Related papers: Interstellar Hydrocarbons: Degradation Chemistry i…
During the evolution of diffuse clouds to molecular clouds, gas-phase molecules freeze out on surfaces of small dust particles to form ices. On dust surfaces, water is the main constituent of the icy mantle in which a complex chemistry is…
Carbon monoxide (CO) is a poor tracer of H$_{2}$ in the diffuse interstellar medium (ISM), where most of the carbon is not incorporated into CO molecules unlike the situation at higher extinctions. We present a novel, indirect method to…
We present column density measurements of the HD molecule in the interstellar gas toward 17 Galactic stars. The values for the seven most heavily reddened sightlines, with E(B-V) = 0.38-0.72, are derived from observations with the Far…
Galactic Bulge Planetary Nebulae show evidence of mixed chemistry with emission from both silicate dust and PAHs. This mixed chemistry is unlikely to be related to carbon dredge up, as third dredge-up is not expected to occur in the low…
The intermittent dissipation of interstellar turbulence is an important energy source in the diffuse ISM. Though on average smaller than the heating rates due to cosmic rays and the photoelectric effect on dust grains, the turbulent cascade…
We present experimental results obtained from photoionization and photodissociation processes of abundant interstellar CH$_3$-X type organic molecules like methanol (CH$_3$OH), methylamine (CH$_3$NH$_2$) and acetonitrile (CH$_3$CN) as…
Our understanding of how molecular clouds form in the interstellar medium (ISM) would be greatly helped if we had a reliable observational tracer of the gas flows responsible for forming the clouds. Fine structure emission from singly…
We decomposed the molecular gas in the spiral galaxy NGC 628 (M74) into multi-scale hub-filament structures using the CO (2-1) line by the dendrogram algorithm. All leaf structures as potential hubs were classified into three categories,…
Intermediate-velocity clouds (IVCs) are HI halo clouds that are likely related to a Galactic fountain process. In-falling IVCs are candidates for the re-accretion of matter onto the Milky Way. We study the evolution of IVCs at the disk-halo…
Polycyclic aromatic hydrocarbons (PAHs) and fullerenes play a major role in the physics and chemistry of the interstellar medium. Based on a number of recent experimental and theoretical investigations we developed a model in which PAHs are…
Understanding the molecular content of galaxies is a critical problem in star formation and galactic evolution. Here we present a new method, based on a Stromgren-type analysis, to calculate the amount of HI that surrounds a molecular cloud…
Gas-phase processes were long thought to be the key formation mechanisms for complex organic molecules in star-forming regions. However, recent experimental and theoretical evidence has cast doubt on the efficiency of such processes.…
As a complement to the HyGAL Stratospheric Observatory for Infrared Astronomy Legacy Program, we report the results of a ground-based absorption line survey of simple molecules in diffuse and translucent Galactic clouds. Using the Institut…
We investigate the chemical evolution of a collapsing core that starts from a hydrostatic core and finally form a low-mass protostar. New multiphase gas-grain models that include bulk diffusion and photon penetration are simulated by the…
We report the results of initial FUSE observations of molecular hydrogen (H2) in translucent clouds. These clouds have greater optical depth than any of the diffuse clouds previously observed for far-UV H2 absorption, and provide new…
Young massive stars produce Far-UV photons which dissociate the molecular gas on the surfaces of their parent molecular clouds. Of the many dissociation products which result from this ``back-reaction'', atomic hydrogen \HI is one of the…
We study ten molecular transitions obtained from an unbiased 3 mm molecular line survey using the IRAM 30 m telescope toward 409 compact dust clumps identified by the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) to understand…
It is a fact that interstellar formation processes are thermodynamically affected. Based on this, the seven heterocycles; imidazole, pyridine, pyrimidine, pyrrole, quinoline, isoquinoline and furan that have been searched for from different…
We derived the dust-to-HI ratio of the intermediate-velocity clouds (IVCs), the high-velocity clouds (HVCs), and the local HI gas, by carrying out a multiple-regression analysis of the 21cm HI emission combined with the sub-mm dust optical…
We have combined infrared data with HI, H2 and HII surveys in order to spatially decompose the observed dust emission into components associated with different phases of the gas. An inversion technique is applied. For the decomposition, we…