What are the gigahertz peaked-spectrum radio sources?

view Abstract Citations (284) References (120) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS What Are the Gigahertz Peaked-Spectrum Radio Sources? O'Dea, C. P. ; Baum, S. A. ; Stanghellini, C. Abstract We discuss the astrophysical implications of recent radio and optical observations of the powerful, compact gigahertz peaked-spectrum (GPS) radio sources. The defining characteristics of these objects are (1) their peaked radio spectra with narrow spectral shape and steep high- frequency spectrum, (2) low radio (and optical?) polarization, (3) large radio luminosities, and (4) mostly compact radio structure. The nature of these enigmatic objects is still not understood. However, we present some tentative conclusions and suggest a scenario based on the existing data. The turnover in the spectrum is probably due to synchrotron self- absorption, and we assume this as the basis for our inferences from the radio spectral shape. However, as we discuss below, these sources may have higher than normal electron densities in their nuclei, and it is possible that free-free absorption plays a role in at least some sources. The result that some GPS sources have a very narrow spectral shape is consistent with the hypothesis that there is a narrow range of size scales which dominate the radio luminosity; i.e., very extended (~>100 pc) and very compact ( 3). The hosts of these radio sources may be protogalaxies with very dense and clumpy interstellar media. The lower redshift GPS galaxies may have recently cannibalized a gas-rich companion, resulting in a very dense and clumpy nuclear ISM. Publication: The Astrophysical Journal Pub Date: October 1991 DOI: 10.1086/170562 Bibcode: 1991ApJ...380...66O Keywords: Astronomical Polarimetry; Extragalactic Radio Sources; Quasars; Radio Spectra; Electron Density (Concentration); Luminosity; Polarization Characteristics; Astrophysics; POLARIZATION; QUASARS; RADIATION MECHANISMS; RADIO SOURCES: GALAXIES; RADIO SOURCES: SPECTRA full text sources ADS | data products SIMBAD (95) NED (95)