Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 50 of 111 results
  • Access to the full text
    Observation of SN2011fe with INTEGRAL - I : pre-maximum phase  Open access

     Isern Vilaboy, Jordi; Jean, Pierre; Bravo Guil, Eduardo; Diehl, Roland; Knödlseder, Jurgen; Domingo, A.; Hirschmann, Alina; Hoeflich, Peter; Lebrun, F.; Renaud, M; Soldi, Simona; Elias-Rosa, Nancy; Hernanz Carbó, Margarita; Kulebi, Baybar; Zhang, X.; Badenes, C.; Domínguez Aguilera, Inmaculada; Garcia Senz, Domingo; Jordi, Carme; Lichti, G.; Vedrenne, G.; von Ballmoos, Peter
    Astronomy and astrophysics
    Date of publication: 2013-04
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Context. SN2011fe was detected by the Palomar Transient Factory in M101 on August 24, 2011, a few hours after the explosion. From the early optical spectra it was immediately realized that it was a Type Ia supernova, thus making this event the brightest one discovered in the past twenty years. Aims. The distance of the event offered the rare opportunity of performing a detailed observation with the instruments onboard INTEGRAL to detect the ¿-ray emission expected from the decay chains of 56Ni. The observations were performed in two runs, one before and around the optical maximum, aimed to detect the early emission from the decay of 56Ni, and another after this maximum aimed to detect the emission of 56Co. Methods. The observations performed with the instruments onboard INTEGRAL (SPI, IBIS/ISGRI, JEMX, and OMC) were analyzed and compared with the existing models of ¿-ray emission from this kind of supernova. In this paper, the analysis of the ¿-ray emission has been restricted to the first epoch. Results. SPI and IBIS/ISGRI only provide upper limits to the expected emission due to the decay of 56Ni. These upper limits on the gamma-ray flux are 7.1 × 10-5 ph/s/cm2 for the 158 keV line and 2.3 × 10-4 ph/s/cm2 for the 812 keV line. These bounds allow rejecting at the 2s level explosions involving a massive white dwarf, ~1 M¿ in the sub-Chandrasekhar scenario and specifically all models that would have substantial amounts of radioactive 56Ni in the outer layers of the exploding star responsible for the SN2011fe event. The optical light curve obtained with the OMC camera also suggests that SN2011fe was the outcome of the explosion of a CO white dwarf, possibly through the delayed detonation mode, although other ones are possible, of a CO that synthesized ~0.55 M¿ of 56Ni. For this specific model, INTEGRAL would have only been able to detect this early ¿-ray emission if the supernova had occurred at a distance ¿2 Mpc. Conclusions. The detection of the early ¿-ray emission of 56Ni is difficult, and it can only be achieved with INTEGRAL if the distance of the event is close enough. The exact distance depends on the specific SNIa subtype. The broadness and rapid rise of the lines are probably at the origin of this difficulty.

    Context. SN2011fe was detected by the Palomar Transient Factory in M101 on August 24, 2011, a few hours after the explosion. From the early optical spectra it was immediately realized that it was a Type Ia supernova, thus making this event the brightest one discovered in the past twenty years. Aims. The distance of the event offered the rare opportunity of performing a detailed observation with the instruments onboard INTEGRAL to detect the ¿-ray emission expected from the decay chains of 56Ni. The observations were performed in two runs, one before and around the optical maximum, aimed to detect the early emission from the decay of 56Ni, and another after this maximum aimed to detect the emission of 56Co. Methods. The observations performed with the instruments onboard INTEGRAL (SPI, IBIS/ISGRI, JEMX, and OMC) were analyzed and compared with the existing models of ¿-ray emission from this kind of supernova. In this paper, the analysis of the ¿-ray emission has been restricted to the first epoch. Results. SPI and IBIS/ISGRI only provide upper limits to the expected emission due to the decay of 56Ni. These upper limits on the gamma-ray flux are 7.1 × 10-5 ph/s/cm2 for the 158 keV line and 2.3 × 10-4 ph/s/cm2 for the 812 keV line. These bounds allow rejecting at the 2s level explosions involving a massive white dwarf, ~1 M¿ in the sub-Chandrasekhar scenario and specifically all models that would have substantial amounts of radioactive 56Ni in the outer layers of the exploding star responsible for the SN2011fe event. The optical light curve obtained with the OMC camera also suggests that SN2011fe was the outcome of the explosion of a CO white dwarf, possibly through the delayed detonation mode, although other ones are possible, of a CO that synthesized ~0.55 M¿ of 56Ni. For this specific model, INTEGRAL would have only been able to detect this early ¿-ray emission if the supernova had occurred at a distance ¿2 Mpc. Conclusions. The detection of the early ¿-ray emission of 56Ni is difficult, and it can only be achieved with INTEGRAL if the distance of the event is close enough. The exact distance depends on the specific SNIa subtype. The broadness and rapid rise of the lines are probably at the origin of this difficulty.

  • High resolution-simulations of the head-on collisions of white dwarfs

     Garcia Senz, Domingo; Cabezon Gomez, Ruben Martin; Arcones, Almudena; Relaño, Antonio; Thielemann, Friedrich-K
    Monthly notices of the Royal Astronomical Society
    Date of publication: 2013-11-10
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Smoothed particle hydrodynamics: checking a tensor approach to calculating gradients  Open access

     Escartín, José Antonio; Garcia Senz, Domingo; Cabezón, Rubén Martin
    Scientific Meeting of the Spanish Astronomical Society
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    We describe and check a novel formulation of Smoothed Particle Hydrodynamics (SPH) based on an Integral Approach to the Derivatives, called IAD0, that can be applied to simulate astrophysical systems. The method relies in a tensor approach to calculating gradients, which is more accurate than the standard procedure (STD), due to its better renormalization properties. The proposed scheme fully conserves momentum and energy in isentropic ows, and is less susceptible to the pairing instability. The resulting algorithm is veried using two tests: a two-dimensional simulation of the Kelvin-Helmholtz instability and the three-dimensional simulation of the merging of two polytropes. The analysis of these test cases suggests that the method is able to improve the results of the standard technique with only a moderate computational overload.

