Browsing by Subject "Astrofísica"

Now showing items 21-40 of 167

    • Assessment of global ionospheric maps performance by means of ionosonde data 

      Jerez, Gabriel Olivera; Hernández Pajares, Manuel; Prol, Fabricio dos Santos; Alves, Daniele Barroca Marra; Monico, João Francisco Galera (Multidisciplinary Digital Publishing Institute (MDPI), 2020-10-21)
      Article
      Open Access
      This work presents a new method for assessing global ionospheric maps (GIM) using ionosonde data. The method is based on the critical frequency at the F2 layer directly measured by ionosondes to validate VTEC (vertical ...

    • Assessment of St. Patrick's Day 2015 Geomagnetic storm impact on EGNOS 

      Hernández Pajares, Manuel; Béniguel, Yannick; Orús Pérez, Raul; Prieto Cerdeira, Roberto; García Rigo, Alberto; Kinrade, J; Kauristie, Kirsti; Schlueter, Stefan; Serant, Damien; Krankowski, Andrzej; Secretan, Hugues; Sampedro Casis, Rodrigo; Prats Menéndez, Xavier (European Space Agency (ESA), 2015)
      Conference lecture
      Restricted access - publisher's policy
      The Monitor project has been designed to monitor ionospheric events that would allow evaluating its impact on European GNSS Systems. It includes a network of ionospheric scintillation monitoring stations in various ...

    • Assessment of the capabilities and applicability of ionospheric perturbation indices provided in Europe 

      Borries, Claudia; Wilken, Volken; Jacobsen, Knut Stanley; García Rigo, Alberto; Dziak-Jankowska, Beata; Kervalishvili, Guram; Jakowski, Norbert; Tsagouri, Ioanna; Hernández Pajares, Manuel; Ferreira, Arthur A.; Hoque, Mainul (2020-08-01)
      Article
      Open Access
      Perturbations in the ionosphere are of great interest not only for scientific research, but also for applications using transionospheric radiosignals (e.g. GNSS applications and HF communication), because the transmission ...

    • Astrophysical parameter determination using chaotic orbital regions 

      Nicolás Álvarez, Jorge (Universitat Politècnica de Catalunya, 2018-02-27)
      Master thesis
      Open Access
      Covenantee:   European Space Research and Technology Centre
      The goal of this thesis is to show that chaotic orbits of a dynamical system are advantageous (compared with regularnes) to determine the characteristic parameters of the system, and to give an estimate about the behaviour ...

    • Axions and the luminosity function of white dwarfs : the thin and thick discs, and the halo 

      Isern Vilaboy, Jordi; García-Berro Montilla, Enrique; Torres Gil, Santiago; Cojocaru, Elena Ruxandra; Catalán, S (Oxford University Press, 2018-08-01)
      Article
      Open Access
      The evolution of white dwarfs is a simple gravothermal process of cooling. Since the shape of their luminosity function is sensitive to the characteristic cooling time, it is possible to use its slope to test the existence ...

    • Beta-decay half-lives and beta-delayed neutron emission probabilities for several isotopes of Au, Hg, Tl, Pb, and Bi, beyond N = 126 

      Caballero-Folch, R.; Domingo-Pardo, C; Agramunt Ros, Jorge; Calviño Tavares, Francisco; Cortés Rossell, Guillem Pere (2017-06-23)
      Article
      Open Access
      Background: There have been measurements on roughly 230 nuclei that are beta-delayed neutron emitters. They range from 8He up to 150La. Apart from 210Tl, with a branching ratio of only 0.007%, no other neutron emitter has ...

    • Beyond the required LISA free-fall performance: new LISA pathfinder results down to 20 mu Hz 

      Armano, M.; Audley, H.; Baird, J.; Binetruy, P.; Ramos Castro, Juan José (American Institute of Physics (AIP), 2018-02-05)
      Article
      Open Access
      In the months since the publication of the first results, the noise performance of LISA Pathfinder has improved because of reduced Brownian noise due to the continued decrease in pressure around the test masses, from a ...

    • Characterisation of the Hamamatsu photomultipliers for the KM3NeT Neutrino Telescope 

      Aiello, S; Ameli, F; André, Michel; Anghinolfi, Marco; Anton, G.; Ardid Ramírez, Miguel; Avgitas, T.; Bertin, V.; Bormuth, R.; Bouwhuis, M.C.; Puricelli, Stefano; Cherubini, Silvio; Coniglione, R.; Mannheim, Karl; Morganti, Michele; Pellegrino, Carlo; Piattelli, P.; Real, Del; Santangelo, A; Sharma, Aniruddh; Trovato, A.; Zaborov, D.; Zúñiga Román, Juan (2018-05-01)
      Article
      Open Access
      The Hamamatsu R12199-02 3-inch photomultiplier tube is the photodetector chosen for the first phase of the KM3NeT neutrino telescope. About 7000 photomultipliers have been characterised for dark count rate, timing spread ...

    • Characteristics and energy dependence of recurrent galactic cosmic-ray flux depressions and of a forbush decrease with LISA Pathfinder 

      Armano, M.; Audley, H.; Baird, J.; Bassan, M.; Benella, S.; Lobo, J.A.; Ramos Castro, Juan José (2018-02-16)
      Article
      Open Access
      Galactic cosmic-ray (GCR) energy spectra observed in the inner heliosphere are modulated by the solar activity, the solar polarity and structures of solar and interplanetary origin. A high counting rate particle detector ...

