Detection of D 2 H + in the Dense Interstellar Medium

Detection of H 3 1 in the Diffuse Interstellar Medium

The molecular ion H3 1 is considered the cornerstone of interstellar chemistry because it initiates the reactions responsible for the production of many larger molecules. Recently discovered in dense molecular clouds, H3 1 has now been observed in the diffuse interstellar medium toward Cygnus OB2 No. 12. Analysis of H3 1 chemistry suggests that the high H3 1 column density (3.8 3 10 per square ...

H 2 formation and excitation in the diffuse interstellar medium

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 photon-illuminated gas. The data constrain well the n R product between gas density and H2 formation rate on dust grains: n R = 1 to 2.2 10s. For each line of sight the mean...

Formation of H 3− by radiative association of H 2 and H− in the interstellar medium

The Energetic Environment and the Dense Interstellar Medium in Ulirgs

We fit the near-infrared to radio spectral energy distributions of a sample of 30 luminous and ultra-luminous infrared galaxies with models that include both starburst and AGN components. The aim of the work was to determine important physical parameters for this kind of objects such as the optical depth towards the luminosity source, the star formation rate, the star formation efficiency and t...

The effect of grain size distribution on H 2 formation rate in the interstellar medium

The formation of molecular hydrogen in the interstellar medium takes place on the surfaces of dust grains. Hydrogen molecules play a role in gasphase reactions that produce other molecules, some of which serve as coolants during gravitational collapse and star formation. Thus, the evaluation of the production rate of hydrogen molecules and its dependence on the physical conditions in the cloud ...