相关论文: Radiative feedback from ionized gas
[Abridged] Observations of protoplanetary disks suggest that they are depleted in gas-phase CO. It has been posed that gas-phase CO is chemically consumed and converted into less volatile species through gas-grain processes. Observations of…
We model the combined effects of photoionization and momentum--driven winds from O--stars on molecular clouds spanning a parameter space of initial conditions. The dynamical effects of the winds are very modest. However, in the lower--mass…
The build-up of galaxies is regulated by a complex interplay between gravitational collapse, galaxy merging and feedback related to AGN and star formation. The energy released by these processes has to dissipate for gas to cool, condense,…
We develop the theory of radiative association of an atom and a diatomic molecule within a close-coupling framework. We apply it to the formation of H$_3^-$ after the low energy collision (below 0.5 eV) of H$_2$ with H$^-$. Using recently…
We study the formation and evolution of HII regions around the first stars formed at z=10-30. We use a one-dimensional Lagrangian hydrodynamics code which self-consistently incorporates radiative transfer and non-equilibrium primordial gas…
Experiments are conducted to investigate the role of the avoided crossing seam in the photodissociation of H$_3^+$. Three-dimensional imaging of dissociation products is used to determine the kinetic energy release and branching ratio among…
Observations show that star formation is an inefficient and slow process. This result can be attributed to the injection of energy and momentum by stars that prevents free-fall collapse of molecular clouds. The mechanism of this stellar…
ISO has provided us with a new perspective on gas temperatures in photodissociation regions through measurements of line emission from rotationally-excited levels of the H_2 molecule. The H_2 rotational level populations provide a thermal…
The formation of stars from gas drives the evolution of galaxies. Yet, it remains one of the hardest processes to understand when trying to connect observations of stellar and galaxy populations to models of large scale structure formation.…
We investigate star formation occurring in idealised giant molecular clouds, comparing structures that evolve in isolation versus those undergoing a collision. Two different collision speeds are investigated and the impact of photoionising…
Feedback from photoionisation may dominate on parsec scales in massive star-forming regions. Such feedback may inhibit or enhance the star formation efficiency and sustain or even drive turbulence in the parent molecular cloud.…
We present three-dimensional radiation-hydrodynamical simulations of the impact of stellar winds, photoelectric heating, photodissociating and photoionising radiation, and supernovae on the chemical composition and star formation in a…
Joint electron-ion energy spectra for the dissociative ionization of a model H$_2^+$ in few-cycle, infrared laser pulses are calculated via the numerical ab initio solution of the time-dependent Schr\"odinger equation. A strong,…
The presence of ultra-high energy cosmic rays in the universe in the pre-ionization epoch enhances significantly H$_2$ kinetics in virialized halos. It results in more efficient radiative cooling and decreases the lower mass limit of the…
We show that the cosmic star formation rate per comoving volume should exhibit a distinct drop around the reionization redshift, when the HII regions in the intergalactic medium around individual ionizing sources first overlapped. The drop…
The role of HD cooling in the formation of primordial objects is examined by means of a great number of 1-D models of the collapse of halos, exploring a wide range of masses and virialization redshifts. We find that HD has very little…
We present numerical methods for including stellar feedback in galaxy-scale simulations. We include heating by SNe (I & II), gas recycling and shock-heating from O-star & AGB winds, HII photoionization, and radiation pressure from stellar…
We examine the star formation history and stellar feedback effects of dwarf galaxies under the influence of extragalactic ultraviolet radiation. We consider the dynamical evolution of gas in dwarf galaxies using a one-dimensional,…
A possible formation mechanism of hydrogen molecules on a galactic scale is examined. We are interested especially in the role of hydrogen molecules for formation and evolution of primordial galaxies. Then, formation process of hydrogen…
We present a new set of analytic models for the expansion of HII regions powered by UV photoionisation from massive stars and compare them to a new suite of radiative magnetohydrodynamic simulations of turbulent, self-gravitating molecular…