Stability of gas clouds near quasi-stellar objects

Journal Article · Thu Jul 15 04:00:00 EDT 1976 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/154501· OSTI ID:7337301

Mathews, W G

Gas clouds near quasi-stellar objects are coherently accelerated by the ultraviolet ionizing continuum in such a way that the gas density remains nearly uniform. Outward propagating sound waves, considered in the rest frame of the (accelerating) clouds, will grow in amplitude due to radiative forces unless damped by self-radiation. The instability growth rate is large only for gapproximately-greater-than0.326 kc/sub 0//sup 2/, where g is the acceleration, k=2..pi../lambda, and c/sub 0/ is the isothermal sound speed in the cloud. Relatively few optically thin QSO clouds having napproximately-greater-than10/sup 7/ cm/sup -3/ will be unstable to this process, and even these may be stabilized by the pressure in L..cap alpha.. photons.In the Appendix we show that the diffuse radiation pressure in L..cap alpha.. and in other resonance lines is negligible compared with gas pressure for most QSO clouds of interest. (AIP)

• Research Organization: Lick Observatory, Board of Studies in Astronomy and Astrophysics, University of California, Santa Cruz
• OSTI ID: 7337301
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 207:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
COSMIC GASES
COSMIC RADIO SOURCES
EMISSION SPECTRA
FLUIDS
GASES
OPACITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
QUASARS
RADIATION PRESSURE
SOUND WAVES
SPECTRA
STABILITY