+_{\rm g.s.})\to\,^{171}\textrm{Yb}(1/2^-_{\rm g.s.})$, $^{171}$Tm$(1/2^+_{\rm g.s.})\to\,^{171}\textrm{Yb}(3/2^-_{1})$, $^{210}\textrm{Pb}(0^+_{\rm g.s.})\to\,^{210}\textrm{Bi}(1^-_{\rm g.s.})$, and $^{210}\textrm{Pb}(0^+_{\rm g.s.})\to\,^{210}\textrm{Bi}(0^-_{1})$ have been computed using beta-decay theory with several refinements for these first-forbidden nonunique (ff-nu) $\beta^-$ transitions. These ff-nu $\beta^-$ transitions have non-trivial electro…
Tidal gravity observations at Mt. Etna and Stromboli: Results concerning the modeled and observed tidal factors
2009
Continuous gravity observations performed in the last few years, both at Mt. Etna and Stromboli, have prompted the need to improve the tidal analysis in order to acquire the best corrected data for the detection of volcano related signals. On Mt. Etna, the sites are very close to each other and the expected tidal factor differences are negligible. It is thus useful to unify the tidal analysis results of the different data sets in a unique tidal model. This tidal model, which can be independently confirmed by a modeling of the tidal parameters based on the elastic response of the Earth to tidal forces and the computation of the ocean tides effects on gravity, is very useful for the precise t…