Interaction of interstellar shocks with dense obstacles: Formation of “bullets”

2008 ◽  
pp. 141-144
Author(s):  
V. V. Gvaramadze
Keyword(s):  
Interstellar Shocks

scholarly journals Interaction of Interstellar Shocks with Dense Obstacles: Formation of “Bullets”

1997 ◽  
Vol 166 ◽  
pp. 141-144
Author(s):  
V.V. Gvaramadze
Keyword(s):  
Shock Waves ◽  
Supernova Remnants ◽  
Cumulative Effect ◽  
Significant Part ◽  
Star Forming ◽  
Star Forming Regions ◽  
Cone Axis ◽  
Conical Shock ◽  
Interstellar Shocks ◽  
Converging Flow

AbstractThe so-called cumulative effect take place in converging conical shock waves arising behind dense obstacles overtaken by incident interstellar shock. A significant part of energy of converging flow of matter swept-up by a radiative conical shock can be transferred to a dense jet-like ejection (“bullet”) directed along the cone axis. Possible applications of this effect for star-forming regions (e.g., OMC-1) and supernova remnants (e.g., Vela SNR) are discussed.

scholarly journals Non thermal sputtering of grains and production of SiO in interstellar shocks

1997 ◽  
Vol 178 ◽  
pp. 113-128 ◽  
Author(s):  
Guillaume Pineau Des Forêts ◽  
David Flower
Keyword(s):  
Gas Phase ◽  
Satisfactory Agreement ◽  
Shock Model ◽  
Dense Gas ◽  
Heavy Particles ◽  
Molecular Outflows ◽  
Dark Clouds ◽  
Interstellar Grains ◽  
Upper Limits ◽  
Interstellar Shocks

We present recent results for the yields of Si and O, produced in the sputtering of SiO2 by ions of different masses, and show the importance of sputtering by heavy particles at low streaming velocities. These data are incorporated in a C-shock model to study the erosion of interstellar grains and the release of silicon through non-thermal sputtering within the shock. Once in the gas phase, the atomic silicon reacts with O2 and is rapidly transformed into SiO. The column densities of SiO thus calculated are compared with the observations of molecular outflows with a satisfactory agreement. In the postshock gas, SiO disappears from the gas phase through the reaction SiO(OH,H)SiO2 and SiO2 remains, unseen, in the cold dense gas. This could explain the extremely low upper limits of SiO deduced from observations of dark clouds.

The importance of chemical data for the study of interstellar shocks

1995 ◽  
Vol 233 (1-2) ◽  
pp. 125-137
Author(s):  
Evelyne Roueff ◽  
Guillaume Pineau Des For�ts ◽  
David R. Flower
Keyword(s):  
Chemical Data ◽  
Interstellar Shocks

scholarly journals OH cooling of interstellar shocks and masers

1982 ◽  
Vol 200 (1) ◽  
pp. 55P-59P ◽  
Author(s):  
D. R. Flower ◽  
S. Guilloteau ◽  
T. W. Hartquist
Keyword(s):  
Interstellar Shocks

Interstellar shocks and elemental depletions

1982 ◽  
Vol 85 (1-2) ◽  
pp. 221-230 ◽  
Author(s):  
W. W. Duley
Keyword(s):  
Interstellar Shocks

The Importance of Chemical Data for the Study of Interstellar Shocks

1995 ◽  
pp. 125-137
Author(s):  
Evelyne Roueff ◽  
Guillaume Pineau des Forêts ◽  
David R. Flower
Keyword(s):  
Chemical Data ◽  
Interstellar Shocks

Formation of molecular CH/+/ in interstellar shocks

1978 ◽  
Vol 222 ◽  
pp. L141 ◽  
Author(s):  
M. Elitzur ◽  
W. D. Watson
Keyword(s):  
Interstellar Shocks

scholarly journals Models of irradiated molecular shocks

2019 ◽  
Vol 622 ◽  
pp. A100 ◽  
Author(s):  
B. Godard ◽  
G. Pineau des Forêts ◽  
P. Lesaffre ◽  
A. Lehmann ◽  
A. Gusdorf ◽  
...  
Keyword(s):  
Radiation Field ◽  
Uv Radiation ◽  
Mechanical Energy ◽  
Line Emission ◽  
Low Velocity ◽  
Integration Algorithm ◽  
Physical Conditions ◽  
Wide Range ◽  
Interstellar Shocks ◽  
Molecular Lines

Context. The recent discovery of excited molecules in starburst galaxies observed with ALMA and the Herschel space telescope has highlighted the necessity to understand the relative contributions of radiative and mechanical energies in the formation of molecular lines and explore the conundrum of turbulent gas bred in the wake of galactic outflows. Aims. The goal of the paper is to present a detailed study of the propagation of low velocity (5–25 km s−1) stationary molecular shocks in environments illuminated by an external ultraviolet (UV) radiation field. In particular, we intend to show how the structure, dynamics, energetics, and chemical properties of shocks are modified by UV photons and to estimate how efficiently shocks can produce line emission. Methods. We implemented several key physico-chemical processes in the Paris-Durham shock code to improve the treatment of the radiative transfer and its impact on dust and gas particles. We propose a new integration algorithm to find the steady-state solutions of magnetohydrodynamics equations in a range of parameters in which the fluid evolves from a supersonic to a subsonic regime. We explored the resulting code over a wide range of physical conditions, which encompass diffuse interstellar clouds and hot and dense photon-dominated regions. Results. We find that C-type shock conditions cease to exist as soon as G0 > 0.2 (nH/cm−3)1/2. Such conditions trigger the emergence of another category of stationary solutions, called C*-type and CJ-type shocks, in which the shocked gas is momentarily subsonic along its trajectory. These solutions are shown to be unique for a given set of physical conditions and correspond to dissipative structures in which the gas is heated up to temperatures comprised between those found in C-type and adiabatic J-type shocks. High temperatures combined with the ambient UV field favour the production or excitation of a few molecular species to the detriment of others, hence leading to specific spectroscopic tracers such as rovibrational lines of H2 and rotational lines of CH+. Unexpectedly, the rotational lines of CH+ may carry as much as several percent of the shock kinetic energy. Conclusions. Ultraviolet photons are found to strongly modify the way the mechanical energy of interstellar shocks is processed and radiated away. In spite of what intuition dictates, a strong external UV radiation field boosts the efficiency of low velocity interstellar shocks in the production of several molecular lines which become evident tracers of turbulent dissipation.

scholarly journals Particle acceleration in interstellar shocks

2019 ◽  
Vol 364 (10) ◽  
Author(s):  
Dejan Urošević ◽  
Bojan Arbutina ◽  
Dušan Onić
Keyword(s):  
Particle Acceleration ◽  
Interstellar Shocks
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