Related papers: H2 distribution during 2-phase Molecular Cloud For…
We report JWST MIRI/MRS observations of the H2 S(1) 17.04 micron transition in two regions in the boundary of the Taurus Molecular Cloud. The two regions, denoted Edge (near the relatively sharp boundary of the 13CO J=1-0 emission) and Peak…
We have developed a complete model of the hydrogen molecule as part of the spectral simulation code Cloudy. Our goal is to apply this to spectra of high-redshift star-forming regions where H2 absorption is seen, but where few other details…
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…
We present high resolution simulations of two-fluid (ion-neutral) MHD turbulence with resolutions as large as 512^3. The simulations are supersonic and mildly sub-Alfvenic, in keeping with the conditions present in molecular clouds. Such…
We studied the statistical properties of the HI-to-H$_2$ transition observed in absorption in the local diffuse and multiphase ISM to identify the physical processes controlling the probability of occurrence of any line of sight. The…
Using the Infrared Spectrograph on board the Spitzer Space Telescope, we have detected emission in the S(0), S(1), and S(2) pure-rotational (v=0-0) transitions of molecular hydrogen (H2) towards 6 positions in two translucent high Galactic…
The formation mechanism of CO clouds observed with NANTEN2 and Mopra telescope toward the stellar cluster Westerlund 2 is studied by three-dimensional magnetohydrodynamic (MHD) simulations taking into account the interstellar cooling. These…
We suggest that molecular clouds can be formed on short time scales by compressions from large scale streams in the interstellar medium (ISM). In particular, we argue that the Taurus-Auriga complex, with filaments of 10-20 pc $\times$ 2-5…
We devise a physical model of formation and distribution of molecular gas clouds in galaxies. We use the model to predict the intensities of rotational transition lines of carbon monoxide (CO) and the molecular hydrogen (H$_{\rm 2}$)…
We extend recent numerical results (Dobbs et. al. 2006) on molecular cloud formation in spiral galaxies by including a multi-phase medium. The addition of a hot phase of gas enhances the structure in the cold gas, and significantly…
Motivated by the observed connection between molecular hydrogen (H2) and star formation, we present a method for tracking the non-equilibrium abundance and cooling processes of H2 and H2-based star formation in Smoothed Particle…
We examine observational characteristics of multi-phase turbulent flows in the diffuse interstellar medium (ISM) using a synthetic radiation field of atomic and molecular lines. We consider the multi-phase ISM which is formed by thermal…
We introduce a model for the large-scale, global 3D structure of molecular clouds. Motivated by the morphological appearance of clouds in surface density maps, we model clouds as cylinders, with the aim of backing out information about the…
We present observations of the $J$=1--0, 2--1, and 3--2 rotational transitions of N$_2$H$^+$ and N$_2$D$^+$ towards a sample of prototypical dark clouds. The data have been interpreted using non--local radiative transfer models.
Molecular clouds (MCs) are the birthplaces of new stars in galaxies. A key component of MCs are photodissociation regions (PDRs), where far-ultraviolet radiation plays a crucial role in determining the gas's physical and chemical state.…
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).…
Experimental results on the formation of molecular hydrogen on amorphous silicate surfaces are presented and analyzed using a rate equation model. The energy barriers for the relevant diffusion and desorption processes are obtained. They…
It is believed that turbulence may have a significant impact on star formation and the dynamics and evolution of the molecular clouds in which this occurs. It is also known that non-ideal magnetohydrodynamic effects influence the nature of…
Using 3D hydrodynamic calculations we simulate formation of molecular clouds in the Galaxy. The simulations take into account molecular hydrogen chemical kinetics, cooling and heating processes. Comprehensive gravitational potential…
We characterize the column density probability distributions functions (PDFs) of the atomic hydrogen gas, HI, associated with seven Galactic molecular clouds (MCs). We use 21 cm observations from the Leiden/Argentine/Bonn Galactic HI Survey…