Related papers: Modelling CO formation in the turbulent interstell…
We report a survey of molecular emission from cometary volatiles using the James Webb Space Telescope (JWST) toward interstellar object 3I/ATLAS carried out on UT 2025 December 22 and 23 at a heliocentric distance ($r_H$) of $2.37-2.41$ au.…
We discuss HD and MHD compressible turbulence as a cloud-forming and cloud-structuring mechanism in the ISM. Results from a numerical model of the turbulent ISM at large scales suggest that the phase-like appearance of the medium, the…
Emission from carbon monoxide (CO) is ubiquitously used as a tracer of dense star forming molecular clouds. There is, however, growing evidence that a significant fraction of CO emission originates from diffuse molecular gas. Quantifying…
CO is the most widely used gas tracer of protoplanetary disks. Its abundance is usually assumed to be an interstellar ratio throughout the warm molecular layer of the disk. But recent observations of low CO gas abundance in many…
This paper presents maps of the J=2-1 transition of CO toward the Draco Nebula Intermediate Velocity Cloud (IVC). The maps cover 8500 square arcmin with a velocity resolution of 0.33 km~s$^{-1}$ and angular resolution of 38", or 0.11 pc at…
Condensation of H 2 in the interstellar medium (ISM) has long been seen as a possibility, either by deposition on dust grains or thanks to a phase transition combined with self-gravity. H 2 condensation might explain the observed low…
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…
{It is necessary to understand the dynamics of the atomic gas to use complex modeling and to carry out detailed comparisons between theoretical models and observations.}{In a companion paper, we present high resolution bidimensional…
We have mapped cold atomic gas in 21cm line HI self-absorption (HISA) at arcminute resolution over more than 90% of the Milky Way's disk. To probe the formation of H2 clouds, we have compared our HISA distribution with CO J=1-0 line…
The winds and radiation from massive stars clear out large cavities in the interstellar medium. These bubbles, as they have been called, impact their surrounding molecular clouds and may influence the formation of stars therein. Here we…
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…
We explore the origin of fast molecular outflows that have been observed in Active Galactic Nuclei (AGN). Previous numerical studies have shown that it is difficult to create such an outflow by accelerating existing molecular clouds in the…
We present numerical computations and analysis of atomic to molecular (HI-to-H$_2$) transitions in cool ($\sim$100 K) low-metallicity dust-free (primordial) gas, in which molecule formation occurs via cosmic-ray driven negative ion…
12CO 1-0,2-1,4-3,7-6, and 13CO 1-0, 2-1, and 3-2 line was mapped with angular resolutions of 13" - 22" toward the nuclear region of starburst galaxy M82. The difference of lobe spacings in submillimeter (~15") and millimeter (~26") lines…
We measure the parsec-scale relationship between integrated CO intensity (I_CO) and visual extinction (A_V) in 24 local molecular clouds using maps of CO emission and dust optical depth from Planck. This relationship informs our…
Formation of interstellar clouds as a consequence of thermal instability is studied using two-dimensional two-fluid magnetohydrodynamic simulations. We consider the situation of converging, supersonic flows of warm neutral medium in the…
[Abridged] Observations of protoplanetary disks suggest that they are depleted in gas-phase CO. It has been posed that gas-phase CO is chemically consumed and converted into less volatile species through gas-grain processes. Observations of…
[Abridged] Do some environments favor efficient conversion of molecular gas into stars? To answer this, we need to be able to estimate the H2 mass. Traditionally, this is done using CO and a few assumptions but the Herschel observations in…
We investigate the interplay between the ionization radiation from massive stars and the turbulence inside the surrounding molecular gas thanks to 3D numerical simulations. We used the 3D hydrodynamical code HERACLES to model an initial…
We present first results of the evolution of cold cosmic gas obtained through a set of state-of-the-art numerical simulations (ColdSIM). We model time-dependent atomic and molecular non-equilibrium chemistry coupled to HI and H$_2$…