The Compact Steep‐Spectrum and Gigahertz Peaked‐Spectrum Radio Sources

Abstract

ABSTRACT I review the radio to X‐ray properties of gigahertz peaked‐spectrum (GPS) and compact steep‐spectrum (CSS) sources, the current hypotheses for their origin, and their use to constrain the evolution of powerful radio galaxies. The GPS and CSS sources are compact, powerful radio sources with well‐defined peaks in their radio spectra (near 1 GHz in the GPS and near 100 MHz in the CSS). The GPS sources are entirely contained within the extent of the narrow‐line region (≲1 kpc), while the CSS sources are contained entirely within the host galaxy (≲15 kpc). The peaks in the spectra are probably due to synchrotron self‐absorption, though free‐free absorption through an inhomogeneous screen may also play a role. The turnover frequency varies with linear size l as \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra}...