The evolution of GHz-peaked-spectrum radio sources
نویسنده
چکیده
Observations of extended radio emission in some GPS sources suggest that they may not be a young version of the classical doubles. The compact source would be confined by the presence of a dense medium in the center of the galaxy. The existence of such a dense environment is supported by the observation of disturbed optical morphologies indicating galaxygalaxy interaction or mergers. A simple model is formulated to calculate the velocity of advance of the jet as it propagates in a cloudy medium. Different forms of interaction of the jet with the clouds are studied as well as the distribution of gas and clouds on scales smaller than 1 kpc around the central engine. It is found that the age of these GPS sources is of the same order as that of the extended radio sources and that the jet propagates either by scattering clouds or by drilling its way through them.
منابع مشابه
EVN observations of eleven GHz - Peaked - Spectrum radio sources at 2 . 3 / 8 . 4 GHz
We present results of EVN observations of eleven GHz-Peaked-Spectrum (GPS) radio sources at 2.3/8.4 GHz. These sources are from the classical " bright " GPS source samples with peak flux densities > 0.2 Jy and spectral indices α < −0.2 (S ∝ ν −α) in the optically thick regime of their convex spectra. Most of the target sources did not have VLBI images at the time this project started. The aim o...
متن کاملRadio spectra of Gigahertz Peaked Spectrum radio sources
Awell defined sample of 72 Gigahertz Peaked Spectrum radio sources is compiled, having turnover frequencies in the range of 0.5 – 10 GHz. Using this sample, the canonical GPS radio spectrum is constructed, which is found to have a constant shape, independent of AGN type, redshift or radio luminosity. A possible deficiency of low turnover frequencies at high redshift is found, which may reflect ...
متن کاملVLBI observations of nineteen GHz-Peaked-Spectrum radio sources at 1.6 GHz
Abstract. Aims and Methods: We present the results of VLBI observations of nineteen GHz-Peaked-Spectrum (GPS) radio sources at 1.6 GHz. Of them, 15 sources are selected from the Parkes Half Jansky (PHJ) sample (Snellen 2002), 4 others are from our previous observation list. We aimed at imaging the structure of GPS sources, searching for Compact Symmetric Objects (CSOs) and studying the absorpti...
متن کاملSurveys of Extragalactic Sources with Planck
Although the primary goal of ESA’s Planck mission is to produce high resolution maps of the temperature and polarization anisotropies of the Cosmic Microwave Background (CMB), its high-sensitivity all-sky surveys of extragalactic sources at 9 frequencies in the range 30–860 GHz will constitute a major aspect of its science products. In particular, Planck surveys will provide key information on ...
متن کاملAstronomy and Astrophysics Vlba Observations of Ghz-peaked-spectrum Radio Sources at 15 Ghz
We present VLBA observations at 15 GHz of ten GHz Peaked Spectrum (GPS) radio sources. The cores are often difficult or impossible to locate. When likely cores are found, they account for a small fraction of the flux density in GPS galaxies around or below 2%, while in GPS quasars they can account for more than 20% of the total flux density. We detect low polarization in the GPS sources – i.e.,...
متن کاملAn evolutionary model for GHz peaked spectrum sources Predictions for high frequency surveys
We have explored, in the general framework of the “young source” scenario, evolutionary models for GHz Peaked Spectrum (GPS) galaxies and quasars which reproduce the observed counts, redshift and peak frequency distributions of currently available samples. Substantially different cosmological evolution properties are found for the two populations: the quasar luminosity function must evolve stro...
متن کامل