61.
Constraints on the physics of type Ia supernovae from the X-ray spectrum of the Tycho supernova remnant
- Badenes, C; Borkowski, K J; Hughes, J P; Hwang, U; Bravo Guil, Eduardo
We explore the relationship between the models for progenitor systems of Type Ia supernovae and the properties of the supernova remnants that evolve after the explosion. Most models for Type Ia progenitors in the single-degenerate scenario predict substantial outflows during the presupernova evolution. Expanding on previous work, we estimate the imprint of these outflows on the structure of the circumstellar medium at the time of the supernova explosion, and the effect that this modified circumstellar medium has on the evolution of the ensuing supernova remnant. We compare our simulations with the observational properties of known Type Ia supernova remnants in...
62.
Are the models for type Ia supernova progenitors consistent with the properties of supernova remnants?
- Badenes, C; Hughes, J P; Bravo Guil, Eduardo; Langer, N
We explore the relationship between the models for progenitor systems of Type Ia supernovae and the properties of the supernova remnants that evolve after the explosion. Most models for Type Ia progenitors in the single-degenerate scenario predict substantial outflows during the presupernova evolution. Expanding on previous work, we estimate the imprint of these outflows on the structure of the circumstellar medium at the time of the supernova explosion, and the effect that this modified circumstellar medium has on the evolution of the ensuing supernova remnant. We compare our simulations with the observational properties of known Type Ia supernova remnants in...
63.
The science of y-ray spectroscopy
- Isern Vilaboy, Jordi; Bravo Guil, Eduardo; Hirschmann, Alina
The explosion mechanism associated with thermonuclear supernovae (SNIa) is still a matter of debate. Nevertheless, there is a wide agreement that high amounts of radioactive nuclei are produced during these events, that are expected to be strong γ-ray emitters. In this paper we investigate the use of γ-rays as a diagnostic tool. For this purpose we have performed a complete study of the γ-ray spectra associated with all the different scenarios currently proposed: detonation, deflagration, delayed detonation, pulsating delayed detonation and off-center detonation. Our study shows that the γ-ray emission from SNIa is, effectively, a promising tool but that must...
64.
P-process nucleosynthesis in detonating white dwarfs in the light of multidimensional hydrodynamical models
- Goriely, S; García Senz, Domingo; Bravo Guil, Eduardo; José Pont, Jordi
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...
65.
A model grid for the spectral analysis of X-ray emission in young Type Ia supernova remnants
- Badenes Montoliu, Carles; Bravo Guil, Eduardo; Borkowski, K.J.
We address a new set of models for the spectral analysis of the X-ray emission from young, ejecta-dominated Type Ia supernova remnants. These models are based on hydrodynamic simulations of the interaction between Type Ia supernova explosion models and the surrounding ambient medium, coupled to self-consistent ionization and electron heating calculations in the shocked supernova ejecta, and the generation of synthetic spectra with an appropriate spectral code. The details are provided elsewhere, but in this paper we concentrate on a specific class of Type Ia explosion models (delayed detonations), commenting on the differences that arise between their synthetic X-ray spectra...
66.
Hypersonic collision of a blast wave on a low-mass star
- García Senz, Domingo; Serichol Augué, Núria; Bravo Guil, Eduardo
When a neutron star is born as a result of the accretion-induced collapse (AIC) of a white dwarf, a small but signi_cant fraction of its mass can be simultaneously expelled at a velocity of around 104 kms −1. In
this paper we study the collision between the gas ejected during the AIC of a white dwarf and a 0.3 M_ mainsequence star by using numerical simulation techniques. We found that, for a plausible combination of the orbital parameters and impact energy, the low-mass star is completely destroyed. This scenario can help to explain the origin of isolated millisecond pulsars.
67.
Type Ia Supernova models arising from different distributions of igniting points
- García Senz, Domingo; Bravo Guil, Eduardo
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.
68.
The science of y-ray spectroscopy
- Isern Vilaboy, Jordi; Bravo Guil, Eduardo; Hirschmann, Alina
The explosion mechanism associated with thermonuclear supernovae (SNIa) is still a matter of debate. Nevertheless, there is a wide agreement that high amounts of radioactive nuclei are produced during these events, that are expected to be strong γ-ray emitters. In this paper we investigate the use of γ-rays as a diagnostic tool. For this purpose we have performed a complete study of the γ-ray spectra associated with all the different scenarios currently proposed: detonation, deflagration, delayed detonation, pulsating delayed detonation and off-center detonation. Our study shows that the γ-ray emission from SNIa is, effectively, a promising tool but that must...
69.
P-process nucleosynthesis in detonating white dwarfs in the light of multidimensional hydrodynamical models
- Goriely, S; García Senz, Domingo; Bravo Guil, Eduardo; José Pont, Jordi
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...
70.
A model grid for the spectral analysis of X-ray emission in young Type Ia supernova remnants
- Badenes, C; Bravo Guil, Eduardo; Borkowski, K J
We address a new set of models for the spectral analysis of the X-ray emission from young, ejecta-dominated Type Ia supernova remnants. These models are based on hydrodynamic simulations of the interaction between Type Ia supernova explosion models and the surrounding ambient medium, coupled to self-consistent ionization and electron heating calculations in the shocked supernova ejecta, and the generation of synthetic spectra with an appropriate spectral code. The details are provided elsewhere, but in this paper we concentrate on a specific class of Type Ia explosion models (delayed detonations), commenting on the differences that arise between their synthetic X-ray spectra...
