Related papers: Simulating a White Dwarf-dominated Galactic Halo
Halo initial mass functions (IMFs), heavily-biased toward white dwarf (WD) precursors (i.e. 1->8 M_sun), have been suggested as a suitable mechanism for explaining microlensing statistics along the line of sight to the LMC. Such IMFs can…
Halo initial mass functions (IMFs) heavily biased toward white dwarf (WD) precursors ~1-8 Msun have been suggested as a suitable mechanism for explaining MACHO events. However, by simple chemical evolution argument, Gibson & Mould (1997;…
The suggestion that roughly half the mass of the galactic halo might be in the form of white dwarfs, together with the limits on the infrared background light and on the initial metallicity of the galactic disk, would set strong constraints…
Motivated by recent measurements which suggest that roughly half the mass of the galactic halo may be in the form of white dwarfs, we study the implications of such a halo. We first use current limits on the infrared background light and…
I present a new Galactic chemical evolution model motivated by and grounded in the hierarchical theory of galaxy formation, as expressed by a halo merger history of the Galaxy. This model accurately reproduces the "metallicity distribution…
Using stellar population synthesis techniques, we explore the photometric signatures of white dwarf progenitor dominated galactic halos, in order to constrain the fraction of halo mass that may be locked-up in white dwarf stellar remnants.…
We examine the chemical abundance constraints on a population of white dwarfs in the Halo of our Galaxy. We are motivated by microlensing evidence for massive compact halo objects (Machos) in the Galactic Halo, but our work constrains white…
The gravitational microlensing experiments in the direction of Large Magellanic Cloud (LMC) predict a large amount of white dwarfs ($\sim 20%$) filling the galactic halo. However, the predicted white dwarfs have not been observed at the…
Halo white dwarfs can provide important information about the properties and evolution of the galactic halo. In this paper we compute, assuming a standard IMF and updated models of white dwarf cooling, the expected luminosity function, both…
Observations have not yielded convincing results concerning the form of the stellar initial mass function (IMF) or its variations in space and time, so it is proposed that theoretical models may provide useful guidance. Several classes of…
It has frequently been suggested that the stellar IMF in galaxies was top-heavy at early times. This would be plausible physically if the IMF depends on a mass scale such as the Jeans mass that was higher at earlier times because of the…
The contribution of white dwarfs of the different Galactic populations to the stellar content of our Galaxy is only poorly known. Some authors claim a vast population of halo white dwarfs, which would be in accordance with some…
Recent observations suggest the existence of a white dwarf population in the Galactic halo, while others suggest that deuterium has been astrated in systems at high redshift and low metallicity. We propose that these observations could be…
(Abridged Abstract) A favored interpretation of recent microlensing measurements towards the Large Magellanic Cloud implies that a large fraction (i.e. 10--50%) of the mass of the galactic halo is composed of white dwarfs. We compare model…
The galactic halo likely grew over time in part by assembling smaller galaxies, the so-called building blocks. We investigate if the properties of these building blocks are reflected in the halo white dwarf (WD) population in the Solar…
The nature of the several microlensing events observed by the MACHO team towards the Large Magellanic Cloud (LMC) is still a subject of debate. Low-mass substellar objects and stars with masses larger than ~M_{sun} have been ruled out as…
Oppenheimer et al. (2001) have argued recently that at least 2% of the Galactic halo is comprised of white dwarfs If true, this finding has crucial implications for understanding the formation and evolution of the Milky Way. We draw…
We study the mass spectrum of destroyed dwarfs that contribute to the accreted stellar mass of Milky Way (MW) mass M_vir ~ 10^12.1 M_sun) halos using a suite of 45 zoom-in, dissipationless simulations. Empirical models are employed to…
One of the most robust observations of the stellar initial mass function (IMF) is its near-universality in the Milky Way and neighboring galaxies. But recent observations of early-type galaxies can be interpreted to imply a bottom-heavy…
In this work we explore the effects of adopting initial mass functions (IMFs) variable in time on the chemical evolution of the Galaxy. In order to do that we adopt a chemical evolution model which assumes two main infall episodes for the…