On markaryan 6 and the problem of the intermediate Sy 1.5 type

Khachikyan, É. E.; Popov, V. N.; Egiazaryan, A. A.

doi:10.1007/bf01005668

Cited by 1 publication

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“…Pension and Perez (1984) saw a very clear and spectacular change in the continuum and BLR of the most famous Seyfert, NGC 4151, and advanced the idea that Seyferts could change types on a very fast time scale (decades). Changes from Type 2 to Type 1 have also been seen in Mkn 6 by Khachikian, Popov, and Egiazaryan (1982) and in NGC 1566 by Alloin et al (1984). Even without a starburst fossil, as in the Adams and Weedman idea, the NLR would remain essentially unchanged over such time scales because of its large size.…”

Section: Hi Some General Pointsmentioning

confidence: 95%

Classification of active galaxies and the prospect of a unified phenomenology

Lawrence

1987

PASP

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The observational classification of active galaxies is reviewed and its likely meaning discussed. A large number of facts and ideas are examined, but a particular set of ideas is stressed as our best hope for a unified phenomenology, as follows. There is only one kind of Active Galactic Nucleus (AGN). The observed variety arises from three degrees of freedom: (1) Dust opacity, which produces the distinction between Type 1 and Type 2 AGN. (2) Viewing angle of a relativistic jet, which produces the distinction between blazars and Type 1 AGN. (3) Duty cycle of activity (i.e., fraction of time spent "on") which produces the distinction between radio-loud and radio-quiet AGN. The duty cycle may be related to the mass of the spheroidal component of the parent galaxy. A fourth degree of freedom is, of course, the overall luminosity. Also, it has recently become clear that there is considerable latitude in the physical condition of gas surrounding the nucleus.For theories of AGN to be presented with a real challenge, we need two things. First, a clear qualitative phenomenology, such as the possibility outlined above, must be decided upon. Second, we need to formulate a quantitative phenomenology.

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Section: Hi Some General Pointsmentioning

confidence: 95%

Classification of active galaxies and the prospect of a unified phenomenology

Lawrence

1987

PASP

View full text Add to dashboard Cite

show abstract

On markaryan 6 and the problem of the intermediate Sy 1.5 type

Cited by 1 publication

References 7 publications

Classification of active galaxies and the prospect of a unified phenomenology

Classification of active galaxies and the prospect of a unified phenomenology

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