167 research outputs found
La primera Conferencia Latinoamericana sobre Entrenamiento en PsicologĂa (1974): el modelo Latinoamericano y su significaciĂłn histĂłrica
Study of the Very High Energy emission of M87 through its broadband spectral energy distribution
The radio galaxy M87 is the central dominant galaxy of the Virgo Cluster.Very High Energy (VHE, TeV) emission, from M87 has been detectedby Imaging Air Cherenkov Telescopes (IACTs ). Recently, marginal evidence forVHE long-term emission has also been observed by the High Altitude WaterCherenkov (HAWC) Observatory, a gamma ray and cosmic-ray detector array locatedin Puebla, Mexico. The mechanism that produces VHE emission in M87 remainsunclear. This emission is originated in its prominent jet, which has beenspatially resolved from radio to X-rays. In this paper, we constructed aspectral energy distribution from radio to gamma rays that is representative ofthe non-flaring activity of the source, and in order to explain the observedemission, we fit it with a lepto-hadronic emission model. We found that thismodel is able to explain non-flaring VHE emission of M87 as well as an orphanflare reported in 2005.<br
Gamma-ray Emission from Classical Nova V392 Per: Measurements from Fermi and HAWC
This paper reports on the -ray properties of the 2018 Galactic novaV392 Per, spanning photon energies 0.1 GeV to 100 TeV by combiningobservations from the Fermi Gamma-ray Space Telescope and the HAWC Observatory.In one of the most rapidly evolving -ray signals yet observed for anova, GeV rays with a power law spectrum with index were detected over eight days following V392 Per's optical maximum. HAWCobservations constrain the TeV -ray signal during this time and alsobefore and after. We observe no statistically significant evidence of TeV-ray emission from V392 Per, but present flux limits. Tests of theextension of the Fermi/LAT spectrum to energies above 5 TeV are disfavored by 2standard deviations (95\%) or more. We fit V392 Per's GeV rays withhadronic acceleration models, incorporating optical observations, and comparethe calculations with HAWC limits.<br
Searching for TeV Dark Matter in Irregular dwarf galaxies with HAWC Observatory
We present the results of dark matter (DM) searches in a sample of 31 dwarf
irregular (dIrr) galaxies within the field of view of the HAWC Observatory.
dIrr galaxies are DM dominated objects, which astrophysical gamma-ray emission
is estimated to be negligible with respect to the secondary gamma-ray flux
expected by annihilation or decay of Weakly Interacting Massive Particles
(WIMPs). While we do not see any statistically significant DM signal in dIrr
galaxies, we present the exclusion limits () for annihilation
cross-section and decay lifetime for WIMP candidates with masses between
and . Exclusion limits from dIrr galaxies are relevant and
complementary to benchmark dwarf Spheroidal (dSph) galaxies. In fact, dIrr
galaxies are targets kinematically different from benchmark dSph, preserving
the footprints of different evolution histories. We compare the limits from
dIrr galaxies to those from ultrafaint and classical dSph galaxies previously
observed with HAWC. We find that the contraints are comparable to the limits
from classical dSph galaxies and orders of magnitude weaker than
the ultrafaint dSph limits.Comment: 22 pages, 11 figures, 3 table
The High-Altitude Water Cherenkov (HAWC) Observatory in M\'exico: The Primary Detector
The High-Altitude Water Cherenkov (HAWC) observatory is a second-generation
continuously operated, wide field-of-view, TeV gamma-ray observatory. The HAWC
observatory and its analysis techniques build on experience of the Milagro
experiment in using ground-based water Cherenkov detectors for gamma-ray
astronomy. HAWC is located on the Sierra Negra volcano in M\'exico at an
elevation of 4100 meters above sea level. The completed HAWC observatory
principal detector (HAWC) consists of 300 closely spaced water Cherenkov
detectors, each equipped with four photomultiplier tubes to provide timing and
charge information to reconstruct the extensive air shower energy and arrival
direction. The HAWC observatory has been optimized to observe transient and
steady emission from sources of gamma rays within an energy range from several
hundred GeV to several hundred TeV. However, most of the air showers detected
are initiated by cosmic rays, allowing studies of cosmic rays also to be
performed. This paper describes the characteristics of the HAWC main array and
its hardware.Comment: Accepted for publications in Nuclear Inst. and Methods in Physics
Research, A (2023) 168253 (
https://www.sciencedirect.com/science/article/abs/pii/S0168900223002437 ); 39
pages, 14 Figure
Probing invisible neutrino decay with KM3NeT-ORCA
In the era of precision measurements of the neutrino oscillation parameters,
upcoming neutrino experiments will also be sensitive to physics beyond the
Standard Model. KM3NeT/ORCA is a neutrino detector optimised for measuring
atmospheric neutrinos from a few GeV to around 100 GeV. In this paper, the
sensitivity of the KM3NeT/ORCA detector to neutrino decay has been explored. A
three-flavour neutrino oscillation scenario, where the third neutrino mass
state decays into an invisible state, e.g. a sterile neutrino, is
considered. We find that KM3NeT/ORCA would be sensitive to invisible neutrino
decays with ~ at confidence
level, assuming true normal ordering. Finally, the impact of neutrino decay on
the precision of KM3NeT/ORCA measurements for ,
and mass ordering have been studied. No significant effect of neutrino decay on
the sensitivity to these measurements has been found.Comment: 27 pages, 14 figures, bibliography updated, typos correcte
Measurement of atmospheric neutrino mixing with improved IceCube DeepCore calibration and data processing
We describe a new data sample of IceCube DeepCore and report on the latest measurement of atmospheric neutrino oscillations obtained with data recorded between 2011â2019. The sample includes significant improvements in data calibration, detector simulation, and data processing, and the analysis benefits from a sophisticated treatment of systematic uncertainties, with significantly greater level of detail since our last study. By measuring the relative fluxes of neutrino flavors as a function of their reconstructed energies and arrival directions we constrain the atmospheric neutrino mixing parameters to be sin2Ξ23=0.51±0.05 and Îm232=2.41±0.07Ă10â3ââeV2, assuming a normal mass ordering. The errors include both statistical and systematic uncertainties. The resulting 40% reduction in the error of both parameters with respect to our previous result makes this the most precise measurement of oscillation parameters using atmospheric neutrinos. Our results are also compatible and complementary to those obtained using neutrino beams from accelerators, which are obtained at lower neutrino energies and are subject to different sources of uncertainties
Observation of high-energy neutrinos from the Galactic plane
The origin of high-energy cosmic rays, atomic nuclei that continuously impact
Earth's atmosphere, has been a mystery for over a century. Due to deflection in
interstellar magnetic fields, cosmic rays from the Milky Way arrive at Earth
from random directions. However, near their sources and during propagation,
cosmic rays interact with matter and produce high-energy neutrinos. We search
for neutrino emission using machine learning techniques applied to ten years of
data from the IceCube Neutrino Observatory. We identify neutrino emission from
the Galactic plane at the 4.5 level of significance, by comparing
diffuse emission models to a background-only hypothesis. The signal is
consistent with modeled diffuse emission from the Galactic plane, but could
also arise from a population of unresolved point sources.Comment: Submitted on May 12th, 2022; Accepted on May 4th, 202
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