839 research outputs found
Gravitational Waves From Known Pulsars: Results From The Initial Detector Era
We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom
Horizontal muon track identification with neural networks in HAWC
Nowadays the implementation of artificial neural networks in high-energyphysics has obtained excellent results on improving signal detection. In thiswork we propose to use neural networks (NNs) for event discrimination in HAWC.This observatory is a water Cherenkov gamma-ray detector that in recent yearshas implemented algorithms to identify horizontal muon tracks. However, thesealgorithms are not very efficient. In this work we describe the implementationof three NNs: two based on image classification and one based on objectdetection. Using these algorithms we obtain an increase in the number ofidentified tracks. The results of this study could be used in the future toimprove the performance of the Earth-skimming technique for the indirectmeasurement of neutrinos with HAWC.<br
A Contribution of the HAWC Observatory to the TeV era in the High Energy Gamma-Ray Astrophysics: The case of the TeV-Halos
We present a short overview of the TeV-Halos objects as a discovery and a
relevant contribution of the High Altitude Water \v{C}erenkov (HAWC)
observatory to TeV astrophysics. We discuss history, discovery, knowledge, and
the next step through a new and more detailed analysis than the original study
in 2017. TeV-Halos will contribute to resolving the problem of the local
positron excess observed on the Earth. To clarify the latter, understanding the
diffusion process is mandatory.Comment: Work presented in the 21st International Symposium on Very High
Energy Cosmic Ray Interactions(ISVHECRI 2022) as part of the Ph. D. Thesis of
Ramiro Torres-Escobedo (SJTU, Shanghai, China). Accepted for publication in
SciPost Physics Proceedings (ISSN 2666-4003). 11 pages, 3 Figures. Short
overview of HAWC and TeV Halos objects until 202
Fatores associados ao início da vida sexual de adolescentes matriculados em uma unidade de saúde da família da zona leste do Município de São Paulo, Brasil
Global data on earthworm abundance, biomass, diversity and corresponding environmental properties
14 p.Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change
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
Medios de comunicación y derecho a la información en Jalisco, 2016
Se rescata el acontecer mediático y las trasformaciones más relevantes en materia de derecho a la información entre 2015 y 2016. Este periodo arroja interesantes análisis con respecto a temas como los cambios del sistema de medios en Jalisco; la trasparencia y el acceso a la información, así como la configuración de quienes integran las instituciones que vigilan su aplicación; la transición a la televisión digital terrestre; los desaparecidos y la falta de acceso a la información, y el rostro de la prensa local a partir de sus capacidades financieras desde la perspectiva de su independencia editorial. Asimismo, se registraron hechos importantes que están marcando un parteaguas en el estado, como la alerta de violencia contra las mujeres en Jalisco, la iniciativa ciudadana #Ley3de3, las modificaciones al Premio Jalisco de Periodismo y las implicaciones del nuevo sistema penal para los medios y los periodistas. Cierra con un espacio para mantener viva la memoria de los profesionales de la comunicación que han participado en la construcción del acontecer informativo, cultural y de entretenimiento local
Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914" (2016, ApJL, 826, L13)
This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands
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Global data on earthworm abundance, biomass, diversity and corresponding environmental properties
Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change
Methods and results of a search for gravitational waves associated with gamma-ray bursts using the GEO 600, LIGO, and Virgo detectors
Paper producido por "The LIGO Scientific Collaboration and the Virgo Collaboration". (En el registro se mencionan solo algunos autores de las decenas de personas que participan).In this paper we report on a search for short-duration gravitational wave bursts in the frequency range 64 Hz–1792 Hz associated with gamma-ray bursts (GRBs), using data from GEO 600 and one of the LIGO or Virgo detectors. We introduce the method of a linear search grid to analyze GRB events with large sky localization uncertainties, for example the localizations provided by the Fermi Gamma-ray Burst Monitor (GBM). Coherent searches for gravitational waves (GWs) can be computationally intensive when the GRB sky position is not well localized, due to the corrections required for the difference in arrival time between
detectors. Using a linear search grid we are able to reduce the computational cost of the analysis by a factor of Oð10Þfor GBM events. Furthermore, we demonstrate that our analysis pipeline can improve upon the sky localization of GRBs detected by the GBM, if a high-frequency GW signal is observed in coincidence. We use the method of the linear grid in a search for GWs associated with 129 GRBs observed satellite-based gamma-ray experiments between 2006 and 2011. The GRBs in our sample had not been previously analyzed for GW counterparts. A fraction of our GRB events are analyzed using data from GEO 600 while
the detector was using squeezed-light states to improve its sensitivity; this is the first search for GWs using data from a squeezed-light interferometric observatory. We find no evidence for GW signals, either with any individual GRB in this sample or with the population as a whole. For each GRB we place lower bounds on the distance to the progenitor, under an assumption of a fixed GWemission energy of 10−2M⊙c2, with a median exclusion distance of 0.8 Mpc for emission at 500 Hz and 0.3 Mpc at 1 kHz. The reduced computational cost associated with a linear search grid will enable rapid searches for GWs associated with
Fermi GBM events once the advanced LIGO and Virgo detectors begin operation.http://journals.aps.org/prd/abstract/10.1103/PhysRevD.89.122004publishedVersionFil: Aasi, J. LIGO. California Institute of Technology; Estados Unidos de América.Fil: Domínguez, E. Argentinian Gravitational Wave Group; Argentina.Fil: Maglione, C. Argentinian Gravitational Wave Group; Argentina.Fil: Reula, O. Argentinian Gravitational Wave Group; Argentina.Fil: Ortega, W. Argentinian Gravitational Wave Group; Argentina.Fil: Wolovick, N. Argentinian Gravitational Wave Group; Argentina.Fil: Schilman, M. Argentinian Gravitational Wave Group; Argentina.Física de Partículas y Campo
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