Radiation-Pressure Mass Loss from Quasi-Stellar Objects

AbstractWe present MIR spectroscopy and photometry obtained with CanariCam on the 10.4 m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous quasi-stellar objects (QSOs). We find that for the majority of QSOs the MIR emission is unresolved at angular scales ∼0.3 arcsec. We derive the properties of the dusti tori that surround the nucleus based on these observations and find significant differences in the parameters compared with a sample of Seyfert 1 and 2 nuclei. We also find evidence for polycyclic aromatic hydrocarbon (PAH) features in the spectra, indicative of star formation, more centrally peaked (on scales of a few hundred pc) than previously believed.

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Radiation-Driven Stellar Eruptions

Galaxies ◽

10.3390/galaxies8010010 ◽

2020 ◽

Vol 8 (1) ◽

pp. 10 ◽

Cited By ~ 2

Author(s):

Kris Davidson

Keyword(s):

Mass Loss ◽

Radiation Pressure ◽

Central Region ◽

Massive Stars ◽

Variable Stars ◽

Blast Waves ◽

Subsequent Evolution ◽

Fundamental Causes ◽

Radiative Output ◽

Luminous Blue Variable

Very massive stars occasionally expel material in colossal eruptions, driven by continuum radiation pressure rather than blast waves. Some of them rival supernovae in total radiative output, and the mass loss is crucial for subsequent evolution. Some are supernova impostors, including SN precursor outbursts, while others are true SN events shrouded by material that was ejected earlier. Luminous Blue Variable stars (LBV’s) are traditionally cited in relation with giant eruptions, though this connection is not well established. After four decades of research, the fundamental causes of giant eruptions and LBV events remain elusive. This review outlines the basic relevant physics, with a brief summary of essential observational facts. Reasons are described for the spectrum and emergent radiation temperature of an opaque outflow. Proposed mechanisms are noted for instabilities in the star’s photosphere, in its iron opacity peak zones, and in its central region. Various remarks and conjectures are mentioned, some of them relatively unfamiliar in the published literature.

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Classification of Compact Objects: QSS, QSOs, N-Type and Compact Galaxies, Seyfert and Galactic Nuclei

Symposium - International Astronomical Union ◽

10.1017/s0074180900005386 ◽

1972 ◽

Vol 44 ◽

pp. 97-103

Author(s):

W. W. Morgan

Keyword(s):

Galactic Nuclei ◽

Seyfert Galaxy ◽

Classification Criteria ◽

Compact Objects ◽

Stellar Objects ◽

Quasi Stellar Objects ◽

Compact Galaxies

Some methods currently in use for the classification of the optical forms of the ‘compact’ galaxies and quasi-stellar objects are reviewed. It is shown that the category ‘Seyfert Galaxy’ is basically a spectroscopic (rather than a form) classification.An optical form-classification is described which is, in principle, identical with published classification criteria for QSO, N-type, and compact objects. The importance of maintaining rigid form-standards is emphasized.

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On the Space Distribution of Identified Quasi-stellar Objects and Radiogalaxies

Nature ◽

10.1038/216351a0 ◽

1967 ◽

Vol 216 (5113) ◽

pp. 351-352 ◽

Cited By ~ 6

Author(s):

G. R. BURBIDGE ◽

F. HOYLE

Keyword(s):

Space Distribution ◽

Stellar Objects ◽

Quasi Stellar Objects

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Nature of strong radio emission from quasi-stellar objects

Physics Letters ◽

10.1016/0031-9163(64)90114-3 ◽

1964 ◽

Vol 9 (2) ◽

pp. 138-139 ◽

Cited By ~ 2

Author(s):

L. Gold ◽

J.W. Moffat

Keyword(s):

Radio Emission ◽

Stellar Objects ◽

Quasi Stellar Objects

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THE HIGH A V Quasar Survey: Reddened Quasi-Stellar Objects selected from optical/near-infrared photometry. II.

The Astrophysical Journal Supplement Series ◽

10.1088/0067-0049/217/1/5 ◽

2015 ◽

Vol 217 (1) ◽

pp. 5 ◽

Cited By ~ 28

Author(s):

J.-K. Krogager ◽

S. Geier ◽

J. P. U. Fynbo ◽

B. P. Venemans ◽

C. Ledoux ◽

...

Keyword(s):

Near Infrared ◽

Infrared Photometry ◽

Stellar Objects ◽

Quasi Stellar Objects

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The Origin of Absorption Spectra in Quasi-Stellar Objects

Symposium - International Astronomical Union ◽

10.1017/s0074180900068406 ◽

1980 ◽

Vol 92 ◽

pp. 107-117 ◽

Cited By ~ 1

Author(s):

Ray J. Weymann

Keyword(s):

Absorption Line ◽

Absorption Spectra ◽

Classification Scheme ◽

Spectral Characteristics ◽

Type A ◽

Galactic Halos ◽

Evolutionary Sequence ◽

Rich Cluster ◽

Stellar Objects ◽

Quasi Stellar Objects

A classification scheme for QSO absorption line spectra is described which ascribes the origin of the lines to at least four mechanisms: (A) Explosive ejection of material at speeds up to 0.1 c. (B) Absorption by highly ionized material moving in a rich cluster in which the QSO is embedded. (C-1) Cosmologically distant intervening material with ‘normal’ abundances, probably associated with large galactic halos. (C-2) Cosmologically distant intervening material consisting of primordial uncondensed gas. Examples of each type of spectra are given and their ionization and other spectral characteristics discussed. The similarity between the development of novae spectra and a possible evolutionary sequence of the explosive ejecta of type A is striking and suggestive. Several difficulties and unsolved problems involving this scheme are noted. Finally, we speculate on the interpretation of two interesting objects (PKS 0237-23 and the ‘twin quasars’ 0957+56A,B) in the context of this scheme.

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