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Papers by Domingo García-Senz
Astrophysics and Space Science, 2001
SIXE (Spanish Italian X-ray Experiment) is an X-ray detector withgeometric area of 2300 cm2, form... more SIXE (Spanish Italian X-ray Experiment) is an X-ray detector withgeometric area of 2300 cm2, formed by four identical gas-filledMulticell Proportional Counters, and devoted to study the long termspectroscopy of selected X-ray sources in the energy range 3–50 keV. Themain characteristics of SIXE are: time accuracy of 1 microsecond,spectral resolution of 5% for E > 35 keV and 46/vE% for E
Cosmic Chemical Evolution, 2002
Astronomy and Astrophysics
A currently favored model for Type Ia supernovae consists of a carbon-oxygen (CO) white dwarf ( ~... more A currently favored model for Type Ia supernovae consists of a carbon-oxygen (CO) white dwarf ( ~ 0.6-1.0 M_sun), surrounded by a thick layer of helium ( ~ 0.2-0.3 M_sun), which explodes as a consequence of successive detonations in the helium layer and the CO core. Previous studies, carried out in one and two dimensions, have shown that this model is capable of providing light curves and late-time spectra in agreement with observations, though the peak light spectrum may be problematic. These same studies also highlighted a key uncertainty in the model. When properly considered in three dimensions, will the helium detonation actually succeed in igniting a corresponding detonation in the carbon core? In this paper we follow the hydrodynamic evolution of a representative case calculated in three dimensions using the smoothed particle (SPH) approach to multi-dimensional hydrodynamical modeling. Several fine zoned simulations are also carried out in one dimension to elucidate shock hyd...
The Astrophysical Journal, 1995
The Astrophysical Journal, 2012
In this paper we report on the bulk features of the hole carved by the companion star in the mate... more In this paper we report on the bulk features of the hole carved by the companion star in the material ejected during a Type Ia supernova explosion. In particular we are interested in the long term evolution of the hole as well as in its fingerprint in the geometry of the supernova remnant after several centuries of evolution, which is a hot topic in current Type Ia supernovae studies. We use an axisymmetric smoothed particle hydrodynamics code to characterize the geometric properties of the supernova remnant resulting from the interaction of this ejected material with the ambient medium. Our aim is to use supernova remnant observations to constrain the single degenerate scenario for Type Ia supernova progenitors. Our simulations show that the hole will remain open during centuries, although its partial or total closure at later times due to hydrodynamic instabilities is not excluded. Close to the edge of the hole, the Rayleigh-Taylor instability grows faster, leading to plumes that approach the edge of the forward shock. We also discuss other geometrical properties of the simulations, like the evolution of the contact discontinuity. Subject headings: supernova: general, supernova remnants spread the combustion to the whole mass of the star in a time scale of the order of a second, triggering a thermonuclear explosion. Hydrodynamic models of this kind of explosion suggest that the observed nucleosynthetic yields and kinetic energies are better explained if the deflagration turns into a detonation (i.e. supersonic burning) at some point, Höeflich & Khokhlov (1996), Gamezo, Khokhlov & Oran (2005), but a consensus theoretical model -4for Type Ia supernovae does not exist yet.
Nuclear Physics A, 2003
We present a straightforward integration method to compute the abundance and temperature evolutio... more We present a straightforward integration method to compute the abundance and temperature evolution in explosive scenarios. In this approach the thermal equation is implicitely coupled with chemical equations in order to avoid instabilities and ensure a gentle transition from the normal combustion regime to the quasi (QSE) and complete nuclear statistical equilibrium (NSE). Two nuclear networks, with 14 nuclei (α-network) and 86 nuclei (including protons and neutrons) respectively, have been considered. The scheme is suitable to cope with a variety of explosive burning regimes.
Supernovae: lights in the darkness, 2007
The signal of neutron star (NS) mergers has the imprint of the EOS of dense nuclear matter, which... more The signal of neutron star (NS) mergers has the imprint of the EOS of dense nuclear matter, which is still not well known. A set of gravitational waves (GW) signals have been calculated from 3D hydrodynamical simulations of NS-NS mergers using the Smoothed Particle Hydrodynamics technique (SPH) with different EOS. By analyzing the morphology and time evolution of the signal we want to be able to discriminate among the variety of proposed EOS after a successful GW detection has been done.