  • Access to the full text
    Testing the concept of integral approach to derivatives within the smoothed particle hydrodynamics technique in astrophysical scenarios  Open access

     Cabezón Gómez, Rubén Martín; Garcia Senz, Domingo; Escartin Vigo, Jose Antonio
    Astronomy and astrophysics
    Date of publication: 2012
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Context. The smoothed particle hydrodynamics (SPH) technique is a well-known numerical method that has been applied to simulating the evolution of a wide variety of systems. Modern astrophysical applications of the method rely on the Lagrangian formulation of fluid Euler equations, which is fully conservative. A different scheme, based on a matrix approach to the SPH equations is currently being used in computational fluid dynamics. An original matrix formulation of SPH based on an integral approach to the derivatives, called IAD0, has been recently proposed and is fully conservative and well-suited to simulating astrophysical processes. Aims. The behavior of the IAD0 scheme is analyzed in connection with several astrophysical scenarios, and compared to the same simulations carried out with the standard SPH technique. Methods. The proposed hydrodynamic scheme is validated using a variety of numerical tests that cover important topics in astrophysics, such as the evolution of supernova remnants, the stability of self-gravitating bodies, and the coalescence of compact objects. Results. The analysis of the hydrodynamical simulations of the above-mentioned astrophysical scenarios suggests that the SPH scheme built with the integral approach to the derivatives improves the results of the standard SPH technique. In particular, there is a better development of hydrodynamic instabilities, a good description of self-gravitating structures in equilibrium and a reasonable description of the process of coalescence of two white dwarfs. We also observed good conservations of energy and both linear and angular momenta that were generally better than those of standard SPH. In addition the new scheme is less susceptible to pairing instability. Conclusions. We present a formalism based on a tensor approach to Euler SPH equations that we checked using a variety of three-dimensional tests of astrophysical interest. This new scheme is more accurate because of the re-normalization imposed on the interpolations, which is fully conservative and less prone to undergoing the pairing instability. The analysis of these test cases suggests that the method may improve the simulation of many astrophysical problems with only a moderate computational overload.

  • Is there a hidden hole in type Ia supernova remnants?

     Garcia Senz, Domingo; Badenes, Carles; Serichol, N.
    Astrophysical journal
    Date of publication: 2012-01-20
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Improving smoothed particle hydrodynamics with an integral approach to calculating gradients  Open access

     Garcia Senz, Domingo; Cabezón Gómez, Rubén Martín; Escartin Vigo, Jose Antonio
    Astronomy and astrophysics
    Date of publication: 2012-01-26
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Context. The smoothed particle hydrodynamics (SPH) technique is a well-known numerical method that has been applied to simulate the evolution of a wide variety of systems. Modern astrophysical applications of the method rely on the Lagrangian formulation of fluid Euler equations, which is fully conservative. A different scheme, based on a matrix approach to the SPH equations is currently being used in computational fluid dynamics. These matrix formulations achieve better interpolations of the physical magnitudes but they are, in general, not fully conservative. The matrix approach to the Euler equations has never been used in astrophysics. Aims. We develop and test a fully conservative SPH scheme based on a tensor formulation that can be applied to simulate astrophysical systems. Methods. In the proposed scheme, derivatives are calculated from an integral expression that leads to a tensor (instead of a vectorial) estimation of gradients and reduces to the standard formulation in the continuum limit. The new formulation improves the interpolation of physical magnitudes, leading to a set of conservative equations that resembles those of standard SPH. The resulting scheme is verified using a variety of well-known tests, all of them simulated in two dimensions. We also discuss an application of the proposed tensor method to astrophysics by simulating the stability of a Sun-like polytrope calculated in three dimensions. Results. The proposed scheme is able to improve the results of standard SPH in the two-dimensional tests, especially in the simulation of subsonic hydrodynamic instabilities. Our results for the stability of the Sun-like polytrope suggest that the new method can be used in astrophysics to carry out three-dimensional calculations with a computational cost that is only slightly higher (i.e. ≤50% for a serial code) than that of a standard SPH formulation. Conclusions. A formalism based on a matrix approach to Euler SPH equations was developed and checked. The new scheme is more accurate because of the re-normalization imposed on the interpolations, which is fully conservative and probably less prone to undergo the tensile instability. The analysis of several test cases suggest that the method may improve the simulation of both subsonic and supersonic systems. An application of the tensor method to astrophysics is, for the first time, successfully carried out. These encouraging results indicates that more work should be invested in the applications of matrix SPH formulations to astrophysics.

  • AxisSPH:Devising and validating an axisymmetric smoothed particle hydrodynamics code  Open access

     Relaño Castillo, Antonio
    Defense's date: 2012-06-06
    Department of Physics and Nuclear Engineering, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    A two-dimensional axisymmetric implementation of the smoothed particle hydrodynamics (SPH) technique, called for short AxisSPH, has been described in this thesis, along with a number of basic tests and realistic applications. The main goal of this work was to fill a gap on a topic which has been scarcely addressed in the published literature concerning SPH. Although the application of AxisSPH to the simulation of real problems is restricted to those systems which display the appropriate symmetry there are, however, many interesting examples of physical systems which evolve following the axisymmetric premise. These examples belong to a variety of scientific and technological areas such as, for example, astrophysics, laboratory astrophysics or inertial confinement fusion. Additionally AxisSPH can be also useful in convergence studies of the standard 3D-SPH technique because the higher resolution achieved in 2D can be used to benchmark the three-dimensional codes. The main improvements implemented in AxisSPH with respect existing axisymmetric SPH formulations are summarized as follows: 1) We have derived simple analytical expressions for correction factors which largely improves the calculation of density and velocity in the vicinity of the z-axis. These expressions and their derivatives were given as a function of an adimensional parameter and do not increase the computational load of the scheme. 2) We have obtained the appropriate expression of the fluid Euler equations containing the new correction functions and their derivatives. Far enough from the singular axis, the scheme reduces to the standard formulation discussed by Brookshaw (2003). 3) A novel expression for the heat conduction term, which has to be added to the energy equation was devised and checked. This new term improves the description of the heat flux for those particles located at the axis neighborhoods. 4) Until now axisymmetric SPH hydrocodes handle artificial viscosity using a crude approach because it was treated as a simple restriction of the standard 3D Cartesian viscosity to 2D. Here we propose to calculate the viscous pressure as a combination of two terms, the first one is the (standard) Cartesian part and the second is the axis-converging part of the viscosity respectively. As expected this last term is of special relevance to simulate implosions. 5) We have developed an original method to incorporate gravity into AxisSPH. First the direct ring to ring force was found as a function of the Euclidean distance between the 2D particles. In second place the gravitational force on a given particle was obtained by summing the contributions of all N particles. We have also developed a more efficient scheme to obtain the gravitational force calculating the potential of the ring, instead the force because it involves lesser algebraic operations. The scheme has been checked using a large number of tests cases. These tests range from very specific oriented to check a particular algorithm or a piece of physics, to rather complex ones intended to analyze the behavior of the scheme in potential real applications (ICF, jets, astrophysics). At least in one case, the head on collision of a pair of white dwarfs, the result of the simulations carried out using AxisSPH brings new, unpublished, scientific material.

