相关论文: Spectral Ages of CSOs and CSS Sources

In order to understand the origin and evolution of radio galaxies, searches for the youngest such sources have been conducted. Compact-medium symmetric objects (CSO-MSOs) are thought to be the earliest stages of radio sources, with possible…

Multifrequency VLBA observations of the final group of ten objects in a sample of FIRST-based compact steep spectrum (CSS) sources are presented. The sample was selected to investigate whether objects of this kind could be relics of…

Compact symmetric objects (CSOs) are intrinsically compact extragalactic radio sources that are thought to be the progenitors of classical radio galaxies. To date, evolutionary models have mainly focused on the formation and growth of…

Radio sources with peaked spectra (peaked spectrum sources, PSS) and compact symmetric objects (CSO) are powerful, compact, and presumably young AGNs and therefore particularly suitable to study aspects of the AGN-host connection. We use a…

Two frequency observations, mainly at 1.4 and 5 GHz from the VLA, have been used to study spectral variations along the lobes of some nearby low luminosity radio galaxies that constitute a representative sample selected from the B2…

Compact Steep Spectrum (CSS) radio sources are active galactic nuclei that have radio jets propagating only on galactic scales, defined as having projected linear sizes (LS) of up to $20\,$kpc. CSS sources are generally hosted by massive…

Up till now very few dying sources were known, presumably because the dying phase is short at centimeter wavelengths. We therefore have tried to improve the statistics on sources that have ceased to be active, or are intermittently active.…

In this work, we study the optical properties of compact radio sources selected from the literature in order to determine the impact of the radio-jet in their circumnuclear environment. Our sample includes 58 Compact Steep Spectrum (CSS)…

Several samples have been proposed in the last years in order to study the properties of intrinsically small sources. In this paper, we review the properties of the main samples that are currently available, both selected on the basis of…

We present radio observations of 19 candidate compact steep-spectrum (CSS) objects selected from a well-defined, complete sample of 52 B2 radio sources of intermediate strength. These observations were made with the VLA A-array at 4.835…

Continuous injection models of spectral ageing have long been used to determine the age of radio galaxies from their integrated spectrum; however, many questions about their reliability remain unanswered. With various large area surveys…

In this paper we discuss the early phase of radio source evolution as represented by Gigahertz Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources. Correlations between their spectral peak and angular size strongly suggest…

The compact steep spectrum and gigahertz peaked spectrum sources are widely believed to be young radio sources, with ages <10^6 yr. If the activity in the nucleus is fuelled by the supply of gas, one might find evidence of this gas by…

We present the results of HST narrow band imaging of eleven Compact Steep Spectrum (CSS) radio sources. Five of them (3C 48, 3C 147, 3C303.1, 3C 277.1 and 4C 12.50) were part of a dedicated ``pointed'' program of deep line imaging ([OIII]).…

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 $\alpha <…

Compact symmetric objects (CSOs) trace the earliest phases of radio-galaxy growth; however, robust classification is difficult when radio cores are weak or invisible. We aim to develop and test a Gaia+VLBI approach that utilizes the…

VLBA observations at 18 cm are presented for 28 Compact Steep-spectrum radio Sources (CSSs) from the B3-VLA CSS sample. These sources were unresolved in previous VLA observations at high frequencies or their brightness distribution was…

We propose a new approach in determining ages of FR II type radio sources. We apply the assumed dynamical model of Kaiser et al. (1997) to a number of FR II type radio galaxies observed at different radio frequencies, and fit - for each…

We present results on global very long baseline interferometry (VLBI) observations at 327 MHz of eighteen compact steep-spectrum (CSS) and GHz-peaked spectrum (GPS) radio sources from the 3C and the Peacock & Wall catalogues. About 80 per…

Integrated spectroscopy is the method of choice for deriving the ages of unresolved stellar systems. However, hot stellar evolutionary stages, such as hot horizontal branch stars and blue straggler stars (BSSs), can affect the integrated…