A5084079518- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Nuclear Physics and Applications
- Cosmology and Gravitation Theories
- High-pressure geophysics and materials
- Astronomical Observations and Instrumentation
- Nuclear physics research studies
- Galaxies: Formation, Evolution, Phenomena
- Particle Detector Development and Performance
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Particle physics theoretical and experimental studies
- Geophysics and Gravity Measurements
- Radiation Detection and Scintillator Technologies
- Scientific Research and Discoveries
- Advanced Semiconductor Detectors and Materials
- Solar and Space Plasma Dynamics
- Particle Accelerators and Free-Electron Lasers
Institut d'Estudis Espacials de Catalunya
2013-2024
Institute of Space Sciences
2014-2024
Pompeu Fabra University
2024
Reial Acadèmia de Ciències i Arts de Barcelona
2017-2024
Florida State University
2022
AZTERLAN
2019
Sciences et Ingénierie de la Matière Molle
2018
Institute for Space Astrophysics and Planetology
2018
Universidad de Cádiz
2018
American Society for Radiation Oncology
2018
The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO look for axions or axion-like particles (ALPs) originating in the Sun via Primakoff conversion of solar plasma photons. In terms signal-to-noise ratio, about 4–5 orders magnitude more sensitive than CAST, currently most powerful helioscope, reaching sensitivity to axion-photon couplings down few × 10−12 GeV−1 and thus probing large fraction unexplored ALP parameter space....
The initial–final mass relationship connects the of a white dwarf with its progenitor in main sequence. Although this function is fundamental importance to several fields modern astrophysics, it not well constrained either from theoretical or observational points view. In work, we revise present semi-empirical by re-evaluating available data. distribution obtained grouping all our results presents considerable dispersion, which larger than uncertainties. We have carried out weighted...
It has been shown that the shape of luminosity function white dwarfs (WDLF) is a powerful tool to check for possible existence DFSZ-axions, proposed but not yet detected type weakly interacting particles. With aim deriving new constraints on axion mass, we compute in this paper theoretical WDLFs basis WD evolving models incorporate feedback axions thermal structure dwarf. We find impact emission into neutrino can be neglected at high luminosities M Bol≲ 8) and needs incorporated...
White dwarfs are the end product of lives intermediate- and low-mass stars their evolution is described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision luminosity function, that is, number per unit volume interval. We show here shape bright branch this function only sensitive averaged rate white we propose use property check existence axions, proposed but not yet detected weakly interacting particle. Our results indicate inclusion...
<i>Context. <i/>The coalescence of two white dwarfs is the final outcome a sizeable fraction binary stellar systems. Moreover, this process has been proposed to explain several interesting astrophysical phenomena.<i>Aims. <i/>We present results set high-resolution simulations merging dwarfs.<i>Methods. use an up-to-date smoothed particle hydrodynamics code that incorporates very detailed input physics and improved treatment artificial viscosity. Our have done using large number particles...
High-field magnetic white dwarfs have been long suspected to be the result of stellar mergers. However, nature coalescing stars and precise mechanism that produces field are still unknown. Here, we show hot, convective, differentially rotating corona present in outer layers remnant merger two degenerate cores can produce fields required strength do not decay for timescales. Using a state-of-the-art Monte Carlo simulator, also expected number high-field produced this way is consistent with...
In this paper we compute detailed evolutionary models providing chemical profiles for white dwarfs having progenitors in the mass range from 1.0 to $7 M_{\sun}$ and examine influence of such cooling process. The process separation carbon oxygen during crystallization is decreased as a consequence initial stratification, but it still important cannot be neglected. As an example, best fit luminosity functions Liebert et al. (1988) Oswalt (1996) gives age disk 9.3 11.0 Gyr, respectively, when...
We present new spectroscopic observations for a sample of C(N)-type red giants. These objects belong to the class Asymptotic Giant Branch stars, experiencing thermal instabilities in He-burning shell (thermal pulses). Mixing episodes called third dredge-up enrich photosphere with newly synthesized C12 He-rich zone, and this is source high observed ratio between carbon oxygen (C/O > 1 by number). Our abundance estimates confirm that, agreement general understanding late evolutionary stages...
We present the first detailed and homogeneous analysis of s-element content in Galactic carbon stars N type. Abundances Sr, Y, Zr (low-mass s-elements, or ls), Ba, La, Nd, Sm, Ce (high-mass hs) are derived using spectral synthesis technique from high-resolution spectra. The analyzed nearly solar metallicity show moderate enhancements, similar to those found S stars, but smaller than only previous study (Utsumi 1985), also supergiant post-asymptotic giant branch (post-AGB) stars. This is...
view Abstract Citations (141) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Cooling Theory of Crystallized White Dwarfs Segretain, L. ; Chabrier, G. Hernanz, M. Garcia-Berro, E. Isern, J. Mochkovitch, R. We examine extensively the effect different crystallization related to presence major and minor chemical species, on binding energy cooling time old white dwarfs. use improved equations state for solid liquid, diagrams calculated within...
Recent high-redshift type-Ia supernovae results can be used to set new bounds on a possible variation of the gravitational constant G. If local value G at space-time location distant is different, it would change both kinetic energy release and amount ${}^{56}\mathrm{Ni}$ synthesized in supernova outburst. Both effects are related Chandrasekhar mass ${M}_{\mathrm{Ch}}\ensuremath{\propto}{G}^{\ensuremath{-}3/2}.$ In addition, integrated with time also affect cosmic evolution therefore...
We present the results of three-dimensional Smoothed Particle Hydrodynamics (SPH) calculations process coalescence white dwarfs. follow in detail initial phase merging for several masses primary and secondary binary system. Special attention has been paid to issue whether or not thermonuclear runaway occurs during merging. find that although relatively high temperatures are attained most violent process, flash is rapidly quenched. The total mass lost by system also small (of order 0.5% at...
view Abstract Citations (117) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Axion Cooling of White Dwarfs Isern, J. ; Hernanz, M. Garcia-Berro, E. To investigate the effect axions in cooling process white dwarfs, their luminosity function was computed way described by Isern et al. (1991), but neglecting sedimentation induced solidification which can introduce a considerable delay process. It found that is only modified region luminosities,...
We present a new set of cooling models and isochrones for both H- He-atmosphere white dwarfs (WDs), incorporating accurate boundary conditions from detailed model atmosphere calculations, carbon–oxygen chemical abundance profiles based on updated stellar evolution calculations the BaSTI archive—a theoretical data center Virtual Observatory. discuss quantify uncertainties in times predicted by models, arising treatment mixing during central He-burning phases, number thermal pulses experienced...
We employ a state-of-the-art asteroseismological model of G117-B15A, the archetype H-rich atmosphere (DA) white dwarf pulsators (also known as DAV or ZZ Ceti variables), and use most recently measured value rate period change for dominant mode this pulsating star to derive new constraint on mass axion, still conjectural non-barionic particle considered candidate dark matter Universe. Assuming that G117-B15A is truly represented by our model, in particular, associated pulsation g-mode trapped...
Isolated magnetic white dwarfs have field strengths ranging from kilogauss to gigagauss. However, the origin of has not been hitherto elucidated. Whether these fields are fossil, hence remnants original weak amplified during course evolution their progenitor stars, or result binary interactions or, finally, they produced by other internal physical mechanisms cooling dwarf itself, remains a mystery. At sufficiently low temperatures crystallize. Upon solidification, phase separation its main...