Evidence for a large undetected population of dust-reddened quasars
Article Abstract:
At optical wavelengths the flat-spectrum radio-loud quasars are eclipsed by dust, with the dust preventing detection at different wavelengths, and the dust situated in the intervening systems is responsible for the reddening of some quasars. Therefore, assuming radio-quiet quasars have a similar amount of dust as radio-loud ones, then 80% of quasars are probably missed during bright optical quasar surveys and the missed quasars could account for the background x-ray data. However, the calculation of dust amounts within a quasar's system could inappropriately include dust in intervening systems, throwing off the average dust approximations.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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A spectre in the spectrum
Article Abstract:
Radiation pressure is an important factor driving quasar winds with about 10% of the speed of light. N. Arav and collaborators suggest that the high velocities of these outflows are due to the bulk of photons emerging from quasar's central area. Quasars are characterized by luminosities and emission lines with widths of several thousand kilometers per second. Some quasars exhibit broad absorption lines of highly ionized elements such as C3+ and N4+.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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Radiative acceleration of gas in quasars
Article Abstract:
Radiative acceleration is the most reasonable explanation for approximately 1/10 of the speed of light velocity of quasar's broad-absorption-line outflows. The acceleration is produced by the absorbance of momentum from photons on only a relatively few resonance-line transitions. This mechanism is the most likely explanation for the L-gamma-alpha ghost signature when dynamic conditions are favorable.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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