    En esta tesis se ha desarrollado un código, que hemos llamado AxisSPH, en dos dimensiones axisimétrico a partir de la técnica conocida como SPH (“smooothed particle hydrodynamics”). AxisSPH ha sido validado después de realizar una serie de tests básicos y algunas simulaciones de situaciones reales. El objetivo principal de este trabajo ha sido llenar, en parte, el vacío existente al respecto en la literatura sobre SPH. Aunque sólo se puede aplicar AxisSPH en problemas reales que presenten la apropiada simetría, existen muchos ejemplos interesantes de sistemas físicos que presentan la simetría axial demandada. Existen ejemplos en campos de aplicación tanto científica como tecnológica, por ejemplo en astrofísica, en el llamado laboratorio de astrofísica o en fusión por confinamiento inercial (ICF). Otra interesante aplicación de AxisSPH puede ser su utilización en estudios de convergencia con otros códigos 3D-SPH debido a su mayor resolución, al tratarse de un código 2D. Las mejoras implementadas en el código AxisSPH en comparación con otros códigos axisimétricos SPH existentes se pueden resumir en los siguientes puntos: 1) Hemos deducido expresiones analíticas simples para unos factores de corrección que mejoran el cálculo de la densidad y la velocidad en las proximidades del eje z. Dichas expresiones y sus derivadas dependen de un parámetro adimensional que no incrementa mucho el peso computacional del esquema propuesto. 2) Hemos obtenido las expresiones adecuadas de las ecuaciones de Euler que contienen estas nuevas funciones correctoras y sus derivadas. Lejos del eje de singularidad estas ecuaciones se transforman en las de la formulación estándar propuesta por Brookshaw (2003). 3) Una expresión novedosa del término de conducción, que debe de añadirse a la ecuación de la energía, se ha propuesto y validado. Este nuevo término mejora la evolución del flujo de calor de las partículas situadas en las proximidades del eje z. 4) Hasta el momento los códigos hidrodinámicos SPH axisimétricos existentes trabajaban con una aproximación poco elaborada de la viscosidad artificial ya que consistían en una restricción a dos dimensiones de la viscosidad estándar 3D. En este trabajo proponemos el cálculo de la presión debida a la viscosidad como combinación de dos términos, el primero reflejo de la parte cartesiana y la segunda da cuenta de la parte relacionada con la convergencia en el eje. Como era de esperar este último término es de relevante importancia en la simulación de implosiones. 5) Hemos desarrollado un método original para incorporar el cálculo de la gravedad en el código AxisSPH. En primer lugar la fuerza directa de anillo a anillo y en segundo lugar la fuerza de la gravedad que sufre una determinada partícula a partir de la contribución del resto de las N partículas existentes. También hemos desarrollado un esquema más eficiente para calcular la gravedad a partir del cálculo del potencial del anillo en lugar del cálculo directo de la fuerza ya que implica un menor número de operaciones algebraicas. El método ha sido verificado con un gran número de test numéricos. Desde los más específicos orientados a comprobar la validez de un algoritmo particular o la capacidad para simular un fenómeno físico en particular, hasta simulaciones bastante más complejas, con la intención de validar la capacidad de simular aplicaciones potencialmente más reales (ICF, jets, astrofísica). Así, en al menos un caso, en la colisión frontal de dos enanas blancas, los resultados de la simulación utilizando AxisSPH pueden aportar material científico publicable.

  • Enanas blancas: progenitores, evolución, pulsaciones y explosiones

     Diaz Aguiló, Marc; Renedo Rouco, Isabel; Sala Cladellas, Gloria; Escartin Vigo, Jose Antonio; Loren Aguilar, Pablo; Garcia Senz, Domingo; Torres Gil, Santiago; Camacho Díaz, Judit; Garcia-berro Montilla, Enrique
    Participation in a competitive project

     Share

  • ISFAA, prospects for an implicit Smoothed Particle Hydrodynamics

     Escartín, José Antonio; Garcia Senz, Domingo
    Scientific Meeting of the Spanish Astronomical Society
    Presentation's date: 2012-07-12
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Últimos estadios de la evolución estelar en sistemas binarios: novas clásicas y recurrentes, supernovas, erupciones de rayos X ....

     Bravo Guil, Eduardo; Longland, Richard Leigh; Parikh, Anuj Ramesh; Garcia Senz, Domingo; José Pont, Jordi
    Participation in a competitive project

     Share

  • ISFAA, prospects for an implicit SPH

     Escartín Viu, Antonio; Garcia Senz, Domingo; Cabezón Gómez, Rubén Martín
    International Spheric Workshop
    Presentation's date: 2011-06-09
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Merging in the common envelope and the origin of early R-type stars

     Piersanti, Luciano; Cabezón Gómez, Rubén Martín; Zamora, O.; Dominguez, I.; Garcia Senz, Domingo; Abia, Carlos; Straniero, Oscar
    Astronomy and astrophysics
    Date of publication: 2010-11-04
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    The elusive nature of the r-stars  Open access

     Domínguez, I.; Piersanti, L.; Cabezón Gómez, Rubén Martín; Zamora, O.; Garcia Senz, Domingo; Abia, C.; Straniero, O.
    Memorie della Societá Astronomica Italiana
    Date of publication: 2010-10-10
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    R stars are carbon stars, less luminous and hotter than the carbon stars evolving along the AGB phase. Thus, their carbon enrichment cannot be a consequence of the third dredge-up, a fact also in agreement with the lack of s-element enhancements in their envelopes. Since their discovery the absence of binaries has lead to the conclusion that a previous merger might play a fundamental role in the observed chemical composition, likely through non-standard mixing at the time of the He-flash. On the other hand numerical simulations, in which the He-flash is artificially located close to the edge of a degenerate He core, have successfully induced mixing of carbon into the envelope. In this context it has been suggested that the merger of a degenerate He core with that of a normal red giant star could lead to the formation of a rapidly rotating core undergoing o -centre He ignition in highly degenerate conditions. This scenario is also supported by statistical analysis of the potential mergers that could explain the number, and location in the Galaxy, of observed R stars. Basing on detailed stellar models we will show the evolution of these mergers, that are very common in nature, and do not seem to be the progenitors of (hot) R stars.

