Probing spectral properties of radio-quiet quasars searched for optical microvariability - II
نویسندگان
چکیده
منابع مشابه
The radio properties of radio-quiet quasars
Although radio-quiet quasars (RQQs) constitute > ∼ 90% of optically-identified quasar samples their radio properties are only poorly understood. In this paper we present the results of a multi-frequency VLA study of 27 low-redshift RQQs. We detect radio emission from 20 objects, half of which are unresolved (≤ 0.24). In cases where significant structure can be resolved, double, triple and linea...
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We have performed a successful targeted search for a population of red, radio-quiet, and probably absorbed quasars. Radio-quiet, optically red ROSAT PSPC X-ray sources brighter than 1 ] 10~13 ergs cm~2 s~1 were searched for red (O[E [2.0, O1 20) counterparts in the Automated Plate-measuring Machine catalog of Palomar Sky Survey objects. Of 45 objects for which we obtained adequate followup opti...
متن کاملProbing the Hard X–ray Properties of High-redshift Radio-quiet Quasars with Asca
This paper reports the X-ray spectral analysis of 5 high-redshift (z≥2) radio-quiet quasars observed by ASCA. A simple power law continuum plus cold Galactic absorption model well fits all the spectra (tipically between ∼ 2–30 keV in the sources frame). Neither the X–ray spectral hardening, attributed to a reflection component and observed in Seyfert galaxies, nor the excess absorption previous...
متن کاملIntra-night Optical Variability of BL Lacs, Radio-Quiet Quasars and Radio-Loud Quasars
We report monitoring observations of 20 high-luminosity AGN, 12 of which are radioquiet quasars (RQQs). Intra-night optical variability (INOV) was detected for 13 of the 20 objects, including 5 RQQs. The variations are distinctly stronger and more frequent for blazars than for the other AGN classes. By combining these data with results obtained earlier in our program, we have formed an enlarged...
متن کاملThe central engines of radio-quiet quasars
Two rival hypotheses have been proposed for the origin of the compact radio flux observed in radio-quiet quasars (RQQs). It has been suggested that the radio emission in these objects, typically some two or three orders of magnitude less powerful than in radio-loud quasars (RLQs), represents either emission from a circumnuclear starburst or is produced by radio jets with bulk kinetic powers ∼ 1...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2011
ISSN: 0035-8711
DOI: 10.1111/j.1365-2966.2011.19985.x