相关论文: Small-Scale Mixing of the Elements
We propose a new dynamical picture of galactic stellar and gas spirals, based on hydrodynamic simulations in a `live' stellar disk. We focus especially on spiral structures excited in a isolated galactic disk without a stellar bar. Using…
The extent to which the ISM in galaxies is well mixed is not yet settled. Measured metal abundances in the diffuse neutral gas of star--forming gas--rich dwarf galaxies are deficient with respect to that of the ionized gas. The reasons, if…
We discuss the stability of galactic disks in which the energy of interstellar clouds is gained in encounters with expanding supernova remnants and lost in inelastic collisions. Energy gain and loss processes introduce a phase difference…
We numerically investigate stellar and gaseous dynamical evolution of mergers between five identical late-type disk galaxies with the special emphasis on star formation history and chemical evolution of multiple galaxy mergers. We found…
Stellar surface abundances are records of the state of the gas from which stars formed, and thus trace how individual elements have mixed into the surrounding medium following their ejection from stars. In this work, we test the common…
We suggest that the abrupt switch, from hierarchical clustering on scales larger than 0.04 pc, to binary (and occasionally higher multiple) systems on smaller scales, which Larson has deduced from his analysis of the grouping of…
ISOCAM allowed the observation of diffuse interstellar regions where the transition from atomic to molecular gas takes place. In this contribution we report on spectacular variations of small dust grains abundance in such regions observed…
It has been suggested that star-forming galaxies may host a substantial, dark reservoir of gas in the form of planetary-mass molecular clouds that are so cold that $\text{H}_{2}$ can condense. Here we investigate the process of tidal…
My thesis work aims to study the inter-relation between various physical and chemical conditions in a wide range of astrophysical environments. Our studied regions range from the super-hot regions (i.e., nebular, photon-dominated, or…
A significant fraction of clusters of galaxies are observed to have substructure, which implies that merging between clusters and subclusters is a rather common physical process of cluster formation. It still remains unclear how cluster…
Recent progress in the understanding of star formation is summarized. A consistent picture is emerging where molecular clouds form with turbulent velocity fields and clumpy substructure, imprinted already during their formation. The clouds…
Galaxy disk formation must incorporate the multiphase nature of the interstellar medium. The resulting two-phase structure is generated and maintained by gravitational instability and supernova energy input, which yield a source of…
The development of our understanding of the gaseous component of the interstellar medium is reviewed. During the 20th century our picture of diffuse material in space has grown from a simple model of isolated clouds in thermal equilibrium…
In this work, we explore the idea that substructures like stellar clusters could be formed from the tidal stream produced in galactic minor mergers. We use $N$-body and SPH simulations of satellite galaxies interacting with a larger galaxy.…
We investigate the evolution of the metallicity of the intergalactic medium (IGM) with particular emphasis on its spatial distribution. We propose that metal enrichment occurs as a two step process. First, supernova (SN) explosions eject…
According to recent models, gamma-ray bursts apparently explode in a wide variety of ambient densities ranging from ~ 10^{-3} to 30 cm^{-3}. The lowest density environments seem, at first sight, to be incompatible with bursts in or near…
Interstellar turbulence is driven over a wide range of scales by processes including spiral arm instabilities and supernovae, and it affects the rate and morphology of star formation, energy dissipation, and angular momentum transfer in…
The early evolution of dense star clusters is possibly dominated by close interactions between stars, and physical collisions between stars may occur quite frequently. Simulating a stellar collision event can be an intensive numerical task,…
Selected results from recent studies of star formation in galaxies at different stages of interaction are reviewed. Recent results from the Spitzer Space Telescope are highlighted. Ideas on how large-scale driving of star formation in…
The origin and types of spiral arms are reviewed with an emphasis on the connections between these arms and star formation. Flocculent spiral arms are most likely the result of transient instabilities in the gas that promote dense cloud…