The spectral turnover-linear size relation and the dynamical evolution of compact steep spectrum sources

Abstract

Analytical and numerical methods have been used to develop a dynamical model for the evolution of the linear size, D, of compact steep spectrum (CSS) sources through the ambient medium of density, ne, within a characteristic time, T. This shows that the empirical relation between spectral turnover, νp, and D implies that νp∼n0.35e, suggesting that the spectral turnover constitutes a characteristic signature of dense gases around CSS sources.

On Jet Opening Angle and Dynamical Evolution of Some Powerful Extragalactic Radio Sources

“…Moreover, within the host galaxy, the ambient number density, , has been reported to decline from the central core by ~ . (where is linear size of the radio source) [5,7,8]. This shows that ambient density falls off according to the equation as distance increases from the central core.…”

“…5 d 2 03 4 ε 2 ⁄ has been replaced with g. The last equation simply shows that jet opening angle decreases with an increase in the source ambient density. In addition, it has been pointed out by some authors [3,8,12] that linear size depends on the source ambient density according to the relation, ~ .…”

“…where J has been replaced with J = 5: < ⁄ for homogenous ambient media [8].For the radio source, 3C405 (i.e., Cygnus A), K ; can be written in terms of by…”

“…However, by definition, + $< and + 9 can be expressed respectively by [8,15] where H < is mass of jet, I is acceleration, J is source age, and K ; is radius of lobe.…”

“…With an assumption that, in general, jets in EGRSs propagate through a homogenous dense medium, the linear size, , of the source can be written according to the equation [8]:…”