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Title: Excess 2 centimeter emission - a new continuum component in the spectra of radio-quiet quasars

Abstract

The centimeter and millimeter regions of the spectra of radio-quiet quasars and luminous Seyfert 1 nuclei are examined. It is found that steep-spectrum optically thin synchrotron radiation dominates in the 20 cm to 6 cm region of most objects. A flat or rising component which becomes dominant by 2 cm in nine of the 17 cases in the sample is identified as a new continuum component called the high-frequency excess (HFE). The luminous quasar PG 1634 + 706, for which HFE dominates throughout the centimeter region, is discussed in detail. Possible causes of the HFE include self-absorbed synchrotron sources, about 10 to the 6 K nuclear free-free sources, and about 1000 K free-free sources from associated nuclear starbursts. It is concluded that because the brightness temperature predictions are very distinct, future observations will determine which explanation is correct. 27 references.

Authors:
;
Publication Date:
Research Org.:
Space Telescope Science Institute, Baltimore, MD (USA); National Radio Astronomy Observatory, Charlottesville, VA (USA); Haystack Observatory, Westford, MA (USA)
OSTI Identifier:
6685096
Resource Type:
Journal Article
Journal Name:
Astrophys. J.; (United States)
Additional Journal Information:
Journal Volume: 332
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALAXY NUCLEI; MICROWAVE SPECTRA; QUASARS; SEYFERT GALAXIES; ENERGY SPECTRA; RADIOWAVE RADIATION; SYNCHROTRON RADIATION; BREMSSTRAHLUNG; COSMIC RADIO SOURCES; ELECTROMAGNETIC RADIATION; GALAXIES; RADIATIONS; SPECTRA; 640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources; 640105 - Astrophysics & Cosmology- Galaxies

Citation Formats

Antonucci, R, and Barvainis, R. Excess 2 centimeter emission - a new continuum component in the spectra of radio-quiet quasars. United States: N. p., 1988. Web. doi:10.1086/185256.
Antonucci, R, & Barvainis, R. Excess 2 centimeter emission - a new continuum component in the spectra of radio-quiet quasars. United States. https://doi.org/10.1086/185256
Antonucci, R, and Barvainis, R. 1988. "Excess 2 centimeter emission - a new continuum component in the spectra of radio-quiet quasars". United States. https://doi.org/10.1086/185256.
@article{osti_6685096,
title = {Excess 2 centimeter emission - a new continuum component in the spectra of radio-quiet quasars},
author = {Antonucci, R and Barvainis, R},
abstractNote = {The centimeter and millimeter regions of the spectra of radio-quiet quasars and luminous Seyfert 1 nuclei are examined. It is found that steep-spectrum optically thin synchrotron radiation dominates in the 20 cm to 6 cm region of most objects. A flat or rising component which becomes dominant by 2 cm in nine of the 17 cases in the sample is identified as a new continuum component called the high-frequency excess (HFE). The luminous quasar PG 1634 + 706, for which HFE dominates throughout the centimeter region, is discussed in detail. Possible causes of the HFE include self-absorbed synchrotron sources, about 10 to the 6 K nuclear free-free sources, and about 1000 K free-free sources from associated nuclear starbursts. It is concluded that because the brightness temperature predictions are very distinct, future observations will determine which explanation is correct. 27 references.},
doi = {10.1086/185256},
url = {https://www.osti.gov/biblio/6685096}, journal = {Astrophys. J.; (United States)},
number = ,
volume = 332,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 1988},
month = {Thu Sep 01 00:00:00 EDT 1988}
}