Numerical simulations of suspersonic extragalactic radio jets
A boundary following code was used to simulate jets emanating from active galactic nuclei as they propagate through a bimodal external medium that first consists of an isothermal galactic halo with density falling roughly as a power law with radius, and later of a hotter, less dense, uniform intergalactic medium (IGM). By varying the beam power, the radius of the galactic halo/IGM interface, the redshift, the steepness of the power law fall-off of pressure within the halo, and the temperature ratio of the IGM to the halo, models of a wide range of radio galaxies were considered. The maximum linear sizes of the beams were found as functions of the beam and halo parameters using two different criteria, the nuclear activity time, and the point at which the advance of the beam goes subsonic. Good agreement was obtained with regard to the relationship between the observed linear size of such radio sources and both the cosmological redshift (at fixed power) and the total radio power (at fixed redshift). These results are also confirmed by a sample of fully hydrodynamical (2-D) simulations. Monte Carlo simulations which span the parameter space were employed to find the median distances for plausible distributions of the parameters for a number of constant values of density and temperature of the IGM. A statistical analysis comparing the distributions of radio galaxies in power-size-redshift bins with observational results supports the existence of a cosmologically significant IGM. The fashions in which this picture might be modified if the difference between radio galaxies, quasars, and blazars are due to orientation effects were also discussed.
- OSTI ID:
- 6231355
- Resource Relation:
- Other Information: Ph.D. Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
GALAXY NUCLEI
COMPUTERIZED SIMULATION
RADIOWAVE RADIATION
COSMOLOGY
INTERGALACTIC SPACE
MONTE CARLO METHOD
RADIO GALAXIES
RED SHIFT
THEORETICAL DATA
WAVE PROPAGATION
COSMIC RADIO SOURCES
DATA
ELECTROMAGNETIC RADIATION
GALAXIES
INFORMATION
NUMERICAL DATA
RADIATIONS
SIMULATION
SPACE
640105* - Astrophysics & Cosmology- Galaxies