Related papers: H2 Formation in Low Metallicity Galaxies
We study the formation of molecular hydrogen on dust grain surfaces and apply our results to the high redshift universe. We find that a range of physical parameters, in particular dust temperature and gas temperature, but not so much dust…
We have developed a model for molecular hydrogen formation under astrophysically relevant conditions. This model takes fully into account the presence of both physisorbed and chemisorbed sites on the surface, allows quantum mechanical…
The metal deficient starburst galaxy IZw18 has been observed with FUSE in a search for H2 molecules. The spectrum obtained with an aperture covering the full galaxy shows no absorption lines of diffuse H2 at the radial velocity of the…
The study of the formation of molecular hydrogen on low temperature surfaces is of interest both because it allows to explore elementary steps in the heterogeneous catalysis of a simple molecule and because of the applications in…
The James Webb Space Telescope (JWST) has revealed unexpectedly rapid galaxy assembly in the early universe, in tension with models of star and galaxy formation. In the gas conditions typical of early galaxies, particularly their low…
Abridged. Low-metallicity star-forming dwarf galaxies are prime targets to understand the chemical enrichment of the interstellar medium. The HI region provides important constraints on the dispersal and mixing of heavy elements released by…
We have investigated the time scale for formation of molecular clouds by examining the conversion of HI to H2 using a time-dependent model. H2 formation on dust grains and cosmic ray and photo destruction are included in one-dimensional…
Physical conditions within DLAs can reveal the star formation history, determine the chemical composition of the associated ISM, and hence document the first steps in the formation of present day galaxies. Here we present calculations that…
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,…
We use a sample of 47 homogeneous and high sensitivity CO images taken from the Nobeyama and BIMA surveys to demonstrate that, contrary to common belief, a significant number (~40%) of HI-deficient nearby spiral galaxies are also depleted…
Molecular hydrogen is the most abundant molecule in the universe. It is the first one to form and survive photo-dissociation in tenuous environments. Its formation involves catalytic reactions on the surface of interstellar grains. The…
We present Giant Metrewave Radio Telescope (GMRT) observations for three (viz., DDO 68, SDSS J2104-0035 and UGC 772) of the six most metal-deficient actively star-forming galaxies known. Although there is a debate as to whether these…
We use a suite of hydrodynamics simulations of the interstellar medium (ISM) within a galactic disk, which include radiative transfer, a non-equilibrium model of molecular hydrogen, and a realistic model for star formation and feedback, to…
Carbon monoxide (CO) is the primary tracer for interstellar clouds where stars form, yet CO has never been detected in galaxies with an Oxygen abundance relative to Hydrogen less than 20% of solar, even though such low metallicity galaxies…
The extent to which star formation varies in galaxies with low masses, low metallicities, and high star formation rate surface densities is not well-constrained. To gain insight into star formation under these physical conditions, this…
Lyman- and Werner-band absorption of molecular hydrogen (H$_2$) is detected in $\sim$50% of low redshift ($z<1$) DLAs/sub-DLAs with $N$(H$_2$) > 10$^{14.4}$ cm$^{-2}$. However the true origin(s) of the H$_2$ bearing gas remain elusive. Here…
We study the evolution of molecular hydrogen on the grain surfaces and in the gas phase using both the rate equation (which tracks the average number of molecules) and the master equation (which tracks the expectation values of molecules).…
We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the…
Experimental results on the formation of molecular hydrogen on amorphous silicate surfaces are presented for the first time and analyzed using a rate equation model. The energy barriers for the relevant diffusion and desorption processes…
We describe a phenomenological model for molecular hydrogen formation suited for applications in galaxy formation simulations, which includes on-equilibrium formation of molecular hydrogen on dust and approximate treatment of both its…