758 research outputs found
The gamma-ray and neutrino sky: A consistent picture of Fermi-LAT, Milagro, and IceCube results
We compute the gamma-ray and neutrino diffuse emission of the Galaxy on the
basis of a recently proposed phenomenological model characterized by radially
dependent cosmic-ray (CR) transport properties. We show how this model,
designed to reproduce both Fermi-LAT gamma-ray data and local CR observables,
naturally reproduces the anomalous TeV diffuse emission observed by Milagro in
the inner Galactic plane. Above 100 TeV our picture predicts a neutrino flux
that is about five (two) times larger than the neutrino flux computed with
conventional models in the Galactic Center region (full-sky). Explaining in
that way up to of the flux measured by IceCube, we reproduce the
full-sky IceCube spectrum adding an extra-Galactic component derived from the
muonic neutrino flux in the northern hemisphere. We also present precise
predictions for the Galactic plane region where the flux is dominated by the
Galactic emission.Comment: 5 pages, 3 figure
Gamma-ray and neutrino diffuse emissions of the Galaxy above the TeV
As recently shown, Fermi-LAT measurements of the diffuse gamma-ray emission
from the Galaxy favor the presence of a smooth softening in the primary
cosmic-ray spectrum with increasing Galactocentric distance. This result can be
interpreted in terms of a spatial-dependent rigidity scaling of the diffusion
coefficient. The DRAGON code was used to build a model based on such feature.
That scenario correctly reproduces the latest Fermi-LAT results as well as
local cosmic-ray measurements from PAMELA, AMS-02 and CREAM. Here we show that
the model, if extrapolated at larger energies, grasps both the gamma-ray flux
measured by MILAGRO at 15 TeV and the H.E.S.S. data from the Galactic ridge,
assuming that the cosmic-ray spectral hardening found by those experiments at
about 250 GeV/n is present in the whole inner Galactic plane region. Moreover,
we show as that model also predicts a neutrino emission which may account for a
significant fraction, as well as for the correct spectral shape, of the
astrophysical flux measured by IceCube above 25 TeV.Comment: Oral contribution to the 34th International Cosmic Ray Conference,
July 30 to August 6, The Hague, Netherland
A Hadronic Scenario for the Galactic Ridge
Several observations from Fermi-LAT, up to few hundred GeV, and from
H.E.S.S., up to 10 TeV, reported an intense -ray emission from
the inner part of the Galactic plane. After the subtraction of point-like
contributions, the remaining -ray spectrum can provide important hints
about the cosmic-ray (CR) population in that region. In particular, the diffuse
spectrum measured by both Fermi-LAT and H.E.S.S. in the Galactic Ridge is
significantly harder with respect to the rest of the Galaxy. These results were
recently interpreted in terms of a comprehensive CR transport model which,
adopting a spatial dependent diffusion coefficient and convective velocity,
reproduces Fermi-LAT results on the whole sky as well as local CR spectra. We
showed as that model predicts a significantly harder neutrino diffuse emission
compared to conventional scenarios: The predicted signal is able to account for
a significant fraction of the astrophysical flux measured by IceCube. In this
contribution, we use the same setup to calculate the expected neutrino flux
from several windows in the inner Galactic plane and compare the results with
IceCube observations and the sensitivities of Mediterranean neutrino
telescopes. In particular, for the ANTARES experiment, we compare the model
expectations with the upper limits obtained from a recent unblinded
data-analysis focused on the galactic ridge region. Moreover, we also show the
expectations from the galactic ridge for the future KM3NeT observatory, whose
position is optimal to observe this portion of the sky.Comment: Oral contribution to the 34th International Cosmic Ray Conference,
July 30 to August 6, The Hague, Netherland
Interpretation of astrophysical neutrinos observed by IceCube experiment by setting Galactic and extra-Galactic spectral components
The last IceCube catalog of High Energy Starting Events (HESE) obtained with
a livetime of 1347 days comprises 54 neutrino events equally-distributed
between the three families with energies between 25 TeV and few PeVs.
