Browsing by Subject "Astrofísica"

Now showing items 21-40 of 142

    • 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 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 / National Aeronautics and Space Administration. 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)
      External 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 ...

    • Discovery of Cl-34g,Cl-m(p,gamma)Ar-35 resonances activated at classical nova temperatures 

      Fry, C.; Wrede, Christopher; Bishop, Shawn M.; Brown, B. A.; Chen, Alan A.; Faestermann, Thomas; Hertenberger, R.; Parikh, Anuj Ramesh; Perez Loureiro, D; Wirth, Hans Friedrich; Garcia, A.; Ortez, Ronaldo (2015-01-13)
      Article
      Open Access
      Background: The thermonuclear Cl-34g,Cl-m(p,gamma)Ar-35 reaction rates are unknown due to a lack of experimental nuclear physics data. Uncertainties in these rates translate to uncertainties in S-34 production in models ...

    • Distorsiones de espacio-tiempo y los viajes interestelares 

      Martín Cabezón, Rubén (2009-10-20)
      Audiovisual
      Open Access
      Desde que a principios del siglo XX la Relatividad General hiciera su aparición, nuestra comprensión de la gravedad, una de las fuerzas más primordiales (y poco comprendida), ha aumentado considerablemente. Esta teoría ...

    • Dynamical behavior of asteroids near resonance: the 4:1 gap and the 7:2 group 

      Grau Sánchez, Miguel; González Casado, Guillermo (1999-08)
      Article
      Restricted access - publisher's policy
      A comparative study of the evolution of the Sun–Jupiter–Asteroid system near the 4:1 and 7:2 resonances is performed by means of two techniques that proceed differently from the Hamiltonian corresponding to the planar ...

    • Eccentricity samples: implications on the potential and the velocity distribution 

      Cubarsí Morera, Rafael; Stojanovic, Milan; Ninkovic, Slobodan (2017)
      Article
      Open Access
      Planar and vertical epicycle frequencies and local angular velocity are related to the derivatives up to the second order of the local potential and can be used to test the shape of the potential from stellar disc samples. ...

    • Electron density retrieval from truncated Radio Occultation GNSS data 

      Lyu, Haixia; Hernández Pajares, Manuel; Monte Moreno, Enrique; Cardellach Galí, Estel (2019-06-01)
      Article
      Open Access
      This paper summarizes the definition and validation of two complementary new strategies, to invert incomplete Global Navigation Satellite System Radio-Occultation (RO) ionospheric measurements, such as the ones to be ...

    • Enrico Fermi : de les partícules a l'astrofísica 

      Hernández Fernández, Antonio (2018-12)
      Part of book or chapter of book
      Open Access
      Enrico Fermi (1901-1954) va revolucionar la física del segle XX tot capitanejant el desenvolupament de la física nuclear i de partícules, disciplines que, com veurem, va connectar amb l’astronomia, entre d’altres matèries, ...