Related papers: Simulating a White Dwarf-dominated Galactic Halo
The chemical abundances measured in stars of the Galactic bulge offer an unique opportunity to test galaxy formation models as well as impose strong constraints on the history of star formation and stellar nucleosynthesis. The aims of this…
Intermediate Mass Black Holes (IMBHs; 10^1.3-5 M_sun) are thought to form as relics of Population III stars or from the runaway collapse of stars in young clusters; their number and very existence are uncertain. We ran N-body simulations of…
Dwarf galaxies generally follow a mass-metallicity (MZ) relation, where more massive objects retain a larger fraction of heavy elements. Young tidal dwarf galaxies (TDGs), born in the tidal tails produced by interacting gas-rich galaxies,…
A model for Galactic chemical evolution, driven by supernova-induced star formation, is formulated and used to examine the nature of the Galactic halo at early epochs. In this model, new stars are formed following each supernova event, thus…
Using deep HST/ACS observations, we demonstrate that the sub-solar stellar initial mass function (IMF) of 6 ultra-faint dwarf Milky Way Satellites (UFDs) is more bottom light than the IMF of the Milky Way disk. Our data have a lower mass…
Given a flurry of recent claims for systematic variations in the stellar initial mass function (IMF), we carry out the first inventory of the observational evidence using different approaches. This includes literature results, as well as…
We study the age and metallicity distribution function (MDF) of metal-poor stars in the Milky Way halo as a function of galactocentric radius by combining N-body simulations and semi-analytical methods. We find that the oldest stars…
We explore the connection between galaxies and dark matter halos in the Milky Way (MW) and quantify the implications on properties of the dark matter particle and the phenomenology of low-mass galaxy formation. This is done through a…
We are entering an era in which we will be able to detect and characterize hundreds of dwarf galaxies within the Local Volume. It is already known that a strong dichotomy exists in the gas content and star formation properties of field…
The dwarf spheroidal galaxy in Ursa Minor is apparently dark-matter dominated, and is of very low surface brightness, with total luminosity only equal to that of a globular cluster. Indeed its dominant stellar population is old and…
Observational studies are showing that the galaxy-wide stellar initial mass function are top-heavy in galaxies with high star-formation rates (SFRs). Calculating the integrated galactic stellar initial mass function (IGIMF) as a function of…
We present the non-local thermodynamic equilibrium (NLTE) abundances of up to 10 chemical species in a sample of 59 very metal-poor (VMP, -4 < [Fe/H] < -2) stars in seven dwarf spheroidal galaxies (dSphs) and in the Milky Way (MW) halo. Our…
The early chemical evolution of the Galaxy and the Universe is vital to our understanding of a host of astrophysical phenomena. Since the most metal-poor Galactic stars (with metallicities down to [Fe/H]\sim-5.5) are relics from the…
The distribution of stars and stellar remnants (white dwarfs, neutron stars, black holes) within globular clusters holds clues about their formation and long-term evolution, with important implications for their initial mass function (IMF)…
Molecular hydrogen allows cooling in primordial gas, facilitating its collapse into Population III stars within primordial halos. Lyman-Werner (LW) radiation from these stars can escape the halo and delay further star formation by…
The H alpha equivalent width (EW) is the ratio of the H alpha flux to the continuum at 6565{\AA}. In normal star forming galaxies the H alpha flux is dominated by reprocessed photons from stars with masses greater than 10 M_o and the…
We test the hypothesis that the classical and ultra-faint dwarf spheroidal satellites of the our Galaxy have been the building blocks of the Galactic halo by comparing their [O/Fe] and [Ba/Fe] vs. [Fe/H] patterns with the ones observed in…
Evidence supporting the hypothesis of an invariant stellar Initial Mass Function is strong and varied. The intra-cluster medium in rich clusters of galaxies is one of the few contrary locations where recent interpretations of the chemical…
The chemical evolution of the Milky Way is investigated using a dual-phase metal-enriched infall model in which primordial gas fuels the earliest epoch of star formation, followed by the ongoing formation of stars from newly accreted gas.…
In this work we analyze the dark matter (DM) fraction, $f_{DM}$, and mass-to-light ratio mismatch parameter, $\delta_{IMF}$ (computed with respect to a Milky-Way-like IMF), for a sample of 39 dwarf early-type galaxies (dEs) in the Virgo…