Low velocity shocks: signatures of turbulent dissipation in diffuse irradiated gas

Abstract

We examine the chemical and emission properties of mildly irradiated (G0=1) magnetised shocks in diffuse media (nH=10^2 to 10^4 /cm3) at low to moderate velocities (from 3 to 40 km/s). Results: The formation of some molecules relies on endoergic reactions. In J-shocks, their abundances are enhanced by several orders of magnitude for shock velocities as low as 7 km/s. Otherwise most chemical properties of J-type shocks vary over less than an order of magnitude between velocities from about 7 to about 30 km/s, where H2 dissociation sets in. C-type shocks display a more gradual molecular enhancement as the shock velocity increases. We quantify the energy flux budget (fluxes of kinetic, radiated and magnetic energies) with emphasis on the main cooling lines of the cold interstellar medium. Their sensitivity to shock velocity is such that it allows observations to constrain statistical distributions of shock velocities. We fit various probability distribution functions (PDFs) of shock velocities to spectroscopic observations of the galaxy-wide shock in Stephan's Quintet (SQ) and of a Galactic line of sight sampling diffuse molecular gas in Chamaeleon. In both cases, low velocities bear the greatest statistical weight and the PDF is consistent with a bimodal distribution. In the very low velocity shocks (below 5 km/s), dissipation is due to ion-neutral friction which powers H2 low energy transitions and atomic lines. In moderate velocity shocks (20 km/s and above), the dissipation is due to viscous heating and accounts for most of the molecular emission. In our interpretation a significant fraction of the gas on the line of sight is shocked (from 4% to 66%). For example, C+ emission may trace shocks in UV irradiated gas where C+ is the dominant carbon species.

arXiv commentIn press, version prior to language edition, 15 pages, 19 figures

References in corpus (25)

• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• Structure of Stationary Photodissociation Fronts
• A model for atomic and molecular interstellar gas: The Meudon PDR code
• An Origin of Supersonic Motions in Interstellar Clouds
• Thermal condensation in a turbulent atomic hydrogen flow
• On the Relationship Between Molecular Hydrogen and Carbon Monoxide Abundances in Molecular Clouds
• Molecular Cloud Formation Behind Shock Waves
• Powerful High Velocity-Dispersion Molecular Hydrogen Associated with an Intergalactic Shock Wave in Stephan's Quintet
• Models of turbulent dissipation regions in the diffuse interstellar medium
• The chemistry of vibrationally excited H2 in the interstellar medium
• H2 formation and excitation in the diffuse interstellar medium
• H2 formation and excitation in the Stephan's Quintet galaxy-wide collision
• Comparative study of CH+ and SH+ absorption lines observed towards distant star-forming regions
• Powerful H${}_2$ Line-cooling in Stephan's Quintet : I - Mapping the Significant Cooling Pathways in Group-wide Shocks
• Turbulent molecular gas and star formation in the shocked intergalactic medium of Stephan's Quintet
• Temporal evolution of magnetic molecular shocks I. Moving grid simulations
• Spitzer IRS Detection of Molecular Hydrogen Rotational Emission Towards Translucent Clouds
• Strong CH+ J=1-0 emission and absorption in DR21
• Dust grains and the structure of steady C-type magnetohydrodynamic shock waves in molecular clouds
• Temporal evolution of magnetic molecular shocks II. Analytics of the steady state and semi-analytical construction of intermediate ages
• Observations and modeling of the dust emission from the H2-bright galaxy-wide shock in Stephan's Quintet
• Variations in H2O+/H2O ratios toward massive star-forming regions
• Modeling of diffuse molecular gas applied to HD 102065 observations
• Far-infrared emission from intergalactic medium in Stephan's Quintet revealed by AKARI
• Fluctuations of statistics among subregions of a turbulence velocity field

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