AIP Conference Proceedings, 1994
ESO ASTROPHYSICS SYMPOSIA, 2003
We present several hydrodynamical simulations of thermonuclear supernovae dealing with multiple d... more We present several hydrodynamical simulations of thermonuclear supernovae dealing with multiple delayed detonations. The calculations were carried out in three dimensions, making possible to study the influence of geometry of the flame front in two aspects. First, the evolution of its fractal dimension during the deflagration phase has been followed until a critical value is reached such that the deflagration may turn into a detonation. Second, as the resulting detonation could probably be scattered through the flame, the effect of its initial location on the detonation propagation, final energetics and nucleosynthesis has been explored.
We describe and check a novel formulation of Smoothed Particle Hydrodynamics (SPH) based on an In... more We describe and check a novel formulation of Smoothed Particle Hydrodynamics (SPH) based on an Integral Approach to the Derivatives, called IAD_0, 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 flows, and is less susceptible to the pairing instability. The resulting algorithm is verified 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.
Lecture Notes in Physics, 1989
ABSTRACT
Astronomy & Astrophysics, 2014
Context. The smoothed particle hydrodynamics (SPH) technique is a numerical method for solving ga... more Context. The smoothed particle hydrodynamics (SPH) technique is a numerical method for solving gas-dynamical problems that has been applied to simulate the evolution of a wide variety of astrophysical systems. The method has a second-order accuracy, with a resolution that is usually much larger in the compressed regions than in the diluted zones of the fluid. Aims. We propose and check a method to balance and equalize the resolution of SPH between high and low density regions. This method relies in the versatility of a family of interpolators called sinc kernels, which allows to increase the quality of interpolations just varying a single parameter (the exponent of the sinc function). Methods. The proposal is checked and validated through a number of numerical tests, going from standard onedimensional Riemann problems in shock tubes, to multidimensional simulations of explosions, hydrodynamic instabilities and the collapse of a sun-like polytrope.
Thermonuclear Supernovae, 1997
The Astrophysical Journal, 1995
Some results of a set of tridimensional calculations concerning the explosion of a white dwarf by... more Some results of a set of tridimensional calculations concerning the explosion of a white dwarf by means of a smooth particle hydrodynamics (SPH) code are presented. The burning front advance is solved along with the hydrodynamics of the whole star, and a characterization of the front surface in terms of fractal concepts is done. Our main result indicates that the surface of the deflagration front sought at the largest scales of the Rayleigh-Taylor instability can be characterized as a fractal with a time-dependent dimension, D(t), whose value is 2 Յ D(t) Յ 2.4.
Astrophysics and Space Science Library, 1997
Astrophysics and Space Science, 2001
SIXE (Spanish Italian X-ray Experiment) is an X-ray detector withgeometric area of 2300 cm2, form... more SIXE (Spanish Italian X-ray Experiment) is an X-ray detector withgeometric area of 2300 cm2, formed by four identical gas-filledMulticell Proportional Counters, and devoted to study the long termspectroscopy of selected X-ray sources in the energy range 3–50 keV. Themain characteristics of SIXE are: time accuracy of 1 microsecond,spectral resolution of 5% for E > 35 keV and 46/vE% for E
Cosmic Chemical Evolution, 2002
Astronomy and Astrophysics
A currently favored model for Type Ia supernovae consists of a carbon-oxygen (CO) white dwarf ( ~... more A currently favored model for Type Ia supernovae consists of a carbon-oxygen (CO) white dwarf ( ~ 0.6-1.0 M_sun), surrounded by a thick layer of helium ( ~ 0.2-0.3 M_sun), which explodes as a consequence of successive detonations in the helium layer and the CO core. Previous studies, carried out in one and two dimensions, have shown that this model is capable of providing light curves and late-time spectra in agreement with observations, though the peak light spectrum may be problematic. These same studies also highlighted a key uncertainty in the model. When properly considered in three dimensions, will the helium detonation actually succeed in igniting a corresponding detonation in the carbon core? In this paper we follow the hydrodynamic evolution of a representative case calculated in three dimensions using the smoothed particle (SPH) approach to multi-dimensional hydrodynamical modeling. Several fine zoned simulations are also carried out in one dimension to elucidate shock hyd...