  • Physics of Compact Objects: explosive nucleosynthesis and evolution

     José Pont, Jordi; Camacho Díaz, Judit; Torres Gil, Santiago; Renedo Rouco, Isabel; Garcia Senz, Domingo; Sala Cladellas, Gloria; Casanova Bustamante, Jordi; Garcia-berro Montilla, Enrique
    Participation in a competitive project

     Share

  • Physics of compact objects: I.Theorical modeling and observations of stellar explosions

     Casanova Bustamante, Jordi; Loren Aguilar, Pablo; Camacho Díaz, Judit; Sala Cladellas, Gloria; Renedo Rouco, Isabel; Garcia-berro Montilla, Enrique; Garcia Senz, Domingo; Bravo Guil, Eduardo; Torres Gil, Santiago; Longland, Richard Leigh; Parikh, Anuj Ramesh; José Pont, Jordi
    Participation in a competitive project

     Share

  • Hydrodynamical simulations of DNS systems: gravitational emission and equation of state

     Cabezón Gómez, Rubén Martín
    Defense's date: 2010-04-21
    Department of Physics and Nuclear Engineering, Universitat Politècnica de Catalunya
    Theses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Computer simulations using implicit Lagrangian hydrodynamics in 3D  Open access

     Escartin Vigo, Jose Antonio; Garcia Senz, Domingo; Bravo Guil, Eduardo
    Reunion de la Sociedad Española de Astronomia
    Presentation's date: 2010-09-14
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The method known as Smoothed Particle Hydrodynamics (SPH) is an important tool in modern numerical Astrophysics. It has been extensively used to simulate a large number of systems ranging from planets to clusters of galaxies. Nevertheless current applications of the method are restricted to dynamical situations because of the limitations in the time-step imposed by the Courant condition. Here we describe the main features of a new implicit SPH code which is able to handle with several thousand particles and, therefore, it can be used to simulate slowly evolving systems.

  • Pulsating reverse detonation models of Type Ia supernovae. I. Detonation ignition

     Bravo Guil, Eduardo; Garcia Senz, Domingo
    Astrophysical journal
    Date of publication: 2009-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf (WD). Although several scenarios have been proposed and explored by means of one, two, and three-dimensional simulations, the key point still is the understanding of the conditions under which a stable detonation can form in a destabilized WD. One of the possibilities that have been invoked is that an inefficient deflagration leads to the pulsation of a Chandrasekhar-mass WD, followed by formation of an accretion shock around a carbon-oxygen rich core. The accretion shock confines the core and transforms kinetic energy from the collapsing halo into thermal energy of the core, until an inward moving detonation is formed. This chain of events has been termed Pulsating Reverse Detonation (PRD). In this work we explore the robustness of the detonation ignition for different PRD models characterized by the amount of mass burned during the deflagration phase, Mdefl. The evolution of the WD up to the formation of the accretion shock has been followed with a three-dimensional hydrodynamical code with nuclear reactions turned off. We found that detonation conditions are achieved for a wide range of Mdefl. However, if the nuclear energy released during the deflagration phase is close to the WD binding energy (~0.46 × 1051 erg ¿ Mdefl ~ 0.30 M¿) the accretion shock cannot heat and confine the core efficiently and detonation conditions are not robustly achieved.

  • Access to the full text
    Axisymmetric smoothed particle hydrodynamics with self-gravity  Open access

     Garcia Senz, Domingo; Relano, A; Cabezón Gómez, Rubén Martín; Bravo Guil, Eduardo
    Monthly notices of the Royal Astronomical Society
    Date of publication: 2009-01
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The axisymmetric form of the hydrodynamic equations within the smoothed particle hydrodynamics (SPH) formalism is presented and checked using idealized scenarios taken from astrophysics (free fall collapse, implosion and further pulsation of a Sun-like star), gas dynamics (wall heating problem, collision of two streams of gas) and inertial confinement fusion (ablative implosion of a small capsule). New material concerning the standard SPH formalism is given. That includes the numerical handling of those mass points which move close to the singularity axis, more accurate expressions for the artificial viscosity and the heat conduction term and an easy way to incorporate self-gravity in the simulations. The algorithm developed to compute gravity does not rely in any sort of grid, leading to a numerical scheme totally compatible with the Lagrangian nature of the SPH equations.

    The axisymmetric form of the hydrodynamic equations within the smoothed particle hydrodynamics (SPH) formalism is presented and checked using idealized scenarios taken from astrophysics (free fall collapse, implosion and further pulsation of a Sun-like star), gas dynamics (wall heating problem, collision of two streams of gas) and inertial confinement fusion (ablative implosion of a small capsule). New material concerning the standard SPH formalism is given. That includes the numerical handling of those mass points which move close to the singularity axis, more accurate expressions for the artificial viscosity and the heat conduction term and an easy way to incorporate self-gravity in the simulations. The algorithm developed to compute gravity does not rely in any sort of grid, leading to a numerical scheme totally compatible with the Lagrangian nature of the SPH equations.

  • Pulsating reverse detonation models of Type Ia supernovae. II. Explosion

     Bravo Guil, Eduardo; Garcia Senz, Domingo; Cabezón Gómez, Rubén Martín; Domínguez, I
    Astrophysical journal
    Date of publication: 2009-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf (WD). However, all attempts to ¿nd a convincing ignition mechanism based on a delayed detonation in a destabilized, expanding, white dwarf have been elusive so far. One of the possibilities that has been invoked is that an inef¿cient de¿agration leads to pulsation of a Chandrasekhar-mass WD, followed by formation of an accretion shock that con¿nes a carbon¿oxygen rich core, while transforming the kinetic energy of the collapsing halo into thermal energy of the core, until an inward moving detonation is formed. This chain of events has been termed Pulsating Reverse Detonation (PRD). In this work, we present three-dimensional numerical simulations of PRD models from the time of detonation initiation up to homologous expansion. Different models characterized by the amount of mass burned during the de¿agration phase, Mde¿, give explosions spanning a range of kinetic energies, K ~ (1.0¿1.2)×1051 erg, and 56Ni masses, M(56Ni) ~ 0.6¿0.8 M , which are compatible with what is expected for typical Type Ia supernovae. Spectra and light curves of angle-averaged spherically symmetric versions of the PRD models are discussed. Type Ia supernova spectra pose the most stringent requirements on PRD models.

