Related papers: Time-dependent models of dense PDRs with complex m…
We use 3D-PDR, a three-dimensional astrochemistry code for modeling photodissociation regions (PDRs), to post-process hydrodynamic simulations of turbulent, star-forming clouds. We focus on the transition from atomic to molecular gas, with…
The physical and chemical conditions in photodissociation regions (PDRs) are largely determined by the influence of far ultraviolet radiation. Far-UV photons can efficiently dissociate molecular hydrogen, a process that must be balanced at…
We aim to investigate the chemistry of internal photon-dominated regions surrounding deeply embedded hypercompact and ultracompact HII regions. We search for specific tracers of this evolutionary stage of massive star formation that can be…
We present a study of small carbon chains and rings in Photon Dominated Regions (PDRs) performed at millimetre wavelengths. Our sample consists of the Horsehead nebula (B33), the rho,Oph L1688 cloud interface, and the cometary-shaped cloud…
We study the chemistry of small hydrocarbons in the photon-dominated regions (PDRs) associated with the ultra-compact HII region Mon R2. Our goal is to determine the variations of the abundance of small hydrocarbons in a high-UV irradiated…
When studying the chemistry of PDRs, time dependence becomes important as visual extinction increases, since certain chemical timescales are comparable to the cloud lifetime. Dust temperature is also a key factor, since it significantly…
We present a comparison between independent computer codes, modeling the physics and chemistry of interstellar photon dominated regions (PDRs). Our goal was to understand the mutual differences in the PDR codes and their effects on the…
The interstellar medium is known to be chemically complex. Organic molecules with up to 11 atoms have been detected in the interstellar medium, and are believed to be formed on the ices around dust grains. The ices can be released into the…
We present high-resolution spectroscopy and images of a photodissociation region (PDR) in M16 obtained during commissioning of NIRSPEC on the Keck II telescope. PDRs play a significant role in regulating star formation, and M16 offers the…
Molecular line observations may serve as diagnostics of the degree to which the number density of cosmic ray protons, having energies of 10s to 100s of MeVs each, is enhanced in starburst galaxies and galaxies with active nuclei. Results,…
We study the spatial distribution and chemistry of small hydrocarbons in the Orion Bar PDR. We used the IRAM-30m telescope to carry out a millimetre line survey towards the Orion Bar edge, complemented with ~2'x2' maps of the C2H and c-C3H2…
We present maps at high spatial and spectral resolution in emission lines of C2H, c-C3H2, C4H, 12CO and C18O of the edge of the Horsehead nebula obtained with the Plateau de Bure Interferometer (PdBI). The edge of the Horsehead nebula is a…
We present a study of emission lines of small hydrocarbons C$_2$H and $c$-C$_3$H$_2$, and COMs precursors H$_2$CO and CH$_3$OH in order to better understand the possible chemical link between the molecular abundances and UV radiation field…
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…
Photon-dominated regions (PDRs) are powerful molecular line emitters in external galaxies. They are expected in galaxies with high rates of massive star formation due to either starburst (SB) events or starburst coupled with active galactic…
Modern observations of the interstellar medium (ISM) in galaxies detect a variety of atomic and molecular species. The goal is to connect these observations to the astrochemical properties of the ISM. 3D hydro-chemical simulations attempt…
Photodissociation regions (PDRs) contain a large fraction of all of the interstellar matter in galaxies. Classical examples include the boundaries between ionized regions and molecular clouds in regions of massive star formation, marking…
We consider the evolution of an isentropic thermal instability in the atomic zone of a photodissociation region (PDR). In this zone, gas heating and cooling are associated mainly with photoelectric emission from dust grains and…
Numerical models of Photodissociation Regions (PDRs) are an essential tool to quantitatively understand observations of massive star forming regions through simulations. Few mature PDR models are available and the Cologne KOSMA-$\tau$ PDR…
The radiation from stars and active galactic nuclei (AGN) creates photodissociation regions (PDRs) and X-ray dominated regions (XDRs), where the chemistry or heating are dominated by far-ultraviolet (FUV) radiation or X-ray radiation,…