The Astrophysical Journal, 1995
The Astrophysical Journal, 2012
In this paper we report on the bulk features of the hole carved by the companion star in the mate... more In this paper we report on the bulk features of the hole carved by the companion star in the material ejected during a Type Ia supernova explosion. In particular we are interested in the long term evolution of the hole as well as in its fingerprint in the geometry of the supernova remnant after several centuries of evolution, which is a hot topic in current Type Ia supernovae studies. We use an axisymmetric smoothed particle hydrodynamics code to characterize the geometric properties of the supernova remnant resulting from the interaction of this ejected material with the ambient medium. Our aim is to use supernova remnant observations to constrain the single degenerate scenario for Type Ia supernova progenitors. Our simulations show that the hole will remain open during centuries, although its partial or total closure at later times due to hydrodynamic instabilities is not excluded. Close to the edge of the hole, the Rayleigh-Taylor instability grows faster, leading to plumes that approach the edge of the forward shock. We also discuss other geometrical properties of the simulations, like the evolution of the contact discontinuity. Subject headings: supernova: general, supernova remnants spread the combustion to the whole mass of the star in a time scale of the order of a second, triggering a thermonuclear explosion. Hydrodynamic models of this kind of explosion suggest that the observed nucleosynthetic yields and kinetic energies are better explained if the deflagration turns into a detonation (i.e. supersonic burning) at some point, Höeflich & Khokhlov (1996), Gamezo, Khokhlov & Oran (2005), but a consensus theoretical model -4for Type Ia supernovae does not exist yet.
Nuclear Physics A, 2003
We present a straightforward integration method to compute the abundance and temperature evolutio... more We present a straightforward integration method to compute the abundance and temperature evolution in explosive scenarios. In this approach the thermal equation is implicitely coupled with chemical equations in order to avoid instabilities and ensure a gentle transition from the normal combustion regime to the quasi (QSE) and complete nuclear statistical equilibrium (NSE). Two nuclear networks, with 14 nuclei (α-network) and 86 nuclei (including protons and neutrons) respectively, have been considered. The scheme is suitable to cope with a variety of explosive burning regimes.
Supernovae: lights in the darkness, 2007
The signal of neutron star (NS) mergers has the imprint of the EOS of dense nuclear matter, which... more The signal of neutron star (NS) mergers has the imprint of the EOS of dense nuclear matter, which is still not well known. A set of gravitational waves (GW) signals have been calculated from 3D hydrodynamical simulations of NS-NS mergers using the Smoothed Particle Hydrodynamics technique (SPH) with different EOS. By analyzing the morphology and time evolution of the signal we want to be able to discriminate among the variety of proposed EOS after a successful GW detection has been done.
AIP Conference Proceedings, 1994
ESO ASTROPHYSICS SYMPOSIA, 2003
We present several hydrodynamical simulations of thermonuclear supernovae dealing with multiple d... more We present several hydrodynamical simulations of thermonuclear supernovae dealing with multiple delayed detonations. The calculations were carried out in three dimensions, making possible to study the influence of geometry of the flame front in two aspects. First, the evolution of its fractal dimension during the deflagration phase has been followed until a critical value is reached such that the deflagration may turn into a detonation. Second, as the resulting detonation could probably be scattered through the flame, the effect of its initial location on the detonation propagation, final energetics and nucleosynthesis has been explored.
We describe and check a novel formulation of Smoothed Particle Hydrodynamics (SPH) based on an In... more We describe and check a novel formulation of Smoothed Particle Hydrodynamics (SPH) based on an Integral Approach to the Derivatives, called IAD_0, 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 flows, and is less susceptible to the pairing instability. The resulting algorithm is verified 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.
Lecture Notes in Physics, 1989
ABSTRACT
Astronomy & Astrophysics, 2014
Context. The smoothed particle hydrodynamics (SPH) technique is a numerical method for solving ga... more Context. The smoothed particle hydrodynamics (SPH) technique is a numerical method for solving gas-dynamical problems that has been applied to simulate the evolution of a wide variety of astrophysical systems. The method has a second-order accuracy, with a resolution that is usually much larger in the compressed regions than in the diluted zones of the fluid. Aims. We propose and check a method to balance and equalize the resolution of SPH between high and low density regions. This method relies in the versatility of a family of interpolators called sinc kernels, which allows to increase the quality of interpolations just varying a single parameter (the exponent of the sinc function). Methods. The proposal is checked and validated through a number of numerical tests, going from standard onedimensional Riemann problems in shock tubes, to multidimensional simulations of explosions, hydrodynamic instabilities and the collapse of a sun-like polytrope.
Thermonuclear Supernovae, 1997
The Astrophysical Journal, 1995
Some results of a set of tridimensional calculations concerning the explosion of a white dwarf by... more Some results of a set of tridimensional calculations concerning the explosion of a white dwarf by means of a smooth particle hydrodynamics (SPH) code are presented. The burning front advance is solved along with the hydrodynamics of the whole star, and a characterization of the front surface in terms of fractal concepts is done. Our main result indicates that the surface of the deflagration front sought at the largest scales of the Rayleigh-Taylor instability can be characterized as a fractal with a time-dependent dimension, D(t), whose value is 2 Յ D(t) Յ 2.4.
Astrophysics and Space Science Library, 1997