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Related papers: Ultra-faint dwarfs in a Milky Way context: Introdu…

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We develop a technique to investigate the possibility that some of the recently discovered ultra-faint dwarf satellites of the Milky Way might be cusp caustics rather than gravitationally self-bound systems. Such cusps can form when a…

Astrophysics of Galaxies · Physics 2011-01-19 Adi Zolotov , David W. Hogg , Beth Willman

We present a new formalism designed to discover dark matter annihilation occurring in the Milky Way's dwarf galaxies. The statistical framework extracts all available information in the data by simultaneously combining observations of all…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-28 Alex Geringer-Sameth , Savvas M. Koushiappas , Matthew G. Walker

Deep, wide-area photometric surveys have uncovered a population of compact ($r_{1/2} \approx$ 1-15 pc), extremely-low-mass ($M_* \approx$ 20-4000 $M_{\odot}$) stellar systems in the Milky Way halo that are smaller in size than known…

We demonstrate how the least luminous galaxies in the Universe, ultra-faint dwarf galaxies, are sensitive to their dynamical mass at the time of cosmic reionization. We select a low-mass ($\sim \text{1.5} \times 10^{9} \, \text{M}_{\odot}$)…

We predict the spatial distribution and number of Milky Way dwarf galaxies to be discovered in the DES and LSST surveys, by completeness correcting the observed SDSS dwarf population. We apply most massive in the past, earliest forming, and…

Astrophysics of Galaxies · Physics 2015-06-22 Jonathan R. Hargis , Beth Willman , Annika H. G. Peter

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], abundance ratios for 61 individual red giant branch stars…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Luis C. Vargas , Marla Geha , Evan N. Kirby , Joshua D. Simon

We use \texttt{GRUMPY}, a simple regulator-type model for dwarf galaxy formation and evolution, to forward model the dwarf galaxy satellite population of the Milky Way (MW) using the Caterpillar zoom-in simulation suite. We show that…

Astrophysics of Galaxies · Physics 2022-09-14 Viraj Manwadkar , Andrey Kravtsov

We have obtained deep Hubble Space Telescope (HST) imaging of four faint and ultra-faint dwarf galaxy candidates in the vicinity of M101 - Dw21, Dw22, Dw23 and Dw35, originally discovered by Bennet et al. (2017). Previous distance estimates…

Astrophysics of Galaxies · Physics 2020-04-15 P. Bennet , D. J. Sand , D. Crnojevic , K. Spekkens , A. Karunakaran , D. Zaritsky , B. Mutlu-Pakdil

Ultra-faint dwarf galaxies (UFDs) are commonly found in close proximity to the Milky Way and other massive spiral galaxies. As such, their projected stellar ellipticity and extended light distributions are often thought to owe to tidal…

The long term time evolution of tidal dwarf satellite galaxies with two different initial densities orbiting a host galaxy that resembles the Milky Way has been studied using a large set of Newtonian N-Body simulations. From the simulations…

Astrophysics of Galaxies · Physics 2016-02-11 R. A. Casas , V. Arias , K. Pena Ramírez , P. Kroupa

The dwarf galaxy companions to the Milky Way are unique cosmological laboratories. With luminosities as low as 10^-7 L_MW, they inhabit the lowest mass dark matter halos known to host stars and are presently the most direct tracers of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Beth Willman

Interpretation of data from faint dwarf galaxies is made challenging by observations limited to only the brightest stars. We present a major improvement to tackle this challenge by undertaking zoomed cosmological simulations that resolve…

We present ultra-high resolution cosmological hydrodynamic simulations of $M_*\simeq10^{4-6.3}M_{\odot}$ dwarf galaxies that form within $M_{v}=10^{9.5-10}M_{\odot}$ dark matter halos. Our simulations rely on the FIRE implementation of star…

Recent observations have reignited interest in a population of dwarf galaxies that are large and diffuse for their mass, often called ultra-diffuse galaxies. However, the origin and evolution of these mass-size outliers and the role of the…

Astrophysics of Galaxies · Physics 2023-09-12 Jiaxuan Li , Jenny E. Greene , Johnny Greco , Rachael Beaton , Shany Danieli , Andy Goulding , Song Huang , Erin Kado-Fong

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 appear to be an extension of the classical dwarf spheroidals to…

Ultracool dwarfs represent a significant proportion of stars in the Milky Way,and deep samples of these sources have the potential to constrain the formation history and evolution of low-mass objects in the Galaxy. Until recently, spectral…

The dependence of the stellar initial mass function (IMF) on star-formation environment, particularly at low metallicities and high redshifts, remains poorly constrained. Ultra-faint dwarf galaxies (UFDs) are local fossils of high-redshift…

[Abridged]Ultra-faint dwarfs (UFDs) are expected to be the relics of the earliest galaxies forming in the Universe. Observations show the presence of a stellar halo around them, which can give precious insights into the evolution of UFDs.…

Astrophysics of Galaxies · Physics 2025-01-29 Lapo Querci , Andrea Pallottini , Lorenzo Branca , Stefania Salvadori

We use the second Gaia data release to investigate the kinematics of 17 ultra-faint dwarf galaxies (UFDs) and 154 globular clusters (GCs) in the Milky Way, focusing on the differences between static and evolving models of the Galactic…

Astrophysics of Galaxies · Physics 2020-12-08 Benjamin M. Armstrong , Kenji Bekki , Aaron D. Ludlow

We consider the extraction of parameters of dark matter halos hosting ultra-faint dwarf galaxies, in the case where there are only ${\cal O}(10)$ identified member stars with measured line-of-sight velocities. This scenario is likely to be…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-07 Levi K. C. Fisher , Isabelle S. Goldstein , Jason Kumar , Louis E. Strigari