    Observational evidences point to a common explosion mechanism of Type Ia supernovae based on a delayed detonation of a white dwarf (WD). However, all attempts to find a convincing ignition mechanism based on a delayed detonation in a destabilized, expanding, white dwarf have been elusive so far. One of the possibilities that has been invoked is that an inefficient deflagration leads to pulsation of a Chandrasekhar-mass WD, followed by formation of an accretion shock that confines a carbon–oxygen rich core, while transforming the kinetic energy of the collapsing halo into thermal energy of the core, until an inward moving detonation is formed. This chain of events has been termed Pulsating Reverse Detonation (PRD). In this work, we present three-dimensional numerical simulations of PRD models from the time of detonation initiation up to homologous expansion. Different models characterized by the amount of mass burned during the deflagration phase, Mdefl, give explosions spanning a range of kinetic energies, K ∼ (1.0–1.2)×1051 erg, and 56Ni masses, M(56Ni) ∼ 0.6–0.8 M , which are compatible with what is expected for typical Type Ia supernovae. Spectra and light curves of angle-averaged spherically symmetric versions of the PRD models are discussed. Type Ia supernova spectra pose the most stringent requirements on PRD models.

  • DOS RETOS PARA LA EVOLUCION ESTELAR MODERNA:PROGENITORES DE SUPERNOVA Y ESTRELLAS AGB

     Casanova Bustamante, Jordi; Cabezón Gómez, Rubén Martín; Garcia Senz, Domingo; Renedo Rouco, Isabel; Torres Gil, Santiago; Loren Aguilar, Pablo; Camacho Díaz, Judit; Sala Cladellas, Gloria; Escartin Vigo, Jose Antonio; González Villafranca, Alberto; Garcia-berro Montilla, Enrique
    Participation in a competitive project

     Share

  • GRUP D'ASTRONOMIA I ASTROFÍSICA

     Torres Gil, Santiago; Renedo Rouco, Isabel; González Villafranca, Alberto; Cabezón Gómez, Rubén Martín; Garcia Senz, Domingo; Bravo Guil, Eduardo; Diaz Aguiló, Marc; José Pont, Jordi; Riera Mora, M. Angeles; Loren Aguilar, Pablo; Camacho Díaz, Judit; Sala Cladellas, Gloria; Escartin Vigo, Jose Antonio; Casanova Bustamante, Jordi; Garcia-berro Montilla, Enrique
    Participation in a competitive project

     Share

  • Detailed spectral modeling of a three-dimensional pulsating reverse detonation model: too much nickel

     Baron, E.; Jeffery, D J; Branch, D; Bravo Guil, Eduardo; Garcia Senz, Domingo; Hauschildt, P H
    Astrophysical journal
    Date of publication: 2008-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We calculate detailed non-LTE synthetic spectra of a pulsating reverse detonation (PRD) model, a novel explosion mechanism for Type Ia supernovae. While the hydro models are calculated in three dimensions, the spectra use an angle-averaged hydro model and thus some of the three-dimensional (3D) details are lost, but the overall average should be a good representation of the average observed spectra. We study the model at three epochs: maximum light, 7 days prior to maximum light, and 5 days after maximum light. At maximum the defining Si II feature is prominent, but there is also a prominent C II feature, not usually observed in normal SNe Ia near maximum. We compare to the early spectrum of SN 2006D, which did show a prominent C II feature, but the fit to the observations is not compelling. Finally, we compare to the postmaximum UV+optical spectrum of SN 1992A. With the broad spectral coverage it is clear that the iron-peak elements on the outside of the model push too much flux to the red and thus the particular PRD realizations studied would be intrinsically far redder than observed SNe Ia. We briefly discuss variations that could improve future PRD models.

    We calculate detailed non-LTE synthetic spectra of a pulsating reverse detonation (PRD) model, a novel explosion mechanism for Type Ia supernovae. While the hydro models are calculated in three dimensions, the spectra use an angle-averaged hydro model and thus some of the three-dimensional (3D) details are lost, but the overall average should be a good representation of the average observed spectra. We study the model at three epochs: maximum light, 7 days prior to maximum light, and 5 days after maximum light. At maximum the defining Si II feature is prominent, but there is also a prominent C II feature, not usually observed in normal SNe Ia near maximum. We compare to the early spectrum of SN 2006D, which did show a prominent C II feature, but the fit to the observations is not compelling. Finally, we compare to the postmaximum UV+optical spectrum of SN 1992A. With the broad spectral coverage it is clear that the iron-peak elements on the outside of the model push too much flux to the red and thus the particular PRD realizations studied would be intrinsically far redder than observed SNe Ia. We briefly discuss variations that could improve future PRD models.

  • Access to the full text
    A three-dimensional picture of the delayed-detonation model of type Ia supernovae  Open access

     Bravo Guil, Eduardo; Garcia Senz, Domingo
    Astronomy and astrophysics
    Date of publication: 2008-02
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Deflagration models poorly explain the observed diversity of SNIa. Current multidimensional simulations of SNIa predict a significant amount of, so far unobserved, carbon and oxygen moving at low velocities. It has been proposed that these drawbacks can be resolved if there is a sudden jump to a detonation (delayed detonation), but these kinds of models have been explored mainly in one dimension. Here we present new three-dimensional delayed detonation models in which the deflagraton-to-detonation transition (DDT) takes place in conditions like those favored by one-dimensional models. Methods. We have used a smoothed-particle-hydrodynamics code adapted to follow all the dynamical phases of the explosion, with algorithms devised to handle subsonic as well as supersonic combustion fronts. The starting point was a centrally ignited C¿O white dwarf of 1.38 M. When the average density on the flame surface reached ~2-3 × 107 g cm-3 a detonation was launched. Results. The detonation wave processed more than 0.3 M of carbon and oxygen, emptying the central regions of the ejecta of unburned fuel and raising its kinetic energy close to the fiducial 1051 erg expected from a healthy type Ia supernova. The final amount of 56Ni synthesized also was in the correct range. However, the mass of carbon and oxygen ejected is still too high. Conclusions. The three-dimensional delayed detonation models explored here show an improvement over pure deflagration models, but they still fail to coincide with basic observational constraints. However, there are many aspects of the model that are still poorly known (geometry of flame ignition, mechanism of DDT, properties of detonation waves traversing a mixture of fuel and ashes). Therefore, it will be worth pursuing its exploration to see if a good SNIa model based on the three-dimensional delayed detonation scenario can be obtained.

