337 citations · 842 across the 11 of their papers we have counts for
11 papers
Evidence of a non universal stellar Initial Mass Function. Insights from HST optical imaging of 6 Ultra Faint Dwarf Milky Way Satellites
Mario Gennaro, Kirill Tchernyshyov, Thomas M. Brown +9
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…
[/Fe] Abundances of Four Outer M 31 Halo Stars
Luis C. Vargas, Karoline M. Gilbert, Marla C. Geha +3
We present alpha element to iron abundance ratios, [/Fe], for four stars in the outer stellar halo of the Andromeda Galaxy (M 31). The stars were identified as high-likelihood f…
The Quenching of the Ultra-Faint Dwarf Galaxies in the Reionization Era
Thomas M. Brown, Jason Tumlinson, Marla Geha +11
We present new constraints on the star formation histories of six ultra-faint dwarf galaxies: Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I. Our a…
The Distribution of Alpha Elements in Andromeda Dwarf Galaxies
Luis C. Vargas, Marla C. Geha, Erik J. Tollerud
We present alpha to iron abundance ratios for 226 individual red giant branch stars in nine dwarf galaxies of the Andromeda (M 31) satellite system. The abundances are measured fro…
Metallicity Evolution of the Six Most Luminous M31 Dwarf Satellites
N. Ho, M. Geha, E. Tollerud +3
We present global metallicity properties, metallicity distribution functions (MDFs) and radial metallicity profiles for the six most luminous M31 dwarf galaxy satellites: M32, NGC…
The Formation History of the Ultra-Faint Dwarf Galaxies
Thomas M. Brown, Jason Tumlinson, Marla Geha +11
We present early results from a Hubble Space Telescope survey of the ultra-faint dwarf galaxies. These Milky Way satellites were discovered in the Sloan Digital Sky Survey, and app…
The Outer Limits of the M31 System: Kinematics of the Dwarf Galaxy Satellites And XXVIII and And XXIX
Erik J. Tollerud, Marla C. Geha, Luis C. Vargas +1
We present Keck/DEIMOS spectroscopy of resolved stars in the M31 satellites And XXVIII & And XXIX. We show that these are likely self-bound galaxies based on 18 and 24 members in A…
The Distribution of Alpha Elements in Ultra-Faint Dwarf Galaxies
Luis C. Vargas, Marla Geha, Evan N. Kirby +1
The Milky Way ultra-faint dwarf galaxies (UFDs) contain some of the oldest, most metal-poor stars in the Universe. We present [Mg/Fe], [Si/Fe], [Ca/Fe], [Ti/Fe], and mean [alpha/Fe…
The Discovery of an Ultra-Faint Star Cluster in the Constellation of Ursa Minor
Ricardo R. Munoz, Marla Geha, Patrick Cote +5
We report the discovery of a new ultra-faint globular cluster in the constellation of Ursa Minor, based on stellar photometry from the MegaCam imager at the Canada-France-Hawaii Te…
Segue 3: An Old, Extremely Low luminosity Star Cluster in the Milky Way's Halo
Ross Fadely, Beth Willman, Marla Geha +6
We investigate the kinematic and photometric properties of the Segue 3 Milky Way companion using Keck/DEIMOS spectroscopy and Magellan/IMACS g and r-band imaging. Using maximum lik…
The uvbyHbeta Metallicity Calibration for G and K Dwarfs
B. A. Twarog, L. C. Vargas, B. J. Anthony-Twarog
The metallicity dependence of the primary indices of the uvby photometric system for cooler dwarfs (Teff ~ 6500 K to 5000K) is investigated. The data base for the analysis is compo…