相关论文: Molecular hydrogen formation on dust grains in the…
We study the impact of molecular (${\rm H_2}$) and atomic (HI) hydrogen cooling on the galaxy formation threshold. We calculate the fraction of dark matter (DM) halos that exceeds a critical mass required for star formation,…
To investigate how the abundance of N2H+ varies as massive clumps evolve, here we present a multi-wavelength study toward six molecular clouds. All of these clouds contain several massive clumps in different evolutionary stages of star…
Context. Interstellar dust particles, which represent 1% of the total mass, are recognized to be very powerful interstellar catalysts in star-forming regions. The presence of dust can have a strong impact on the chemical composition of…
H2 formation remains a major issue for the understanding of interstellar physics. We investigate H2 formation in the interstellar medium at the light of the most recent experimental and theoretical data. We implemented detailed H2 formation…
Recent simulation studies suggest that the compaction of star-forming galaxies (SFGs) at high redshift might be a critical process, during which the central bulge is being rapidly built, followed by quenching of the star formation. To…
We investigate the formation of molecular hydrogen (H_2) in a primordial H+He gas cloud irradiated by a power-law UV flux. We find that at high densities (>1 cm^{-3}) and low temperatures (<10^4 K), the background radiation enhances the…
The large amounts of dust detected in sub-millimeter galaxies and quasars at high redshift pose a challenge to galaxy formation models and theories of cosmic dust formation. At z > 6 only stars of relatively high mass (> 3 Msun) are…
We use far-UV absorption spectra obtained with FUSE towards three late B stars to study the formation and excitation of H2 in the diffuse ISM. The data interpretation relies on a model of the chemical and thermal balance in…
Stars in galaxies form in giant molecular clouds that coalesce when the atomic hydrogen is converted into molecules. There are currently two dominant models for what property of the galactic disk determines its molecular fraction: either…
We present a detailed description of a phenomenological H2 formation model and local star formation prescription based on the density of molecular (rather than total) gas. Such approach allows us to avoid the arbitrary density and…
The faint CO gases in debris disks are easily dissolved into C by UV irradiation, while CO can be reformed via reactions with hydrogen. The abundance ratio of C/CO could thus be a probe of the amount of hydrogen in the debris disks. We…
Modelling the molecular gas that is routinely detected through CO observations of high-redshift galaxies constitutes a major challenge for ab initio simulations of galaxy formation. We carry out a suite of cosmological hydrodynamic…
We show that gaseous \HI disks of primordial composition irradiated by an external radiation field can develop a multiphase medium with temperatures between 10^2 and 10^4 K due to the formation of molecular hydrogen. For a given \HI column…
We investigate the sources and amount of dust in early galaxies. We discuss dust nucleation in stellar atmospheres using published extended atmosphere models, stellar evolution tracks and nucleation conditions and conclude that the (TPAGB)…
Molecular hydrogen (H2) is the primary component of the reservoirs of cold, dense gas that fuel star formation in our galaxy. While the H2 abundance is ultimately regulated by physical processes operating on small scales in the interstellar…
Methods: The microscopic equations of H2-formation and protonation are integrated numerically over time in such a manner that the overall structures evolve self-consistently under benign conditions. Results: The equilibrium H2 formation…
An analysis of the kinetics of H2 formation on interstellar dust grains is presented using rate equations. It is shown that semi-empirical expressions that appeared in the literature represent two different physical regimes. In particular,…
Numerical simulations suggest that the first galaxies are formed in protogalactic halos with virial temperatures >= 10^4 K. It is likely that such halos are polluted with trace amounts of metals produced by the first generation of stars.…
We aim to measure the average dust and molecular gas content of massive star-forming galaxies ($\rm > 3 \times 10^{10}\,M_\odot$) up to z=4 in the COSMOS field to determine if the intense star formation observed at high redshift is induced…
The initial stage of star formation is a complex area study because of its high density and low temperature. Under such conditions, many molecules become depleted from the gas phase by freezing out onto dust grains. However, the deuterated…