    Aims. Deflagration models poorly explain the observed diversity of SNIa. Current multidimensional simulations of SNIa predict a significant amount of, so far unobserved, carbon and oxygen moving at low velocities. It has been proposed that these drawbacks can be resolved if there is a sudden jump to a detonation (delayed detonation), but these kinds of models have been explored mainly in one dimension. Here we present new three-dimensional delayed detonation models in which the deflagraton-to-detonation transition (DDT) takes place in conditions like those favored by one-dimensional models. Methods. We have used a smoothed-particle-hydrodynamics code adapted to follow all the dynamical phases of the explosion, with algorithms devised to handle subsonic as well as supersonic combustion fronts. The starting point was a centrally ignited C–O white dwarf of 1.38 M . When the average density on the flame surface reached ∼2−3 × 107 g cm−3 a detonation was launched. Results. The detonation wave processed more than 0.3 M of carbon and oxygen, emptying the central regions of the ejecta of unburned fuel and raising its kinetic energy close to the fiducial 1051 erg expected from a healthy type Ia supernova. The final amount of 56Ni synthesized also was in the correct range. However, the mass of carbon and oxygen ejected is still too high. Conclusions. The three-dimensional delayed detonation models explored here show an improvement over pure deflagration models, but they still fail to coincide with basic observational constraints. However, there are many aspects of the model that are still poorly known (geometry of flame ignition, mechanism of DDT, properties of detonation waves traversing a mixture of fuel and ashes). Therefore, it will be worth pursuing its exploration to see if a good SNIa model based on the three-dimensional delayed detonation scenario can be obtained.

  • A one-parameter family of interpolating kernels for Smoothed Particle Hydrodynamics studies

     Cabezón Gómez, Rubén Martín; Garcia Senz, Domingo; Relaño, A
    Journal of computational physics
    Date of publication: 2008-10
    Journal article

     Share Reference managers Reference managers Open in new window

  • Numerical modeling of Type Ia supernovae explosions

     Garcia Senz, Domingo; Bravo Guil, Eduardo
    Reunion de la Sociedad Española de Astronomia
    Presentation's date: 2008-07-08
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • A displayer of stellar hydrodynamics processes

     Escartin Vigo, Jose Antonio; Garcia Senz, Domingo
    Reunion de la Sociedad Española de Astronomia
    Presentation's date: 2008-07-09
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Constraining deflagration models of type Ia supernovae through intermediate-mass elements

     Garcia Senz, Domingo; Bravo Guil, Eduardo; Cabezón Gómez, Rubén Martín; Woosley, S E
    Astrophysical journal
    Date of publication: 2007-05
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The physical structure of a nuclear flame is a basic ingredient of the theory of Type Ia supernovae (SNe Ia). Assuming an exponential density reduction with several characteristic times, we have followed the evolution of a planar nuclear flame in an expanding background from an initial density of 6.6 × 107 g cm-3 down to 2 × 106 g cm-3. The total amount of synthesized intermediate-mass elements (IMEs), from silicon to calcium, was monitored during the calculation. We have used the computed mass fractions, XIME, of these elements to estimate the total amount of IMEs synthesized during the deflagration of a massive white dwarf. Using XIME and adopting the usual hypothesis that the relevant flame speed is actually the turbulent speed on the integral length scale, we have built a simple geometrical approach to model the region where IMEs are thought to be produced. It turns out that a healthy production of IMEs involves the combination of not-too-short expansion times, tc = 0.2 s, and high turbulent intensities. According to our results, it could be difficult to produce much more than 0.2 M¿ of intermediate-mass elements within the standard deflagrative paradigm. The calculations also suggest that the mass of the IMEs scales with the mass of the Fe-peak elements, making it difficult to reconcile energetic explosions with low ejected nickel masses, as in the well-observed supernova SN 1991bg or in SN 1998de. Thus, a large production of Si-peak elements, especially in combination with a low or moderate production of iron, could be better addressed either by the delayed detonation route in standard Chandrasekhar-mass models or, perhaps, by the off-center helium detonation in the sub-Chandrasekhar-mass scenario.

    The physical structure of a nuclear flame is a basic ingredient of the theory of Type Ia supernovae (SNe Ia). Assuming an exponential density reduction with several characteristic times, we have followed the evolution of a planar nuclear flame in an expanding background from an initial density of 6.6 × 107 g cm-3 down to 2 × 106 g cm-3. The total amount of synthesized intermediate-mass elements (IMEs), from silicon to calcium, was monitored during the calculation. We have used the computed mass fractions, XIME, of these elements to estimate the total amount of IMEs synthesized during the deflagration of a massive white dwarf. Using XIME and adopting the usual hypothesis that the relevant flame speed is actually the turbulent speed on the integral length scale, we have built a simple geometrical approach to model the region where IMEs are thought to be produced. It turns out that a healthy production of IMEs involves the combination of not-too-short expansion times, τc ≥ 0.2 s, and high turbulent intensities. According to our results, it could be difficult to produce much more than 0.2 M☉ of intermediate-mass elements within the standard deflagrative paradigm. The calculations also suggest that the mass of the IMEs scales with the mass of the Fe-peak elements, making it difficult to reconcile energetic explosions with low ejected nickel masses, as in the well-observed supernova SN 1991bg or in SN 1998de. Thus, a large production of Si-peak elements, especially in combination with a low or moderate production of iron, could be better addressed either by the delayed detonation route in standard Chandrasekhar-mass models or, perhaps, by the off-center helium detonation in the sub-Chandrasekhar-mass scenario.

  • SAI+6 ORDINADORS

     Garcia Senz, Domingo
    Participation in a competitive project

     Share

  • Simulations of radiative shocks and jet formation in laboratory plasmas

     Velarde, Pedro; González, Matthias; Oliva, Eduardo; Kasperczuk, Andrzej; Pisarczyk, Tadeusz; Ullschmied, Jiri; Stehlé, Chantal; Rus, Bedrich; Garcia Senz, Domingo; Bravo Guil, Eduardo; Relaño, Antonio
    5th International conference on inertial fusion sciences and applications : September 9-14, 2007 : Kobe, Japan
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We present the simulations of two relevant hydrodynamical problems related to astrophysical phenomena performed by three different codes. The numerical results from these codes will be compared in order to test both the numerical method implemented inside them and the influence of the physical phenomena simulated by the codes. Under some conditions laser produced plasmas could be scaled to the typical conditions prevailing in astrophysical plasmas. Therefore, such similarity allows to use existing laser facilities and numerical codes suitable to a laser plasma regime, for studying astrophysical proccesses. The codes are the radiation fluid dynamic 2D ARWEN code and the 3D HERACLES, and, without radiation energy transport, a Smoothed-Particle Hydrodynamics (SPH) code. These codes use diferent numerical techniques and have overlapping range of application, from laser produced plasmas to astrophysical plasmas. We also present the first laser experiments obtaining cumulative jets with a velocity higher than 100 km/s.