71.
Hypersonic collision of a blast wave on a low-mass star
- García Senz, Domingo; Serichol Augué, Núria; Bravo Guil, Eduardo
When a neutron star is born as a result of the accretion-induced collapse (AIC) of a white dwarf, a small but signi_cant fraction of its mass can be simultaneously expelled at a velocity of around 104 kms −1. Inthis paper we study the collision between the gas ejected during the AIC of a white dwarf and a 0.3 M_ mainsequence star by using numerical simulation techniques. We found that, for a plausible combination of the orbital parameters and impact energy, the low-mass star is completely destroyed. This scenario can help to explain the origin of isolated millisecond pulsars.
72.
Type Ia Supernova models arising from different distributions of igniting points
- García Senz, Domingo; Bravo Guil, Eduardo
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.
73.
Coulomb corrections to the equation of state of nuclear statistical equilibrium matter: implications for SNIa nucleosynthesis and the accretion-induced collapse of white dwarfs
- Bravo Guil, Eduardo; García Senz, Domingo
Coulomb corrections to the equation of state of degenerate matter are usually neglected in high-temperature regimes, owing to the inverse dependence of the plasma coupling constant, G, on temperature. However, nuclear statistical equilibrium matter is characterized by a large abundance by mass of large-Z (iron group) nuclei. It is found that Coulomb corrections to the ion ideal gas equation of state of matter in nuclear statistical equilibrium are important at temperatures T≲5–10×109 K and densities ρ≳108 g cm−3. At a temperature T=8.5×109 K and a density ρ=8×109 g cm−3, the neutronization rate is larger by ≳28 per cent when Coulomb...
74.
The fate of CO white dwarfs that experience slow deflagrations
- Bravo Guil, Eduardo; Domínguez, I; Isern Vilaboy, Jordi
It has been suggested that the differences among the observational Type Ia supernovae (SNIa) set can be accounted for by invoking two regimes of propagation of combustion. Normal SNIa should be produced by rapid deflagrations that rapidly propagate across a white dwarf, while dim SNIa should be a consequence of a detonation issued during the contraction phase of a pulsation induced by a very slow conductive deflagration. In this paper, we explore the observational consequences of deflagrations, the properties of which are in between both behaviours. Using different laws for the flame velocity as a function of flame radius, a...
75.
Coulomb corrections to the equation of state of nuclear statistical equilibrium matter: implications for SNIa nucleosynthesis and the accretion-induced collapse of white dwarfs
- Bravo Guil, Eduardo; García Senz, Domingo
Coulomb corrections to the equation of state of degenerate matter are usually neglected in high-temperature regimes, owing to the inverse dependence of the plasma coupling constant, G, on temperature. However, nuclear statistical equilibrium matter is characterized by a large abundance by mass of large-Z (iron group) nuclei. It is found that Coulomb corrections to the ion ideal gas equation of state of matter in nuclear statistical equilibrium are important at temperatures T≲5–10×109 K and densities ρ≳108 g cm−3. At a temperature T=8.5×109 K and a density ρ=8×109 g cm−3, the neutronization rate is larger by ≳28 per cent when Coulomb...
76.
The fate of CO white dwarfs that experience slow deflagrations
- Bravo Guil, Eduardo; Domínguez, I; Isern Vilaboy, Jordi
It has been suggested that the differences among the observational Type Ia supernovae (SNIa) set can be accounted for by invoking two regimes of propagation of combustion. Normal SNIa should be produced by rapid deflagrations that rapidly propagate across a white dwarf, while dim SNIa should be a consequence of a detonation issued during the contraction phase of a pulsation induced by a very slow conductive deflagration. In this paper, we explore the observational consequences of deflagrations, the properties of which are in between both behaviours. Using different laws for the flame velocity as a function of flame radius, a...
77.
Production of short-lived radioactive nuclei in Super Asymptotic Giant Branch stars
- Doherty, Carolyn L.; Lugaro, M.; Lau, H. H. B.; Siess, Lionel; Lattanzio, John; Gil Pons, Pilar
78.
Production of short-lived radioactive nuclei in Super Asymptotic Giant Branch stars
- Doherty, Carolyn L.; Lugaro, M.; Lau, H. H. B.; Siess, Lionel; Lattanzio, John; Gil Pons, Pilar
79.
Narcís Monturiol i la seva Idea General del Universo (1874)
- Roca Rosell, Antoni Maria Claret
En els darrers anys de la seva vida, Narcís
Monturiol actuà com a dirigent republicà,
no solament participant en la formació de
noves organitzacions, sinó també en la tasca
de difondre una ideologia progressista.
En la conferència que analitzem en aquest
article, Monturiol oferí la perspectiva de
què es disposava a la seva època sobre la
constitució de l’Univers. Com ell mateix va
dir, es tractava de fer veure que la ciència
era una de les principals eines de transformació
social.
80.
Narcís Monturiol i la seva Idea General del Universo (1874)
- Roca Rosell, Antoni Maria Claret
En els darrers anys de la seva vida, NarcísMonturiol actuà com a dirigent republicà,no solament participant en la formació denoves organitzacions, sinó també en la tascade difondre una ideologia progressista.En la conferència que analitzem en aquestarticle, Monturiol oferí la perspectiva dequè es disposava a la seva època sobre laconstitució de l’Univers. Com ell mateix vadir, es tractava de fer veure que la ciènciaera una de les principals eines de transformaciósocial.
