Cosmological Evolution of FR-II Radio Galaxies
Paramita Barai
Physics and Astronomy, Georgia State University
PhD Prospectus Talk -- Oct 19, 2004
I seek to develop an essentially analytical model for the cosmological evolution
of Fanaroff-Riley Class II Radio Galaxies as they get older. This modeling
is needed to probe the impact of radio galaxies on the cosmological history
of the universe, which have been found to be non-trivial from several lines
of observational evidence. It has been shown that the radio lobes occupy
a significant volume of the Relevant Universe, i.e. the filaments which are
the sites of galaxy formation, during the quasar era (between redshift of
1.5 and 3). This new paradigm implies that radio galaxies have significant
effects on: triggering large scale star formation in other galaxies,
metal enrichment of the intergalactic medium, and spreading magnetic field
over large scales. I am analyzing the robustness of this scenario by examining
models that can reasonably predict the radio galaxy evolution in the universe.
As the initial step, presently I am comparing some well known and sophisticated
analytical models for power evolution of FR-II radio galaxies. The aim is
to figure out the best parameters
for each model. The observational samples are the flux-limited complete radio
surveys, 3C, 6C and 7C, taken from the literature. I perform multi-dimensional
Monte Carlo simulations in order to compare the model predictions for radio
power, size, redshift and spectral index, with the observational samples.
I then do statistical tests to find the significance level of each model
fit. The preliminary results from these studies and my future plans will
be presented.