Hydrogen molecules and the radiative cooling of pregalactic shocks

Journal Article · Wed Jul 01 04:00:00 EDT 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165350· OSTI ID:6016561

Shapiro, P R; Kang, H

Detailed results for the hydrodynamical, thermal, ionization, and molecular formation history of postshock cooling flows behind steady state shocks in a primordial gas at redshifts z = 5, 10, and 20 are presented and analyzed for a wide range of shock velocities from 50 to 400 km/s. The nonequilibrium results indicate that, for a significant range of shock velocities, if the shock-heated gas can cool to 10,000 K within the age of the universe, then it quite commonly forms an H2 fraction in excess of 0.001 and cools at nearly constant pressure to less than 100 K. The presence of an external flux of ionizing and dissociating radiation can, for a range of fluxes similar to that expected from a background of quasars, actually increase the peak H2 concentration to values of order 10 to the -1.5 or higher; it also increases the cooling time to 100 K. 78 references.

• Research Organization: Texas Univ., Austin
• OSTI ID: 6016561
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 318; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOUNDARY-VALUE PROBLEMS
COOLING
COSMIC GASES
ELEMENTS
FLUIDS
GALACTIC EVOLUTION
GASES
HYDROGEN
INTERGALACTIC SPACE
MOLECULES
NONMETALS
RADIATIVE COOLING
SCALING LAWS
SHOCK WAVES
SPACE
STAR EVOLUTION