A Composite Model for GHz Peaked Spectra of Radio Sources

Jun Yang, Xiang Liu, Zhi-Qiang Shen

Abstract


GHz-Peaked Spectrum (GPS) radio sources are powerful and compact sources with convex spectra. With increasing observational findings, it has been realized that either Synchrotron Self-Absorption (SSA) alone or Free-Free Absorption (FFA) alone is not enough to account for all the spectral features. We present a model consisting of an SSA region partially covered by FFA plasma, and derive a composite spectral formula. By applying the model to a sample of 19 GPS sources having strong absorption, it is found that the external FFA process makes the SSA peak frequency linearly shift to a higher (observed) peak frequency. The shift indicates that the FFA does play a role at the frequency close to the observed peak frequency.

Keywords


radio continuum: galaxies --- galaxies: active --- quasars: general

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DOI: http://dx.doi.org/10.1088/1009-9271%2F5%2F6%2F001

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Print ISSN: 1674-4527

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