I will give an overview of recent work on the spectroscopic chemical abundance surveys of dwarf galaxies in and around the Milky Way. I will make use of recent results from Gaia DR2 and show how they enhance our understanding of dwarf galaxies, both large and small, combined with ongoing VLT follow-up projects. I will assess how this fits in with an overall view of the chemo-dynamical...
Elemental abundances and isotopic ratios of stars in the Milky Way Galaxy have provided stringent constraints on the formation and evolutionary history of the Galaxy. It is now possible to apply this Galactic archaeology approach for other galaxies where elemental abundances of stellar populations can be measured within galaxies with IFU surveys. I will give an overview of Galactic and cosmic...
The dwarf galaxies in the Local Group are excellent laboratories for studying the creation of the elements (nucleosynthesis) and the build-up of those elements over time (chemical evolution). The galaxies' proximity permits spectroscopy of individual stars, from which detailed elemental abundances can be measured. Their small sizes and, in some cases, short star formation lifetimes imprinted...
We investigate the star formation histories and chemical evolution of isolated analogs of Local Group untrafaint dwarf galaxies (UFDs) and gas-rich, low-mass dwarfs. We perform a suite of cosmological hydrodynamic zoom-in simulations to follow their evolution from the era of the first generation of stars down to z = 0. We confirm that reionization, combined with supernova (SN) feedback, is...
JWST will uncover a vast population of low-luminosity galaxies at Cosmic Dawn that is responsible for most of reionization. We present predictions for this high-redshift population, using two suites of high-resolution cosmological simulations -- the Renaissance Simulations and the Tempest Simulations -- that sample different large-scale environments. The Tempest Simulations specifically...
The Galactic halo is expected to contain signatures of past galaxy accretions. In fact, the kinematics of halo stars in the Gaia DR2 clearly shows the presence of a massive accreted galaxy. We search for signatures of other less-massive galaxies through the combination of chemical abundances and kinematics of metal-poor stars by using the data from the SAGA database, LAMOST DR4, and APOGEE....
Modern cosmological simulations suggest that the hierarchical assembly of dark matter halos provided the gravitational wells that allowed the primordial gases to form stars and galaxies inside them. The first galaxies comprised of the first systems of stars gravitationally bound in dark matter halos are naturally recognized as the building blocks of early Universe. To understand the formation...
The stellar halo and tidal streams of M31 provide an essential counterpoint to the same structures around the Galaxy. While Galactic measurements of [Fe/H] and [$\alpha$/Fe] have been made, little is known about the detailed chemical abundances of the M31 system. To make progress with existing telescopes, we apply spectral synthesis to low-resolution spectroscopy (R $\sim$ 2500 at 7000...
Substructures such as stellar streams are the important tracers that record how the host halos accreted progenitor galaxies. To investigate the relationship between structural properties of substructures and orbits of their progenitors, we combine semi-analytic models with a high-resolution cosmological N-body simulation and analyze the statistical properties of substructures around Milky...
Understanding the metal mixing in galaxies is a cornerstone to extract the signatures of first stars. Recent high-dispersion spectroscopic observations significantly widen our understanding of elemental abundances in metal-poor stars. Second generation stars inherit the abundances of nucleosynthetic signatures from first stars mixed in the interstellar medium. Here we show that abundances of...
Ultra-faint dwarf galaxies are some of the oldest systems ($\sim$13Gyr) in the Milky Way halo. Studying the metallicities of their stars can place strong constraints on models of early chemical enrichment. Spectroscopy only permits the detailed chemical characterization of a handful of stars per system. This under-sampling has led to open questions such as whether the most metal-poor stars...