    • Classical and recurrent nova models 

      José Pont, Jordi; Casanova Bustamante, Jordi; García-Berro Montilla, Enrique; Hernanz Carbó, Margarita; Shore, Steven N.; Calder, A. (2011)
      Conference lecture
      Open Access
      Remarkable progress in the understanding of nova outbursts has been achieved through combined efforts in photometry, spectroscopy and numerical simulations. According to the thermonuclear runaway model, novae are powered ...

    • Coincident observations by the Kharkiv IS radar and ionosonde, DMSP and Arase (ERG) satellites, and FLIP model simulations: implications for the NRLMSISE-00 hydrogen density, plasmasphere, and ionosphere 

      Kotov, Dmytro; Richards, Philip G.; Truhlík, Vladimír; Hernández Pajares, Manuel (2018-08)
      Article
      Open Access
      This paper reports the results of ionosphere and plasmasphere observations with the Kharkiv incoherent scatter radar and ionosonde, Defense Meteorological Satellite Program, and Arase (ERG) satellites and simulations with ...

    • Comments on: confirming geomagnetic Sfe by means of a solar flare detector based on GNSS 

      Hernández Pajares, Manuel; García Rigo, Alberto (2020-01-01)
      Article
      Open Access
      We report two comments affecting the paper “Curto JJ, Juan JM & Timoté CC, 2019. Confirming geomagnetic Sfe by means of a solar flare detector based on GNSS. J Space Weather Space Clim 9: A42. https://doi.org/10.1051/sws ...

    • Commissioning of the BRIKEN beta-delayed neutron detector for the study of exotic neutron-rich nuclei 

      Tolosa-Delgado, Alvaro; Agramunt Ros, Jorge; Calviño Tavares, Francisco; Cortés Rossell, Guillem Pere; Tarifeño Saldivia, Ariel Esteban (EDP Sciences, 2018)
      Conference lecture
      Open Access
      Beta-delayed neutron emission (Beta-n) is a form of radioactive decay in which an electron, an anti-neutrino and one or more neutrons are emitted. This process arises if the energy window of the decay Q_Beta is greater ...

    • Comparative testing of four ionospheric models driven with GPS measurements 

      Zandbergen, R.; Feltens, Joachim; Angling, M; Jackson Booth, N; Jakowski, Norbert; Hoque, Mainul; Hernández Pajares, Manuel; Aragón Ángel, María Ángeles; Orús Pérez, Raül (2011-07-28)
      Article
      Open Access
      In the context of the European Space Agency/European Space Operations Centre funded Study “GNSS Contribution to Next Generation Global Ionospheric Monitoring,” four ionospheric models based on GNSS data (the Electron ...

    • Constraining the contribution of gamma-ray bursts to the high-energy diffuse neutrino flux with 10 yr of ANTARES data 

      Albert, A.; André, Michel; Anghinolfi, Marco; Anton, Gisela; Ardid Ramírez, Miguel; Aubert, J.-J.; Aublin, J.; Baret, Bruny; Basa, S. (Oxford University Press, 2021-02-01)
      Article
      Open Access
      Addressing the origin of the astrophysical neutrino flux observed by IceCube is of paramount importance. Gamma-Ray Bursts (GRBs) are among the few astrophysical sources capable of achieving the required energy to contribute ...

    • Constraining the origin of the short timescales X-ray variability of the Seyfert galaxy NGC 7469 

      Núñez Arilla, Carlos (Universitat Politècnica de Catalunya, 2020-06)
      Bachelor thesis
      Open Access
      Covenantee:   Nicolaus Copernicus Astronomical Center
      This bachelor thesis is a small part of a much larger project related to the study of the X-ray properties of the active galactic nucleus (AGN) NGC 7469. In this report I will focus on the analysis of the short-timescales ...

    • Constraints on the neutrino emission from the Galactic Ridge with the ANTARES telescope 

      Anghinolfi, Marco; Anton, G.; André, Michel; Avgitas, T.; Bertin, V.; Bormuth, R.; Puricelli, Stefano; Coniglione, R.; Gleixner, A; Lefèvre, Dominique; Michael, Turner; Pellegrino, Carlo; Piattelli, P.; Sanchez Losa, Agustín; Schnabel, J. (Elsevier, 2016-09-10)
      Article
      Open Access
      A highly significant excess of high-energy astrophysical neutrinos has been reported by the IceCube Collaboration. Some features of the energy and declination distributions of IceCube events hint at a North/South asymmetry ...

    • Control system of the balloon experimental twin telescope for infrared interferometry 

      Casalprim Torres, Marc (Universitat Politècnica de Catalunya, 2017-09)
      Master thesis
      Open Access
      Covenantee:   Institut Supérieur de l'Aéronautique et de l'Espace / Goddard Space Flight Center
      The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is a far infrared telescope on a balloon-based platform that will validate the interferometry technique for future space telescopes. It is one ...

    • Data gathering and methodology 

      Sanz Subirana, Jaume; Juan Zornoza, José Miguel (2018-10-31)
      Research report
      Open Access
      The aim of this WP5 is to specify the impact of TID in EGNOS, N-RTK and HF systems through statistical correlation of the performance data recorded from system operators and of TID detection results. The analysis will be ...

    • Deep model simulation of polar vortices in gas giant atmospheres 

      García González, Fernando; Chambers, Frank; Watts, Anna (Oxford University Press, 2020-11-04)
      Article
      Open Access
      The Cassini and Juno probes have revealed large coherent cyclonic vortices in the polar regions of Saturn and Jupiter, a dramatic contrast from the east–west banded jet structure seen at lower latitudes. Debate has centred ...