Relativistic beaming and quasar statistics

Orr, Martin; Browne, I. W. A.

doi:10.1093/mnras/200.4.1067

Cited by 457 publications

(320 citation statements)

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“…This is absent or weak in Type 2 Seyferts. The classical review of this material is given by Weedman (1977) and a more recent one by Osterbrock (1984). The same distinction was subsequently recognized in radio galaxies (see Section VII) where Types 1 and 2 are known as BLRG (Broad Line Radio Galaxy) and NLRG (Narrow Line Radio Galaxy), respectively.…”

Section: Excitation Stratification: Linersmentioning

confidence: 84%

“…The first specific suggestion to my knowledge is the one of Adams and Weedman (1975), that the star-forming component/NLR is what is left behind when a Type 1 Seyfert expands and dissipates, switching off the active nucleus. Osterbrock (1978a) mentions a case (N7603) in which a Type 1 Seyfert apparently changed into a Type 2 Seyfert. Khachikian and Weedman (1971&) reported that Mkn 6 changed from Type 2 to Type 1.…”

Section: Excitation Stratification: Linersmentioning

confidence: 99%

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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: Excitation Stratification: Linersmentioning

confidence: 84%

Section: Excitation Stratification: Linersmentioning

confidence: 99%

Classification of active galaxies and the prospect of a unified phenomenology

Lawrence

1987

PASP

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“…The ratio of the beamed radio core flux density to the unbeamed extended radio flux density (Rc = Score Sext (1 + z) αcore−αext with αcore = 0, αext = 1) has routinely been used as a statistical indicator of Doppler beaming and thereby orientation (Orr & Browne 1982;Urry & Padovani 1995;Kharb et al 2010). In order to compare Fermi blazars with non-Fermi blazars, we also estimated Rc at 1.4 GHz.…”

Section: The Samplesmentioning

confidence: 99%

Basic properties of Fermi blazars and the ‘blazar sequence’

Xiong

Zhang

Bai

et al. 2015

Monthly Notices of the Royal Astronomical Society

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By statistically analyzing a large sample which includes blazars of Fermi detection (FBs) and non-Fermi detection (NFBs), we find that there are significant differences between FBs and NFBs for redshift, black hole mass, jet kinetic power from "cavity" power, broad-line luminosity, and ratio of core luminosity to absolute V-band magnitude (R v ), but not for ratio of radio core to extended flux (R c ) and Eddington ratio. Compared with NFBs, FBs have larger mean jet power, R c and R v while smaller mean redshift, black hole mass, broad-line luminosity. These results support that the beaming effect is main reason for differences between FBs and NFBs, and that FBs are likely to have a more powerful jet. For both Fermi and non-Fermi blazars, there are significant correlations between jet power and the accretion rate (traced by the broad-emission-lines luminosity), between jet power and black hole mass; for Fermi blazars, the black hole mass does not have significant influence on jet power while for non-Fermi blazars, both accretion rate and black hole mass have contributions to the jet power. Our results support the "blazar sequence" and show that synchrotron peak frequency (ν peak ) is associated with accretion rate but not with black hole mass.

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“…3). In the context of unified schemes these flat spectrum sources are viewed nearly pole-on as proposed by Orr & Browne (1982). 2) Steep spectrum quasars like 3C 351: the synchrotron spectrum drops from the cm to the mm wavelengths, so that the thermal FIR dust emission bump becomes clearly visible.…”

Section: Sed Shapesmentioning

confidence: 99%

The ISOPHOT - MAMBO survey of 3CR radio sources: Further evidence for the unified schemes

Haas

Muller²,

Bertoldi

et al. 2004

A&A

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Abstract. We present the complete set of ISOPHOT observations of 3CR radio galaxies and quasars, which are contained in the ISO Data Archive, providing 75 mid-and far-infrared spectral energy distributions (SEDs) between 5 and 200 µm. For 28 sources they are supplemented with MAMBO 1.2 mm observations and for 15 sources with new submillimetre data from the SCUBA archive. The sample includes flat and steep spectrum quasars, broad and narrow line radio galaxies, as well as Fanaroff-Riley FR 1 and FR 2 types. The SED shapes exhibit a diversity in the infrared (IR), ranging from a smooth dominating synchrotron component in flat spectrum sources to a thermal dust bump around 60−100 µm in steep spectrum sources. The detection rate of a thermal bump in more than 50% of the cases suggests that dust emission may be a general phenomenon in these sources. We check the orientation-dependent unified scheme, in which the powerful FR 2 narrow line galaxies are quasars viewed at high inclination, so that their nuclei are hidden behind a dust torus intercepting the optical-ultraviolet AGN radiation and reemitting it in the infrared. We find that (1) both the quasars and the galaxies show a high mid-to far-infrared luminosity ratio typical for powerful AGNs and (2) -when matched in 178 MHz luminosity -both show the same ratio of isotropic farinfrared to isotropic 178 MHz lobe power. Therefore, from our large sample investigated here we find strong evidence for the orientation-dependent unification of the powerful FR 2 galaxies with the quasars. The distribution of the dust-to-lobe luminosity ratio shows a dispersion which we suggest to be most likely due to the additional influence of evolution and environment superposed on the orientation-dependent unification. We discuss our data also in the frame of the receding torus model. At the high 178 MHz luminosities of our sources above 10 26.5 W/Hz we do not find any support for this model in its original formulation and therefore we propose a refinement: The scale height of the torus might not be independent of luminosity, rather it may increase at high luminosities due to the impact of supernovae from starbursts accompanying the AGN phenomena.

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Relativistic beaming and quasar statistics

Cited by 457 publications

References 0 publications

Classification of active galaxies and the prospect of a unified phenomenology

Classification of active galaxies and the prospect of a unified phenomenology

Basic properties of Fermi blazars and the ‘blazar sequence’

The ISOPHOT - MAMBO survey of 3CR radio sources: Further evidence for the unified schemes

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