منابع مشابه
Radio-quiet Red Quasars
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...
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Webster et al (1995) claimed that up to 80% of QSOs may be obscured by dust. They inferred the presence of this dust from the remarkably broad range of B?K optical-infrared colours of a sample of at-spectrum PKS radio QSOs. If such dust is typical of QSOs, it will have rendered invisible most of those which would otherwise been have detected by optical surveys. We used the William Herschel Tele...
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We present results of a study of 12 dust-reddened quasars with 0.4 < z < 2.65 and reddenings in the range 0.15 < E(B − V ) < 1.7. We obtained ACIS-S X-ray spectra of these quasars, estimated the column densities towards them, and hence obtained the gas:dust ratios in the material obscuring the quasar. We detect all but one of the red quasars in the X-rays. Even though there is no obvious correl...
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We explore the role that red giants might play in the fuelling and evolution of Active Galactic Nuclei. Due to their large radii and the low binding energy of the stellar envelope, giants are vulnerable to envelope stripping from collisions with the accretion disk. Using hydrodynamic simulations we show that such collisions will typically deposit a substantial fraction of the envelope mass into...
متن کاملRed synchrotron jets in Parkes quasars
We present model fits to spectral energy distributions in the optical and NIR of > 100 flat-spectrum radio quasars from the Parkes Half-Jansky Flat-spectrum Sample. We find that ∼ 40% of the sources have power-law SEDs, while a similar number show evidence for two primary components: a blue power law and optical synchrotron emission. The blue power law is similar to the dominant component obser...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2018
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/201731963