The Nature of Radio‐Intermediate Quasars: What Is Radio‐loud and What Is Radio‐quiet? | Zendy

H. Falcke | Zendy; W. A. Sherwood | Zendy; Alok R. Patnaik | Zendy

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The Nature of Radio‐Intermediate Quasars: What Is Radio‐loud and What Is Radio‐quiet?

Author(s) -

H. Falcke,

W. A. Sherwood,

Alok R. Patnaik

Publication year - 1996

Publication title -

the astrophysical journal

Language(s) - English

Resource type - Journals

eISSN - 1538-4357

pISSN - 0004-637X

DOI - 10.1086/177956

Subject(s) - quasar , physics , astrophysics , ovv quasar , radio spectrum , astronomy , galaxy

We have performed quasi-simultaneous radio flux density measurements at 2.7and 10 GHz for all PG quasars with radio flux densities between 4-200 mJy. Wefind that a large fraction of these sources are variable, flat-spectrumquasars. This brings the total fraction of flat-spectrum quasars with a ratiobetween radio and optical flux of R>10 - a value previously used to define aradio-loud quasar - to 40% in the PG quasar sample. We also find that themedian R-parameter of these flat-spectrum quasars is lower than those ofsteep-spectrum radio-loud quasars. This contradicts the predictions of theunified scheme and the idea that all flat-spectrum, core-dominated quasars arerelativistically boosted lobe-dominated quasars. We show that this discrepancyis due to a population of flat-spectrum radio-intermediate quasars with25

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