相关论文: Dwarf Galaxy Formation Was Suppressed By Cosmic Re…
We compare the properties of dwarf galaxies in the Local Group with the simulated galaxies formed before reionization in a cosmological simulation of unprecedented spatial and mass resolution,including radiative feedback effects. We find…
We study how star formation is regulated in low-mass field dwarf galaxies ($10^5 \leq M_{\star} \leq 10^6 \, \text{M}_{\odot}$), using cosmological high-resolution ($3 \, \text{pc}$) hydrodynamical simulations. Cosmic reionization quenches…
One of the milestones in the cosmic history is the formation of the first luminous objects and Hydrogen reionization. The standard theory of cosmic structure formation predicts that the first generation of stars were born about a few…
It has been argued that a UV photoionizing background radiation field suppresses the formation of dwarf galaxies, and may even inhibit the formation of larger galaxies. In order to test this, we present gas-dynamical simulations of the…
The Universe's dark ages end with the formation of the first generation of galaxies. These objects start emitting ultraviolet radiation that carves out ionized regions around them. After a sufficient number of ionizing sources have formed,…
The WMAP satellite has measured a large optical depth to electron scattering after cosmological recombination of 0.17+-0.04, implying significant reionization of the primordial gas only ~200 million years after the big bang. However, the…
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 analysis employs a combination of high-precision photometry…
The Local Group hosts a number of star-forming dwarf galaxies that show evidence of periods of little to no star formation. We use a suite of cosmological simulations to study how star formation is reignited in such galaxies. We focus on…
The history of the transition from a neutral intergalactic medium (IGM) to one that is almost fully ionized can reveal the character of cosmological ionizing sources and set important constraints on the stellar birthrate at high redshifts.…
Star-forming dwarf galaxies in the local Universe, especially extremely metal-poor ones, can be considered analogous to early galaxies of the Epoch of Reionization (z >= 6). Currently available telescopes cannot adequately detect and…
Star-forming galaxies in the early universe provide us with perhaps the most natural way of explaining the reionization of the universe. Current observational results are sufficiently comprehensive, as to allow us to approximately calculate…
The contribution of stars in galaxies to cosmic reionisation depends on the star formation history in the Universe, the abundance of galaxies during reionisation, the escape fraction of ionising photons and the clumping factor of the…
In cosmological models favored by current observations, the first astrophysical objects formed in dark matter halos at redshifts starting at z>20, and their properties were determined by primordial H_2 molecular chemistry. These…
The ionization fraction of cosmic hydrogen, left over from the big bang, provides crucial fossil evidence for when the first stars and quasar black holes formed in the infant universe. Spectra of the two most distant quasars known show…
We study structure formation in cosmological void regions using high-resolution hydrodynamical simulations. Despite being significantly underdense, voids are populated abundantly with small dark matter halos which should appear as dwarf…
The first galaxies to appear in the universe at redshifts z>20 created ionized bubbles in the intergalactic medium of neutral hydrogen left over from the Big-Bang. It is thought that the ionized bubbles grew with time, surrounded clusters…
Recent observations have found that many $z\sim 6$ quasar fields lack galaxies. This unexpected lack of galaxies may potentially be explained by quasar radiation feedback. In this paper I present a suite of 3D radiative transfer…
We use high-resolution simulations of cosmological volumes to model galaxy formation at high-redshift, with the goal of studying the photon budget for reionization. We demonstrate that galaxy formation models that include a strong,…
While most of the inter-galactic medium (IGM) today is permeated by ionized hydrogen, it was largely filled with neutral hydrogen for the first 700 million years after the Big Bang. The process that ionized the IGM (cosmic reionization) is…
Over the past two decades, an avalanche of data from multiwavelength imaging and spectroscopic surveys has revolutionized our view of galaxy formation and evolution. Here we review the range of complementary techniques and theoretical tools…