    We present the simulations of two relevant hydrodynamical problems related to astrophysical phenomena performed by three different codes. The numerical results from these codes will be compared in order to test both the numerical method implemented inside them and the influence of the physical phenomena simulated by the codes. Under some conditions laser produced plasmas could be scaled to the typical conditions prevailing in astrophysical plasmas. Therefore, such similarity allows to use existing laser facilities and numerical codes suitable to a laser plasma regime, for studying astrophysical proccesses. The codes are the radiation fluid dynamic 2D ARWEN code and the 3D HERACLES, and, without radiation energy transport, a Smoothed-Particle Hydrodynamics (SPH) code. These codes use diferent numerical techniques and have overlapping range of application, from laser produced plasmas to astrophysical plasmas. We also present the first laser experiments obtaining cumulative jets with a velocity higher than 100 km/s.

  • The merging of white dwarf and neutron star systems: gravitational radiation

     Garcia Senz, Domingo; Garcia-berro Montilla, Enrique; Pedemonte, A G; Loren-Aguilar, P; Isern Vilaboy, Jordi; Lobo, J A
    Journal of physics: conference series
    Date of publication: 2007-09
    Journal article

     Share Reference managers Reference managers Open in new window

  • Interaction of supernovae remnants: from the circumstellar medium to the terrestrial laboratory

     Velarde, P; Garcia Senz, Domingo; Bravo Guil, Eduardo; Ogando, Francisco; Relaño, A; González, E; Lachaise, M; Oliva, E
    Journal de physique IV
    Date of publication: 2006-06
    Journal article

     Share Reference managers Reference managers Open in new window

  • Beyond the bubble catastrophe of type Ia supernovae: pulsating reverse detonation models

     Bravo Guil, Eduardo; Garcia Senz, Domingo
    The astrophysical journal letters
    Date of publication: 2006-05
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We describe a mechanism by which a failed deflagration of a Chandrasekhar-mass carbon-oxygen white dwarf can turn into a successful thermonuclear supernova explosion, without invoking an ad hoc high-density deflagration-detonation transition. Following a pulsating phase, an accretion shock develops above a core of 1 M_sun composed of carbon and oxygen, inducing a converging detonation. A three-dimensional simulation of the explosion produced a kinetic energy of 1.05E51 ergs and 0.70 M_sun of 56Ni, ejecting scarcely 0.01 M_sun of C-O moving at low velocities. The mechanism works under quite general conditions and is flexible enough to account for the diversity of normal Type Ia supernovae. In given conditions the detonation might not occur, which would reflect in peculiar signatures in the gamma and UV-wavelengths.

  • Access to the full text
    Interaction of Supernovae remnants: from the circumstellar medium to the terrestrial laboratory  Open access

     Velarde, P; Garcia Senz, Domingo; Bravo Guil, Eduardo; Ogando, Francisco; Relaño, A; Oliva, E
    Physics of plasmas
    Date of publication: 2006-09
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The evolution of supernova remnants (SNRs) represents a useful and natural laboratory for gasdynamics studies. In this paper the results of several hydrodynamical simulations of the propagation and early phases of interaction of two SNRs embedded in a homogeneous interstellar environment are shown. In particular, the hydrodynamic evolution and collision of twin SNRs during their self-similar stage has been simulated using a two-dimensional Lagrangian hydrocode. In addition, the results of a detailed simulation that attempts to set the adequate conditions to reproduce the same phenomenon through laser ablation of two plastic plugs at the laboratory scale are presented. These results indicate that both large-scale and small-scale simulations display several common features that can be used to design an experiment aimed to validate the hydrodynamical codes. Of particular interest are the structures found around the juncture of the two colliding shells produced by the interaction of the remnants.

    The evolution of supernova remnants (SNRs) represents a useful and natural laboratory for gasdynamics studies. In this paper the results of several hydrodynamical simulations of the propagation and early phases of interaction of two SNRs embedded in a homogeneous interstellar environment are shown. In particular, the hydrodynamic evolution and collision of twin SNRs during their self-similar stage has been simulated using a two-dimensional Lagrangian hydrocode. In addition, the results of a detailed simulation that attempts to set the adequate conditions to reproduce the same phenomenon through laser ablation of two plastic plugs at the laboratory scale are presented. These results indicate that both large-scale and small-scale simulations display several common features that can be used to design an experiment aimed to validate the hydrodynamical codes. Of particular interest are the structures found around the juncture of the two colliding shells produced by the interaction of the remnants.

  • The Late stages of stellar evolution : stellar explosions and non-interacting white dwarfs in the UV

     Hernanz Carbó, Margarita; Dominguez, I.; Garcia-berro Montilla, Enrique; Garcia Senz, Domingo; Barstow, M.A.; Bravo Guil, Eduardo; Gonzalez-Riestra, R.; Isern, J.; José Pont, Jordi; Torres Gil, Santiago
    Date of publication: 2006-12
    Book chapter

     Share Reference managers Reference managers Open in new window

  • The stagnation phase of an ICF capsule simulated with an axisymmetrical smoothed-particle hydrodynamics code

     Garcia Senz, Domingo
    29th European Conference on Laser Interaction with Matter
    Presentation's date: 2006-05-12
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Single point off-center helium ignitions as origin of some type la supernovae

     Garcia Senz, Domingo
    International Symposium on Nuclear Astrophysics - Nuclei in de Cosmos IX
    Presentation's date: 2006-06-28
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • The merging of white dwarf and neutron star systems: gravitational radiation

     Garcia Senz, Domingo; Garcia-berro Montilla, Enrique; Gutierrez Pedemonte, Alba; Lorén-Aguilar, Pablo; Jordi, Isern; José, A Lobo
    XXIXth Spanish Relativity Meeting
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Interaction between the ejected mass in supernovae explosions with different types of secondary stars

