arXiv subjects

Juan A. Aguilar

Publications and source records attributed to Juan A. Aguilar.

7 recordsLinked to original sources

arXiv2023

Indirect dark matter search in the Galactic Centre with IceCube

It is assumed that dark matter can annihilate or decay into Standard Model particles which then can produce a neutrino flux detectable at IceCube. Such a signal can be emitted from the Galactic Center thanks to the high density of dark matter abundance being gravitationally captured. This analysis aims at searching for neutrino signals from dark matter annihilation and decay in the Galactic Center using $\sim$9 years of IceCube-DeepCore data with an optimized selection for low energy. In this contribution, we present the sensitivities on the thermally averaged dark matter self-annihilation cross-section for dark matter masses ranging from 5 GeV up to 8 TeV.

astro-ph.HE↗

arXiv2023

Search for dark matter annihilations in the center of the Earth with IceCube

The nature of Dark Matter remains one of the most important unresolved questions of fundamental physics. Many models, including the Weakly Interacting Massive Particles (WIMPs), assume Dark Matter to be a particle and predict a weak coupling with Standard Model matter. If Dark Matter particles can scatter off nuclei in the vicinity of a massive object, such as a star or a planet, they may lose kinetic energy and become gravitationally trapped in the center of such objects, including Earth. As Dark Matter accumulates in the center of the Earth, self-annihilation of WIMPs into Standard Model particles can result in an excess of neutrinos coming from the center of the Earth and detectable at the IceCube Neutrino Observatory, situated at the geographic South Pole. A search for excess neutrinos from these annihilations has been performed on 10 years of IceCube data, and results have been interpreted in the context of a number of WIMP annihilation channels ($χχ\rightarrowτ^+τ^-/W^+W^-/b\bar{b}$) and masses ranging from 10 GeV to 10 TeV. We present the results from this analysis and compare the outcome with previous searches by other experiments. This analysis yields competitive and world-leading results for masses $m_χ$ > 100 GeV.

astro-ph.HE↗

arXiv2021

Indirect search for dark matter in the Galactic Centre with IceCube

Even though there are strong astrophysical and cosmological indications to support the existence of dark matter, its exact nature remains unknown. We expect dark matter to produce standard model particles when annihilating or decaying, assuming that it is composed of Weakly Interacting Massive Particles (WIMPs). These standard model particles could in turn yield neutrinos that can be detected by the IceCube neutrino telescope. The Milky Way is expected to be permeated by a dark matter halo with an increased density towards its centre. This halo is expected to yield the strongest dark matter annihilation signal at Earth coming from any celestial object, making it an ideal target for indirect searches. In this contribution, we present the sensitivities of an indirect search for dark matter in the Galactic Centre using IceCube data. This low energy dark matter search allows us to cover dark matter masses ranging from 5 GeV to 1 TeV. The sensitivities obtained for this analysis show considerable improvements over previous IceCube results in the considered energy range.

astro-ph.HE↗

arXiv2018

In-situ molecular-level observation of methanol catalysis at the water-graphite interface

Methanol occupies a central role in chemical synthesis and is considered an ideal candidate for cleaner fuel storage and transportation. It can be catalyzed from water and volatile organic compounds such as carbon dioxide, thereby offering an attractive solution for reducing carbon emissions. However molecular-level experimental observations of the catalytic process are scarce, and most existing catalysts tend to rely on empirically optimized, expensive and complex nano- composite materials. This lack of molecular-level insights has precluded the development of simpler, more cost-effective alternatives. Here we show that graphite immersed in ultrapure water is able to spontaneously catalyze methanol from volatile organic compounds in ambient conditions. Using single-molecule resolution atomic force microscopy (AFM) in liquid, we directly observe the formation and evolution of methanol-water nanostructures at the surface of graphite. These molecularly ordered structures nucleate near catalytically active surface features such as atomic step edges and grow progressively as further methanol is being catalyzed. Complementary nuclear magnetic resonance analysis of the liquid confirms the formation of methanol and quantifies its concentration. We also show that electric fields significantly enhance the catalysis rate, even when as small as that induced by the natural surface potential of the silicon AFM tip. These findings could have a significant impact on the development of organic catalysts and on the function of nanoscale carbon devices.

physics.chem-ph↗

arXiv2013

Neutrino searches with the IceCube telescope

The IceCube Neutrino Observatory is an array of 5,160 photomultipliers (PMTs) deployed on 86 strings at 1.5-2.5 km depth within the ice at the South Pole. The main goal of the IceCube experiment is the detection of an astrophysical neutrino signal. In this contribution we present the results of the point source analysis on the data taken from April 2008 to May 2011, when three detector configurations were operated: the 40-string configuration (IC-40), the 59-string configuration (IC-59) and the 79-string configuration (IC-79). No significant excess indicative of point sources of neutrinos has been found, and we present upper limits for an $E^{-2}$ muon neutrino flux for a list of candidate sources. For the first time these limits start to reach $10^{-12}$ TeV$^{-1}$ cm$^{-2}$ s$^{-1}$ in some parts of the sky.

astro-ph.HE↗

arXiv2011

Online Gamma-Ray Burst catalog for neutrino telescopes

The origin of cosmic rays is still one of the unresolved questions in modern physics. Violent and high energetic explosions of γ-ray emission known as Gamma Ray Bursts (GRBs) are perhaps one of the main candidates of sources of hadron acceleration and therefore of neutrino emission. Neutrino telescopes search for signatures of cosmic neutrinos such as an excess of neutrinos in time and space coincidence with a GRB. These searches use catalogues of GRBs by satellite experiments. The online catalog presented here is a useful tool that provides a reference catalog of GRBs for neutrino telescopes in particular and GRBs analyzers in general.

astro-ph.IM↗

arXiv2010

Search for neutrino point sources with the IceCube Neutrino Observatory

The IceCube Neutrino Observatory is a kilometer-scale detector currently under construction at the South Pole. The full detector will comprise 5,160 photomultipliers (PMTs) deployed on 86 strings from 1.45-2.45 km deep within the ice. As of the austral summer of 2009-10, 73 out of the total number strings have been deployed, and the detector is reaching its final construction phase. A dense sub-array of 6 strings in the center of the detector (DeepCore) has been already installed for enhancing the sensitivity to low energy neutrinos. The IceCube de- tection principle is based on the measurement of the Cherenkov light induced by ultra-relativistic muons and showers produced by neutrino interactions in the target matter of the detector. The main scientific goal of the IceCube experiment is the detection of astrophysical neu- trinos that will help to understand and settle the unresolved questions about the origin and nature of cosmic rays. In this contribution we will present the latest results of the experiment concerning the search for neutrino point sources using the experimental data taken during 2008- 09 where the detector was operated with a 40-string configuration. The results of the analysis for steady individual neutrino sources as well as the stacking analysis from different catalogs will be presented.

astro-ph.IM↗