Is every quasar beamed?

Barthel, P. D.

doi:10.1086/167038

Cited by 780 publications

(794 citation statements)

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“…In this orientation-based unified scheme (OUS), because of the smaller inclinations of the radio axes of the quasars with respect to the observer's line of sight, the observed radio sizes of the quasars will be foreshortened due to the geometry and should appear systematically smaller than those of the HEGs. It is a popular notion that ξ c ∼ 45 • and that in the 3CRR catalogue the observed sizes of quasars are accordingly about a factor of two smaller as compared to those of radio galaxies (Barthel 1989;Urry & Padovani 1995;Peterson 1997). …”

Section: The Samplementioning

confidence: 99%

A large anisotropy in the sky distribution of 3CRR quasars and other radio galaxies

Singal

2015

Astrophys Space Sci

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We report the presence of large anisotropies in the sky distributions of powerful extended quasars as well as some other sub-classes of radio galaxies in the 3CRR survey, the most reliable and most intensively studied complete sample of strong steep-spectrum radio sources. The anisotropies lie about a plane passing through the equinoxes and the north celestial pole. Out of a total of 48 quasars in the sample, 33 of them lie in one half of the observed sky and the remaining 15 in the other half. The probability that in a random distribution of 3CRR quasars in the sky, statistical fluctuations could give rise to an asymmetry in observed numbers up to this level is only ∼ 1%. Also only about 1/4th of Fanaroff-Riley 1 (FR1) type of radio galaxies lie in the first half of the observed sky and the remainder in the second half. If we include all the observed asymmetries in the sky distributions of quasars and radio galaxies in the 3CRR sample, the probability of their occurrence by a chance combination reduces to ∼ 2×10 −5 . Two pertinent but disturbing questions that could be raised here are -firstly why should there be such large anisotropies present in the sky distribution of some of the strongest and most distant discrete sources, implying inhomogeneities in the universe at very large scales (covering a fraction of the universe)? Secondly why should such anisotropies lie about a great circle decided purely by the orientation of earth's rotation axis and/or the axis of its revolution around the sun? Are these alignments a mere coincidence or do they imply that these axes have a preferential placement in the larger scheme of things, implying an apparent breakdown of the Copernican principle or its more generalization, cosmological principle, upon which the standard cosmological model is based upon?

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Section: The Samplementioning

confidence: 99%

A large anisotropy in the sky distribution of 3CRR quasars and other radio galaxies

Singal

2015

Astrophys Space Sci

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“…Heckman et al (1992Heckman et al ( , 1994 claim that, if long wavelength FIR emission is due to thermal re-radiation by circumnuclear dust, quasars and radio galaxies are expected to show similar outputs of such radiation, because of the optical thinness of the thermal emission. But they show that 3C quasars are more powerful FIR (60 µm) sources than 3C radio galaxies and this result can be used either to disprove the unification scheme of quasars and radio galaxies proposed by Barthel (1989), or to state that the FIR emission from quasars cannot be due to thermal reradiation from dust unless the emitting region is very optically thick, resulting in some degree of radiated anisotropy (Pier & Krolik 1992;Granato & Danese 1996).…”

Section: Introductionmentioning

confidence: 98%

Far-infrared/millimetre emission in 3C sources

Andreani¹,

Fosbury²,

Bemmel³

et al. 2002

A&A

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Abstract. We present far-infrared and millimetric observations of a sample of 3C objects. Millimetre data were taken at 1.25 mm with the IRAM 30 m antenna feeding the MPIfR bolometer array. Mid-infrared (MIR) and far-infrared (FIR) photometry were carried out with the ISOCAM and ISOPHOT cameras on the ISO Satellite. Additional FIR IRAS observations are also included. We present the entire Spectral Energy Distributions (SEDs) from the UV to radio and discuss the emitting mechanisms. Two composite spectra, one for the radio galaxies and one for the radio quasars, are built in the object rest frame. While the SEDs of the two classes differ, they are indistinguishable in the MIR and FIR range where they probably arise as thermal emission from a dusty torus and a larger-scale (cooler) dust distribution in the host galaxy.

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“…1,2,3,4,6 are also available in electronic form at the CDS via anonymous ftp to: cdsarc.ustrasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/ Abstract.html extragalactic radiosources (Barthel 1989) through, for instance, a direct comparison of the observed angular sizes of radiogalaxies and quasars in the same redshift range.…”

Section: Introductionmentioning

confidence: 99%

The B3-VLA quasar sample

Vigotti

Vettolani

Merighi

et al. 1997

Astron. Astrophys. Suppl. Ser.

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Abstract. A new low frequency radio selected Sample of 125 Quasars complete down to 100 mJy at 408 MHz is presented in this paper. The sample is a part of the B3-VLA sample: 1050 radiosources selected from the B3 catalogue at 408 MHz and observed at the VLA (1465 MHz, C and A configurations). Out of the 352 sources, identified on the POSS-I down to m r ∼ 20.0, 172 are quasar candidates. In this paper we give the final assessment of the quasar sample from spectroscopic observations of the candidates. The final complete quasar sample consists of 125 objects. Furthermore 3 Bl Lac objects have been identified and two Bl Lac candidates.

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Is every quasar beamed?

Cited by 780 publications

References 0 publications

A large anisotropy in the sky distribution of 3CRR quasars and other radio galaxies

A large anisotropy in the sky distribution of 3CRR quasars and other radio galaxies

Far-infrared/millimetre emission in 3C sources

The B3-VLA quasar sample

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