     Serichol Augue, Nuria; Garcia Senz, Domingo
    Highlights of Spanish Astrophysics IV
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Single point off-center helium ignitions as origin of some Type Ia supernovae

     Forcada Garcia, Ramon; Garcia Senz, Domingo; José Pont, Jordi
    International Symposium on Nuclear Astrophysics - Nuclei in de Cosmos IX
    Presentation's date: 2006
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • The Stagnation phase of an ICF capsule simulated with an axisymmetrical smoothed particle hydrodynamics code

     Relaño, A; Garcia Senz, Domingo; Bravo Guil, Eduardo
    29th European Conference on Laser Interaction with Matter
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • The late stages of stellar evolution: stellar explosions and non-interacting white dwarfs in the UV

     Hernanz Carbó, Margarita; Domínguez, Inmaculada; Garcia-berro Montilla, Enrique; Garcia Senz, Domingo; Barstow, M. A.; Bravo Guil, Eduardo; González Riestra, R.; Isern Vilaboy, Jorge; José Pont, Jordi; Torres, S
    The World Space Observatory Ultraviolet (WSO/UV) project-Spain 2003-2005
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Type Ia Supernova models arising from different distributions of igniting points  Open access

     Garcia Senz, Domingo; Bravo Guil, Eduardo
    Astronomy and astrophysics
    Date of publication: 2005-02
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    In this paper we address the theory of type Ia supernovae from the moment of carbon runaway up to several hours after the explosion. We have concentrated on the boiling-pot model: a deflagration characterized by the (nearly-) simultaneous ignition of a number of bubbles that pervade the core of the white dwarf.

    In this paper we address the theory of type Ia supernovae from the moment of carbon runaway up to several hours after the explosion. We have concentrated on the boiling-pot model: a deflagration characterized by the (nearly-) simultaneous ignition of a number of bubbles that pervade the core of the white dwarf.

  • Access to the full text
    P-process nucleosynthesis in detonating white dwarfs in the light of multidimensional hydrodynamical models  Open access

     Goriely, S; Garcia Senz, Domingo; Bravo Guil, Eduardo; José Pont, Jordi
    Astronomy and astrophysics
    Date of publication: 2005-12
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The p-process nucleosynthesis in He-accreting white dwarfs with sub-Chandrasekhar mass is revisited in the light of multi-dimensional hydrodynamical simulations. Post-processing calculations are performed on a sample of well-chosen track particles representative of the core and envelope material that is subject to the p-process. The p-abundance distributions in the disrupted core as well as in the ejected envelope are estimated and compared with previous analysis based on spherical-symmetric simulations. The present calculations confirm the results obtained in 1D simulations and the possibility to produce in particular the puzzling Mo and Ru p-isotopes in the envelope, provided it is initially enriched in s-process elements.

    The p-process nucleosynthesis in He-accreting white dwarfs with sub-Chandrasekhar mass is revisited in the light of multi-dimensional hydrodynamical simulations. Post-processing calculations are performed on a sample of well-chosen track particles representative of the core and envelope material that is subject to the p-process. The p-abundance distributions in the disrupted core as well as in the ejected envelope are estimated and compared with previous analysis based on spherical-symmetric simulations. The present calculations confirm the results obtained in 1D simulations and the possibility to produce in particular the puzzling Mo and Ru p-isotopes in the envelope, provided it is initially enriched in s-process elements.

  • Multidimensional Type Ia Supernovae models

     Garcia Senz, Domingo
    First CARINA workshop: Perspectives in European Nuclear Astrophysics
    Presentation's date: 2005-06-08
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • INTERACCIÓ DEL MATERIAL EXPULSAT EN LES EXPLOSIONS DE SUPERNOVA AMB DIFERENTS TIPUS D'ESTELS ACOMPANYANTS

     Serichol Augue, Nuria
    Defense's date: 2005-06-21
    Department of Physics and Nuclear Engineering, Universitat Politècnica de Catalunya
    Theses

     Share Reference managers Reference managers Open in new window

  • Gamma-ray emission from type Ia supernovae

     Isern Vilaboy, Jordi; Bravo Guil, Eduardo; Hirschmann, A; Garcia Senz, Domingo
    New astronomy reviews
    Date of publication: 2004-02
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The explosion mechanism associated with thermonuclear supernovae is still a matter of debate. Since huge amounts of radioactive elements are synthesized during such explosions, it is possible to use the associated ¿-ray emission as a diagnostic tool. In this paper we show, however, that for some values of the parameters that characterize the burning front propagation, the signatures overlap, thus avoiding a clear distinction among them. We also display some preliminary results obtained from 3-D simulations showing the influence of inhomogeneities in the ¿-ray spectrum.

    The explosion mechanism associated with thermonuclear supernovae is still a matter of debate. Since huge amounts of radioactive elements are synthesized during such explosions, it is possible to use the associated γ-ray emission as a diagnostic tool. In this paper we show, however, that for some values of the parameters that characterize the burning front propagation, the signatures overlap, thus avoiding a clear distinction among them. We also display some preliminary results obtained from 3-D simulations showing the influence of inhomogeneities in the γ-ray spectrum.

  • High-temperature combustion : approaching equilibrium using nuclear networks

     Cabezón Gómez, Rubén Martín; Garcia Senz, Domingo; Bravo Guil, Eduardo
    Astrophysical journal supplement series
    Date of publication: 2004-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    A method for integrating the chemical equations associated with nuclear combustion at high temperature is presented and extensively checked. Following the idea of Mu¨ller, the feedback between nuclear rates and temperature was taken into account by simultaneously computing molar fraction changes and temperature response in the same matrix. The resulting algorithm is very stable and ef¿cient at calculating nuclear combustion in explosive scenarios, especially in those situations where the reacting material manages to climb to the nuclear statistical equilibrium regime. The numerical scheme may be useful not only for those who carry out hydrodynamical simulations of explosive events, but also as a tool to investigate the properties of a nuclear System approaching equilibrium through a variety of thermodynamical trajectories.

  • Thermonuclear supernova models, and observations of Type Ia supernovae

     Bravo Guil, Eduardo; Badenes Montoliu, Carles; Garcia Senz, Domingo
    International Astrophysical Conference. Interacting Binaries: Accretion, Evolution and Outcomes
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Hydrodynamic Simulation of Neutron Star Mergers

     Garcia Senz, Domingo
    JENAM 2004 The Many Scales in the Universe
    Presentation's date: 2004-09-14
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window