Computer Science – Sound
Scientific paper
Jan 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993egte.conf..338b&link_type=abstract
In NASA. Ames Research Center, The Evolution of Galaxies and Their Environment p 338 (SEE N93-26706 10-90)
Computer Science
Sound
5
Cosmic Gases, Emission Spectra, Galactic Halos, Gas Cooling, Gas Density, Gas Ionization, Isochoric Processes, Nonequilibrium Ionization, Radiative Transfer, Acoustic Velocity, Flow Velocity, Photoionization, Time Dependence, Ultraviolet Radiation, X Ray Sources
Scientific paper
We have calculated the time-dependent, nonequilibrium thermal and ionization history of gas cooling radiatively from 10(exp 6) K in a one-dimensional, planar, steady-state flow model of the galactic fountain, including the effects of radiative transfer. Our previous optically thin calculations explored the effects of photoionization on such a flow and demonstrated that self-ionization was sufficient to cause the flow to match the observed galactic halo column densities of C 4, Si 4, and N 5 and UV emission from C 4 and O 3 in the constant density (isochoric) limit, which corresponded to cooling regions homogeneous on scales D less than or approximately equal to 1 kpc. Our new calculations which take full account of radiative transfer confirm the importance of self-ionization in enabling such a flow to match the data but allow a much larger range for cooling region sizes, i.e. D(sub 0) greater than or approximately equal to 15 pc. For an initial flow velocity v(sub 0) approximately equal to 100 km/s, comparable to the sound speed of a 10(exp 6) K gas, the initial density is found to be n(sub h,0) is approximately 2 x 10(exp -2) cm(exp -3), in reasonable agreement with other observation estimates, and D(sub 0) is approximately equal to 40 pc. We also compare predicted H(alpha) fluxes, UV line emission, and broadband x-ray fluxes with observed values. One dimensional numerical hydrodynamical calculations including the effects of radiative cooling are also presented.
Benjamin Robert A.
Shapiro Paul R.
No associations
LandOfFree
The absorption and emission spectrum of radiative cooling galactic fountain gas does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The absorption and emission spectrum of radiative cooling galactic fountain gas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The absorption and emission spectrum of radiative cooling galactic fountain gas will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1260310