Related papers: Exploring a dynamical path for C$_2$H$^-$ and NCO$…
Cyclopentadiene (c-C5H6) is considered a key molecule in the formation of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM). The synthesis of PAHs from simpler precursors is known as the "bottom-up" theory, which, so…
We report new results from quantum calculations of energy-transfer processes taking place in interstellar environments and involving two newly observed molecular species: C$_5$N$^-$ and C$_7$N$^-$ in collision with He atoms and the p-H$_2$…
We analyzed the NANTEN2 13CO (J=2-1 and 1-0) datasets in NGC 2024. We found that the cloud consists of two velocity components, whereas the cloud shows mostly single-peaked CO profiles. The two components are physically connected to the HII…
Expansion of wind-blown bubbles or HII regions lead to formation of shocks in the interstellar medium, which compress surrounding gas into dense layers. We made spatially and velocity-resolved observations of the RCW~120 PDR and nearby…
We report the results obtained from a multi-wavelength study of the HII region, G18.148$-$0.283, using the upgraded Giant Metre-wave Radio Telescope (uGMRT) at 1350 MHz along with other archival data. In addition to the radio continuum…
The satellite galaxy Crater II of the Milky Way is extremely cold and exceptionally diffuse. These unusual properties are challenging to understand in the standard model of cold dark matter. We investigate the formation of Crater II in…
Massive molecular clumps fragment into cores where star formation takes place, hence star-forming studies should be done at different spatial scales. Using near-IR data obtained with Gemini, data of CH3OCHO and CH3CN from the ALMA database,…
RCW120 is a Galactic HII region having a beautiful ring shape bright in infrared. Our new CO J=1-0 and J=3-2 observations performed with the NANTEN2, Mopra, and ASTE telescopes have revealed that two molecular clouds with a velocity…
We report on the first detection of C3N- and C5N- towards the cold dark core TMC-1 in the Taurus region, using the Yebes 40 m telescope. The observed C3N/C3N- and C5N/C5N- abundance ratios are 140 and 2, respectively; that is similar to…
The successive addition of H atoms to CO in the solid phase has been hitherto regarded as the primary route to form methanol in dark molecular clouds. However, recent Monte Carlo simulations of interstellar ices alternatively suggested the…
Formamide (NH$_2$CHO) has previously been detected in several star-forming regions and is thought to be a precursor for different prebiotic molecules. Its formation mechanism is still debated, however. Observations of formamide, related…
Carbon monoxide (CO) is the second most abundant molecule in the gas-phase of the interstellar medium. In dense molecular clouds, it is also present in the solid-phase as a constituent of the mixed water-dominated ices covering dust grains.…
Infrared-Dark Clouds (IRDCs) are cold, dense regions of high (optical and infrared) extinction, believed to be the birthplace of high-mass stars and stellar clusters. The physical mechanisms leading to the formation of these IRDCs are not…
%context More gas is inferred to be present in molecular cloud complexes than can be accounted for by HI and CO emission, a phenomenon known as dark neutral medium (DNM) or CO-dark gas for the molecules. %aims To see if molecular gas can be…
A new interstellar molecule, CH$_3$NCO (methyl isocyanate), has been detected using the 12 m telescope of the Arizona Radio Observatory (ARO). CH$_3$NCO was identified in spectra covering 48 GHz (68-116 GHz) in the 3 mm segment of a…
A basic model for the formation of non-equilibrium rotational energy distributions is described for reactive, homo-polar diatomic molecules and ions in the interstellar medium. Kinetic models were constructed to calculate the rotational…
Carbon monoxide (CO) emission is a widely used tracer of molecular hydrogen (H$_2$) in the interstellar medium (ISM), owing to its abundance, low excitation energy, and ease of detection in cold molecular environments, in contrast to…
Magnetic fields play a role in the dynamics of many astrophysical processes, but they are hard to detect. In a partially ionized plasma, a magnetic field works directly on the ionized medium but not on the neutral medium, which gives rise…
The end-to-end dynamics of the smallest energized Criegee intermediate, H$_2$COO, was characterized for vibrational excitation close to and a few kcal/mol above the barrier for hydrogen transfer. From an aggregate of at least 5 $\mu$s of…
We investigate the star formation processes operating in a mid-infrared bubble N49 site, which harbors an O-type star in its interior, an ultracompact HII region, and a 6.7 GHz methanol maser at its edges. The 13CO line data reveal two…