The contribution of oxygen-neon white dwarfs to the MACHO content of the Galactic halo

Context. The interpretation of microlensing results towards the Large Magellanic Cloud (LMC) still remains controversial. White dwarfs have been proposed to explain these results and, hence, to contribute significantly to the mass budget of our Galaxy. However, several constraints on the role played...

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Detalles Bibliográficos
Autores principales: Camacho, J., Torres, S., Isern, J., Althaus, Leandro Gabriel, García-Berro, E.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2007
Materias:
Ciencias Astronómicas
Galaxy: halo
Galaxy: stellar content
Galaxy: structure
Stars: luminosity function, mass function
Stars: white dwarfs
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/83215
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-83215
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
Galaxy: halo
Galaxy: stellar content
Galaxy: structure
Stars: luminosity function, mass function
Stars: white dwarfs
spellingShingle Ciencias Astronómicas
Galaxy: halo
Galaxy: stellar content
Galaxy: structure
Stars: luminosity function, mass function
Stars: white dwarfs
Camacho, J.
Torres, S.
Isern, J.
Althaus, Leandro Gabriel
García-Berro, E.
The contribution of oxygen-neon white dwarfs to the MACHO content of the Galactic halo
topic_facet Ciencias Astronómicas
Galaxy: halo
Galaxy: stellar content
Galaxy: structure
Stars: luminosity function, mass function
Stars: white dwarfs
description Context. The interpretation of microlensing results towards the Large Magellanic Cloud (LMC) still remains controversial. White dwarfs have been proposed to explain these results and, hence, to contribute significantly to the mass budget of our Galaxy. However, several constraints on the role played by regular carbon-oxygen white dwarfs exist. Aims. Massive white dwarfs are thought to be made of a mixture of oxygen and neon. Correspondingly, their cooling rate is larger than those of typical carbon-oxygen white dwarfs and they fade to invisibility in short timescales. Consequently, they constitute a good candidate for explaining the microlensing results. Methods. Here, we examine in detail this hypothesis by using the most recent and up-to-date cooling tracks for massive white dwarfs and a Monte Carlo simulator which takes into account the most relevant Galactic inputs. Results. We find that oxygen-neon white dwarfs cannot account for a substantial fraction of the microlensing depth towards the LMC, independently of the adopted initial mass function, although some microlensing events could be due to oxygen-neon white dwarfs. Conclusions. The white dwarf population contributes at most a 5% to the mass of the Galactic halo.
format Articulo
Articulo
author Camacho, J.
Torres, S.
Isern, J.
Althaus, Leandro Gabriel
García-Berro, E.
author_facet Camacho, J.
Torres, S.
Isern, J.
Althaus, Leandro Gabriel
García-Berro, E.
author_sort Camacho, J.
title The contribution of oxygen-neon white dwarfs to the MACHO content of the Galactic halo
title_short The contribution of oxygen-neon white dwarfs to the MACHO content of the Galactic halo
title_full The contribution of oxygen-neon white dwarfs to the MACHO content of the Galactic halo
title_fullStr The contribution of oxygen-neon white dwarfs to the MACHO content of the Galactic halo
title_full_unstemmed The contribution of oxygen-neon white dwarfs to the MACHO content of the Galactic halo
title_sort contribution of oxygen-neon white dwarfs to the macho content of the galactic halo
publishDate 2007
url http://sedici.unlp.edu.ar/handle/10915/83215
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