Synchrotron Spectra and Ages of Compact Steep Spectrum Radio Sources
نویسندگان
چکیده
The high-frequency integrated spectra of Compact Steep Spectrum (CSS) sources show breaks with a moderate spectral steepening well fitted by continuous injection synchrotron spectra. In lobe-dominated CSS sources the radiative ages deduced by the synchrotron theory are in the range of up to 10 years, if equipartition magnetic fields are assumed. These radiative ages are well correlated with the source size indicating that the CSS sources are young. In order to maintain the frustration scenario, in which the sources’ lifetimes are ≈ 10 years, their equipartition magnetic field would be systematically decreased by a factor >∼ 20. To complete the sample used in this work, we conducted observations at 230 GHz with the IRAM 30-m telescope of those sources which did not have such high-frequency observations up to now.
منابع مشابه
Spectral Ages of CSOs and CSS Sources
This paper deals with the spectral ageing study of a representative sample of compact symmetric objects (CSOs) and compact steep spectrum (CSS) sources. Observations reveal a distinctive high-frequency steepening of the radio spectra of many of these sources. The existence of such a spectral feature is expected or may be naturally interpreted in terms of radiative ageing of synchrotron emitting...
متن کاملThe Compact Structure of Radio-Loud Broad Absorption Line Quasars
We present the results of EVN+MERLIN VLBI polarization observations of 8 Broad Absorption Line (BAL) quasars at 1.6 GHz, including 4 LoBALs and 4 HiBALs with either steep or flat spectra on VLA scales. Only one steep-spectrum source, J1122+3124, shows two-sided structure on the scale of 2 kpc. The other four steep-spectrum sources and three flat-spectrum sources display either an unresolved ima...
متن کاملClues on the nature of Compact Steep Spectrum radio sources from optical spectroscopy
New long-slit spectra are presented for a group of Compact-Steep-Spectrum (CSS) sources (i.e. powerful radio sources with sub-galactic size and steep spectral index at high radio frequencies) selected from the southern (δ < 10◦) 2-Jy sample of radio sources with redshift limit of z = 0.7. Their spectra are strong in emission lines (e.g. [O III]λ5007 and [O II]λ3727), as expected for such powerf...
متن کاملAn unbiased sample of bright southern Compact Steep Spectrum and Gigahertz Peaked Spectrum Sources
Compact Steep Spectrum (CSS) and Gigahertz Peaked Spectrum (GPS) sources are classes of compact, powerful, extragalactic objects. These sources are thought to be the earliest stages in the evolution of radio galaxies, capturing the ignition (or, in some cases, re-ignition) of the AGN. As well as serving as probes of the early stages of large-scale radio sources, these sources are good, stable, ...
متن کاملSmall-scale structures in Compact Steep-Spectrum and GHz-Peaked-Spectrum radio sources
We determine the small-scale structure for a large sample of Compact Steep Spectrum (CSS) and Gigahertz Peaked Spectrum (GPS) sources and a sample of larger radio sources at 327 MHz using the technique of Inter-Planetary Scintillation (IPS) with the Ooty Radio Telescope. Our observations provide structural information on angular scales ranging from about 50 to a few hundred milliarcsec. We esti...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1999