Considering the homogeneous flavors distribution (1:1:1) and the spectral
features of these neutrinos the IceCube collaboration claims the astrophysical
origin of these events with more than . The spatial distribution of
cited events does not show a clear correlation with known astrophysical
accelerators leaving opened both the Galactic and the extra-Galactic origin
interpretations. Here, we compute the neutrino diffuse emission of our Galaxy
on the basis of a recently proposed phenomenological model characterized by
radially-dependent cosmic-ray (CR) transport properties. We show that the
astrophysical spectrum measured by IceCube experiment can be well explained
adding to the diffuse Galactic neutrino flux (obtained with this new model) a
extra-Galactic component derived from the astrophysical muonic neutrinos
reconstructed in the Northern hemisphere. A good agreement between the expected
astrophysical neutrino flux and the IceCube data is found for the full sky as
well as for the Galactic plane region.Comment: 4 pages, 2 figures, accepted for the VLVnT-2015 Conference
proceeding
Tensor and tensor-isospin terms in the effective Gogny interaction
We discuss the need of including tensor terms in the effective Gogny
interaction used in mean-field calculations. We show in one illustrative case
that, with the usual tensor term that is employed in the Skyrme interaction
(and that allows us to separate the like-nucleon and the neutron-proton tensor
contributions), we can describe the evolution of the N=28 neutron gap in
calcium isotopes. We propose to include a tensor and a tensor-isospin term in
finite-range interactions of Gogny type. The parameters of the two tensor terms
allow us to treat separately the like-nucleon and the neutron-proton
contributions. Two parameterizations of the tensor terms have been chosen to
reproduce different neutron single-particle properties in the 48Ca nucleus and
the energy of the first 0- state in the 16O nucleus. By employing these two
parameterizations we analyze the evolution of the N=14, 28, and 90 neutron
energy gaps in oxygen, calcium and tin isotopes, respectively. We show that the
combination of the parameters governing the like-nucleon contribution is
crucial to correctly reproduce the experimental (where available) or
shell-model trends for the evolution of the three neutron gaps under study.Comment: 20 pages, 6 figures. Accepted for publication in Physical Review
Site Response Analysis in the STM-M6 Industrial Area of the City of Catania (Italy)
The paper presents the case history of the geotechnical characterization of a seismic site for the re-use of an industrial building for producing solar panels in the industrial area of Catania (Sicily, Italy). To determine the geological profile and the geotechnical characteristics of the soil, the site was well investigated by means of in situ and laboratory tests. The following in situ geotechnical tests were carried out: Borings, SPT, CPT, PLT and dynamic in situ tests. Among them Down-Hole (D-H), Cross-Hole (C-H), SASW and recently Seismic Dilatometer Marchetti Tests (SDMT) have been carried out, with the aim to evaluate the soil profile of shear waves velocity (Vs). Moreover the following laboratory tests were carried out on undisturbed samples retrieved with a 86 mm diameter Shelby sampler: Oedometer tests, Direct shear tests, Resonant Column and Torsional shear tests. Static and dynamic parameters obtained by in situ and laboratory tests were reported and analyzed. Moreover the Sicilian earthquake of December 13, 1990 (ML= 5.4) heavy damaged the site, also due to soil amplification. Using the recordings of this earthquake, to evaluate the input motion at the conventional bedrock, the ground response analysis has been obtained by the 1-D non-linear code EERA at the industrial building site. In particular the study has regarded the evaluation of site effects in terms of acceleration time history at the surface, soil amplification factors, as well as in terms of time history and response spectra
Use of peas in organic buffalo farming: effects on nutrient digestibility and milk production
Twenty lactating buffalo cows, organically farmed, were used to examine the effects of including peas in total mixed ration. Two concentrates were formulated to contain, as the main protein sources, either 350 g/kg of soybean cake (CC) or 450 g/kg of peas (ExpC). Cows were blocked into two groups according to parity and previous milk yield and were assigned to one of two dietary treatments: one group was fed a diet with 6 kg/d of CC, whereas the treatment group was fed diet in which 3kg/d of CC were replaced by an equal quantity of ExpC. Digestibility of the diets and milk production of the cows were measured. The experimental period covered the whole lactation period. No differences were observed between groups for milk yield and composition, and for total tract apparent digestibility. The main hypothesis tested, that the replacement of soybean cake with peas in buffalo diet would not affect milk yield and composition, was confirmed. This suggested that the partial substitution of soybean cake with peas in diet for buffalo cows can be possible without affect performances
Topographic Site Effects Evaluation for the Monte Po Hill in the City of Catania (Italy)
The Monte Po Hill is located in the North-eastern part of the city of Catania; this area is prone to high seismic risk due to the presence of several constructions, including a school, in the vicinity of a toe of a slope, characterized by precarious stability conditions. The study has regarded the evaluation of site effects in correspondence of the site, to which corresponds a different value of the Seismic Geotechnical Hazard. In the beginning of 2007 a seismic station has been also located into the school building, with the aim of recording seismic events. Seismograms obtained by the seismic station have been also used to evaluate the ground response analysis at the surface. Finally the 1-D computer code EERA was also used to model the equivalent-linear earthquake site response analyses of layered soil deposits of the hill. The detail with which the hill has been studied has allowed the construction of a detailed 2-D model of its structure. It has been explored the differences between the computed ground motion for different Vs profiles using QUAD4M and QUAKE/W 2-D codes. It has been also possible to compare the results from different 1-D models reflecting current approaches to the determination of site response
Dynamic Geotechnical Characterization of San Giuliano Di Puglia Seismic Area
The city of San Giuliano di Puglia (CB), located in the Molise region in Southern Italy, is prone to high seismic risk. For site characterisation of soil deep site investigations have been undertaken. Borings, static and dynamic in situ tests have been performed. Among them Cone Penetration Tests (CPT), Cross-Hole (C-H) Down-Hole (D-H) and Seismic Dilatometer Marchetti Tests (SDMT) have been carried out, with the aim to evaluate the soil profile of shear waves velocity (Vs). Moreover the following laboratory tests were carried out on undisturbed samples: Oedometer tests, undrained Triaxial tests and Resonant Column tests. The available data enabled one to compare the shear waves velocity profile obtained by empirical correlations, Down Hole tests and Seismic Dilatometer Marchetti Tests. The influence of strain level on G-γ and D-γ curves was evaluated by means of laboratory tests. Two expression to allows the complete shear modulus degradation with strain level and the inverse variation of damping ratio with normalized shear modulus respectively were proposed. Finally after evaluating the synthetic accelerograms at the bedrock, the ground response analysis at the surface, in terms of time history and response spectra, has been obtained by two non-linear models GEODIN and EERA
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