Radiation—hydrodynamical collapse of pre-galactic clouds in the ultraviolet background

  title={Radiation—hydrodynamical collapse of pre-galactic clouds in the ultraviolet background},
  author={Tetsu Kitayama and Yukiko Tajiri and Masayuki Umemura and Hajime Susa and Satoru Ikeuchi},
  journal={Monthly Notices of the Royal Astronomical Society},
To explain the effects of the ultraviolet (UV) background radiation on the collapse of pre-galactic clouds, we implement a radiation–hydrodynamical calculation, combining one-dimensional spherical hydrodynamics with an accurate treatment of the radiative transfer of ionizing photons. Both absorption and scattering of UV photons are explicitly taken into account. It turns out that a gas cloud contracting within the dark matter potential does not settle into hydrostatic equilibrium, but undergoes… 

Figures from this paper

Criteria for the formation of Population III objects in the ultraviolet background radiation
We explore possibilities of collapse and star formation in Population III objects exposed to the external ultraviolet background (UVB) radiation. Assuming spherical symmetry, we solve
Our goal is to study the effects of the UV radiation from the first stars, quasars and hypothetical Super Heavy Dark Matter (SHDM) particle decays on the formation of primordial bound objects in the
Regulated Star Formation in Forming Disk Galaxies Exposed to the Ultraviolet Radiation Background
We perform radiation hydrodynamics simulations on the evolution of galactic gas disks irradiated by the ultraviolet radiation background. We find that gas disks with NH 1021 cm−2 that are exposed to
On the population of primordial star clusters in the presence of ultraviolet background radiation
We use the algorithm of Cole et al. to generate merger trees for the first star clusters in a � cold dark matter (� CDM) cosmology under an isotropic ultraviolet background radiation field,
How does radiative feedback from an ultraviolet background impact reionization
An ionizing UV background (UVB) inhibits gas accretion and photo-evaporates gas from the shallow potential wells of small, dwarf galaxies. During cosmological reionization, this effect can result in
Supernova Explosions in the Early Universe: Evolution of Radiative Remnants and the Halo Destruction Efficiency
We study the evolution of supernova (SN) remnants of the first stars, taking proper account of the radiative feedback of the progenitor stars on the surroundings. We carry out a series of
The depletion of gas in high-redshift dwarf galaxies from an inhomogeneous reionization
The reionization of the intergalactic medium (IGM) was likely inhomogeneous and extended. By heating the IGM and photo-evaporating gas from the outskirts of galaxies, this process can have a dramatic
Mass loss of galaxies due to an ultraviolet background
We perform cosmological hydrodynamic simulations to determine to what extent galaxies lose their gas due to photoheating from an ionizing background. We find that the characteristic mass at which
The effects of radiative transfer on the reionization of an inhomogeneous universe
Assuming simple dynamics for the growth of density fluctuations, we implement six-dimensional (6D) radiative transfer calculations to elucidate the effects of photon propagation during the
The Effects of Early Cosmic Reionization on the Substructure Problem in Galactic Halos
Recent observations of the cosmic microwave background by the Wilkinson Microwave Anisotropy Probe strongly suggest that the reionization of the universe took place quite early (z ~ 17). On the other


Formation of subgalactic clouds under ultraviolet background radiation
The effects of the ultraviolet (UV) background radiation on the formation of subgalactic clouds are studied by means of one-dimensional hydrodynamical simulations. The radiative transfer of the
During the period of reionization, the universe was filled with a cosmological background of ionizing radiation. By that time a significant fraction of the cosmic gas had already been incorporated
The Delayed Formation of Dwarf Galaxies
One of the largest uncertainties in understanding the effect of a background UV field on galaxy formation is the intensity and evolution of the radiation field with redshift. This work attempts to
Radiative shocks and hydrogen molecules in pregalactic gas - The effects of postshock radiation
Previous calculations of radiative shocks in pregalactic gas are generalized and substantially improved. The hydrodynamical conservations are solved, along with the rate equations for nonequilibrium
Hydrodynamic Simulations of Galaxy Formation. II. Photoionization and the Formation of Low Mass Galaxies
Photoionization by the high-redshift ultraviolet radiation background heats low density gas before it falls into dark matter potential wells, and it eliminates the neutral hydrogen and singly ionized
Cosmological Formation of Low-Mass Objects
We investigate the early formation of bound objects with masses comparable to the cosmological Jeans mass (10^5 solar masses). We follow the growth of isolated spherically symmetric density peaks
Destruction of Molecular Hydrogen during Cosmological Reionization
We investigate the ability of primordial gas clouds to retain molecular hydrogen (H2) during the initial phase of the reionization epoch. We find that before the Str?mgren spheres of the individual
Lyman-Alpha Clouds as a Relic of Primordial Density Fluctuations
Primordial density fluctuations are studied using a CDM model and primordial clouds some of which are expanding, driven by pressure gradients created when the medium is photionized, and some of which
The Thermal Evolution of the Postshock Layer in Pregalactic Clouds
We re-examine the thermal evolution of the postshock layer in primordial gas clouds. Comparing the time scales, we find that the evolutionary paths of postshock regions in primordial gas clouds can
Suppressing the formation of dwarf galaxies via photoionization
In hierarchical clustering theories, some sort of feedback mechanism is required to prevent most of the baryonic material collapsing into subgalactic objects at high redshifts. It is argued that a