Related papers: Ultra-faint dwarfs in a Milky Way context: Introdu…
We use observations of ultra-faint dwarf (UFD) galaxies to constrain the particle mass of ultra-light dark matter. Potential fluctuations created by wave interference in virialized "fuzzy" dark matter (FDM) halos dynamically heat stellar…
Cosmological simulations of galaxy clusters are unable to resolve dwarf galaxies due to limited numerical resolution which drives the artificial disruption of dark matter substructures. We address these limitations by combining the results…
We present a new method for generating initial conditions for LCDM N-body simulations which provides the dynamical range necessary to follow the evolution and distribution of the fossils of the first galaxies on Local Volume, 5-10 Mpc,…
We test if the cosmological zoom-in simulations of isolated galaxies from the FIRE project reproduce the properties of ultra diffuse galaxies. We show that stellar feedback-generated outflows that dynamically heat galactic stars, together…
We present Keck/DEIMOS spectroscopy of stars in 8 of the newly discovered ultra-faint dwarf galaxies around the Milky Way. We measure the velocity dispersions of Canes Venatici I and II, Ursa Major I and II, Coma Berenices, Hercules, Leo IV…
Ultrafaint dwarf galaxies (UFDs) are typically assumed to have simple, stellar populations with star formation ending at reionization. Yet as the observations of these galaxies continue to improve, their star formation histories (SFHs) are…
The density profiles of dwarf galaxies are a highly varied set. If the dark matter is an ultra-light particle such as axions, then simulations predict a distinctive and unique profile. If the axion mass is large enough to fit the…
We present the lifetime star formation histories (SFHs) for six ultra-faint dwarf (UFD; $M_V>-7.0$, $ 4.9<\log_{10}({M_*(z=0)}/{M_{\odot}})<5.5$) satellite galaxies of M31 based on deep color-magnitude diagrams constructed from…
Ultra-faint dwarf galaxies (UFDs) show extreme dynamical mass-to-light ratios of approximately 100-5000 in solar units within the half-light radius, making them critical tests for cosmological models. However, it is a concern whether the…
The Milky Way has accreted many ultra-faint dwarf galaxies (UFDs), and stars from these galaxies can be found throughout our Galaxy today. Studying these stars provides insight into galaxy formation and early chemical enrichment, but…
The very large (100-1000) mass-to-light ratio applicable to the ultra-faint dwarf galaxies (UFDs) implies a high concentration of dark matter, thus rendering them ideal theatres for indirect signatures of dark matter. In this paper, we…
We present uniformly measured resolved stellar photometry and star formation histories (SFHs) for 36 nearby ($\lesssim$ 400 kpc) ultra-faint dwarf galaxies (UFDs; $-7.1 \le M_V \le +0.0$) from new and archival HST imaging. We measure…
The faintest Local Group galaxies found lurking in and around the Milky Way halo provide a unique test bed for theories of structure formation and evolution on small scales. Deep Subaru and Hubble Space Telescope photometry demonstrates…
We present new constraints on the star formation histories of the ultra-faint dwarf (UFD) galaxies, using deep photometry obtained with the Hubble Space Telescope (HST). A galaxy class recently discovered in the Sloan Digital Sky Survey,…
We investigate the nature of Ultra Faint dwarf spheroidal galaxies (UF dSphs) in a general cosmological context, simultaneously accounting for various "classical" dSphs and Milky Way (MW) properties, including their Metallicity Distribution…
We present uniformly measured stellar metallicities for 463 stars in 13 Milky Way (MW) ultra-faint dwarf galaxies (UFDs; $M_V = -7.1$ to $-0.8$) using narrowband CaHK (F395N) imaging taken with the Hubble Space Telescope (HST). This…
Unraveling the nature of dark matter (DM) stands as a primary objective in modern physics. Here we present evidence suggesting deviations from the collisionless Cold DM (CDM) paradigm. It arises from the radial distribution of stars in six…
Ultra-faint dwarf galaxies (UFDs) are newcomers among galaxies, and are the faintest galaxies in the observed universe. To date, they have only been found around the Milky Way Galaxy and M31 in the Local Group. We present the discovery of…
Over the past five years, searches in Sloan Digital Sky Survey data have more than doubled the number of known dwarf satellite galaxies of the Milky Way, and have revealed a population of ultra-faint galaxies with luminosities smaller than…
We test the luminosity function of Milky Way satellites as a constraint for the nature of Dark Matter particles. We perform dissipationless high-resolution N-body simulations of the evolution of Galaxy-sized halo in the standard Cold Dark…