相关论文: Simulating a White Dwarf-dominated Galactic Halo

In two previous papers, we presented simulations of the first galaxies in a representative volume of the Universe. The simulations are unique because we model feedback-regulated galaxy formation, using time-dependent,…

Most structural and evolutionary properties of galaxies strongly rely on the stellar initial mass function (IMF), namely the distribution of the stellar mass formed in each episode of star formation. As the IMF shapes the stellar population…

I present a literature search through 31 July 1997 of white dwarfs (WDs) in open and globular clusters. There are 36 single WDs and 5 WDs in binaries known among 13 open clusters, and 340 single WDs and 11 WDs in binaries known among 11…

In the context of the star formation through the fragmentation of an extremely metal-deficient protogalactic cloud, the gravitational collapse of filamentary gas clouds is explored with H$_2$ and HD chemistry. It is found by 1D…

We revisit the properties and astrophysical implications of the field white dwarf mass distribution in preparation of Gaia applications. Our study is based on the two samples with the best established completeness and most precise…

It is well-established that the vast majority of metal-poor Galactic halo stars shows evidence for enrichment by solely massive stars. Recent observations have identified more varied behavior in the pattern of elemental abundances measured…

The microlensing experiments in the direction of the LMC seem to be indicating that about 60% of the dark matter in the Galactic halo is tied up in objects whose masses are about half the mass of the Sun. This mass is a natural one for old…

(Abridged) The hierarchical formation scenario for the stellar halo requires the accretion and disruption of dwarf galaxies, yet low-metallicity halo stars are enriched in alpha-elements compared to similar, low-metallicity stars in dwarf…

We use recent microlensing observations toward the central bulge of the Galaxy to probe the overall stellar plus brown dwarf initial mass function (IMF) in these regions well within the brown dwarf domain. We find that the IMF is consistent…

We study the stellar population history and chemical evolution of the Milky Way (MW) in a hierarchical LCDM model for structure formation. Using a Monte Carlo method based on the semi-analytical EPS formalism, we reconstruct the merger tree…

We use magneto-hydrodynamical simulations of Milky Way-mass haloes from the Auriga project to examine the properties of surviving and destroyed dwarf galaxies that are accreted by these haloes over cosmic time. We show that the combined…

Recent observational evidence for initial mass function (IMF) variations in massive quiescent galaxies at $z = 0$ challenges the long-established paradigm of a universal IMF. While a few theoretical models relate the IMF to birth cloud…

All previous attempts to understand the microlensing results towards the Large Magellanic Cloud (LMC) have assumed homogeneous present day mass functions (PDMFs) for the lensing populations. Here, we present an investigation into the…

This paper reports preliminary yet compelling kinematical inferences for N ~ 600 carbon-rich dwarf stars that demonstrate around 30% to 60% are members of the Galactic halo. The study uses a spectroscopically and non-kinematically selected…

The stellar initial mass function (IMF) is commonly assumed to be an invariant probability density distribution function of initial stellar masses being represented by the canonical IMF. As a consequence the galaxy-wide IMF (gwIMF), defined…

We present evidence for the existence of an old stellar halo in the dwarf irregular galaxy WLM, an isolated member of the Local Group. The halo consists of population-II stars, with low metallicities and age $\geq 10^{10}$yr. The finding of…

Observations with JWST have revealed an unexpected high abundance of bright z>10 galaxy candidates. We explore whether a stellar initial mass function (IMF) that becomes increasingly top-heavy towards higher redshifts and lower gas-phase…

It is shown that the low metallicity tail of the stellar metallicity distribution predicted by simple Outflow models for the Milky Way halo depends sensitively on whether Instantaneous Recycling is adopted or relaxed. In both cases, current…

We use Gaia DR2 to measure the initial mass function (IMF) of stars within 250 pc and masses in the range 0.2 < m/Msun < 1.0, separated according to kinematics and metallicity, as determined from Gaia transverse velocity, v_T, and location…

The recently inferred variations in the stellar initial mass function (IMF) among local high-mass early-type galaxies may require a reinterpretation of observations of galaxy populations and may have important consequences for the…