相关论文: Ultrafaint Dwarf Galaxies - the lowest mass relics…
Low-mass dwarf galaxies ($M_{\rm vir} \lesssim 10^9\rm\ M_\odot$) are fundamental cosmological building blocks, yet the physical processes driving their structural diversity remain poorly understood. Recent numerical simulations have…
We present high resolution simulations of an isolated dwarf spheroidal (dSph) galaxy between redshifts $z\sim10$ and $z\sim 4$, the epoch when several Milky Way dSph satellites experienced extended star formation, in order to understand in…
The observed luminosity function (LF) of satellite galaxies shows several interesting features that require a better understanding of gas-thermodynamic processes and feedback effects related to reionization and galaxy formation. In galaxy…
We present results from a fully cosmological, very high-resolution, LCDM "zoom-in" simulation of a group of seven field dwarf galaxies with present-day virial masses in the range M_vir=4.4e8-3.6e10 Msun. The simulation includes a blastwave…
The presence of primordial magnetic fields increases the minimum halo mass in which star formation is possible at high redshifts. Estimates of the dynamical mass of ultra-faint dwarf galaxies (UFDs) within their half-light radius constrain…
So far, numerical simulations of ultra-faint dwarf galaxies (UFDs) failed to properly reproduce the observed size-luminosity relation. In particular, no hydro-dynamical-run managed to form UFDs with a half light radius as small as 30 pc as…
Low mass galaxies in the Local Group are dominated by dark matter and comprise the well studied ``dwarf Spheroidal" (dSph) class, with typical masses of $10^{9-10}M_\odot$ and also the equally numerous ``ultra faint dwarfs" (UFD),…
We use the extremely high-resolution ($m_{\rm bary}=4\rm{M}_\odot$) LYRA cosmological galaxy formation simulations of six dwarf galaxies with $M_{\rm 200c}\sim10^9\rm{M}_\odot$ at $z=0$ to investigate their stellar assembly histories. Based…
The Milky Way is surrounded by dozens of ultra-faint (< $10^5$ solar luminosities) dwarf satellite galaxies. They are the surviving remnants of the earliest galaxies, as confirmed by their ancient (~13 billion years old) and chemically…
Our recently completed one billion particle Via Lactea II simulation of a Milky Way-sized dark matter halo resolves over 50,000 gravitationally bound clumps orbiting today within the virialized region of the main host. About 2,300 of these…
We use a combination of high-resolution gasdynamics simulations of high-redshift dwarf galaxies and dissipationless simulations of a Milky Way sized halo to estimate the expected abundance and spatial distribution of the dwarf satellite…
Using analytic arguments and a suite of very high resolution (10^3 Msun per particle) cosmological hydro-dynamical simulations, we argue that high redshift, z ~ 10, M ~ 10^8 Msun halos, form the smallest `baryonic building block' (BBB) for…
Recent observations have discovered a number of extremely gas-rich very faint dwarf galaxies possibly embedded in low-mass dark matter halos. We investigate star formation histories of these gas-rich dwarf ("almost dark") galaxies both for…
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,…
Since reionization prevents star formation in most halos below 3 x 10^9 solar masses, dwarf galaxies only populate a fraction of existing dark matter halos. We use hydrodynamic cosmological simulations of the Local Group to study the…
The smallest satellites of the Milky Way ceased forming stars during the epoch of reionization and thus provide archaeological access to galaxy formation at $z>6$. Numerical studies of these ultra-faint dwarf galaxies (UFDs) require…
The synthesis of $r$-process elements is known to involve extremely energetic explosions. At the same time, recent observations find significant $r$-process enrichment even in extremely small ultra-faint dwarf (UFD) galaxies. This raises…
The lowest luminosity (L < 10^5 L_sun) Milky Way satellite galaxies represent the extreme lower limit of the galaxy luminosity function. These ultra-faint dwarfs are the oldest, most dark matter-dominated, most metal-poor, and least…
The scenario consistent with a wealth of observations for the missing mass problem is that of weakly interacting dark matter particles. However, arguments or proposals for a Newtonian or relativistic modified gravity scenario continue to be…
We place limits on dark matter made up of compact objects significantly heavier than a solar mass, such as MACHOs or primordial black holes (PBHs). In galaxies, the gas of such objects is generally hotter than the gas of stars and will thus…