Bibcode
DOI
Tenorio-Tagle, Guillermo; Munoz-Tunon, C.; Perez, Enrique; Melnick, Jorge
Referencia bibliográfica
Astrophysical Journal Letters v.490, p.L179
Fecha de publicación:
12
1997
Número de citas
19
Número de citas referidas
17
Descripción
The faint extended broad (>=1000 km s-1) optical emission lines
associated with giant H II regions are shown here to be produced in a
shell of ISM material smoothly accelerated soon after breakout.
Two-dimensional calculations of remnants caused by a strong energy
deposit in a low metal abundance ISM are here shown to undergo breakout
once encountering a steep density gradient, leading to a fast-moving
shell capable of producing the broad and faint emission lines. Energetic
sources lead to fast, thick, and hot shells, and when evolving in a
low-metallicity ISM, to quasi-adiabatic shells that strongly delay their
fragmentation owing to Rayleigh-Taylor instabilities. At the same time,
these are smoothly accelerated to reach large distances from the
breakout point. The shell acceleration is promoted by the passage of
several shocks with small relative speeds, caused by the continuous push
exerted by the hot gas that steadily increases its speed to fill the
deformed superbubble volume.