Journal ArticleDOI
Unified models for active galactic nuclei and quasars
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TLDR
The straw person model (SPM) as mentioned in this paper has been proposed to explain the orientation effects of active galactic nuclei (AGN) and quasars in the line of sight (LOS) images.Abstract:
Because the critical central regions of Active Galactic Nuclei (AGN) and quasars are strongly nonspherical but spatially unresolved, orientation effects have been the source of much confusion. In fact, it now appears that much of the variety in AGN types is just the result of varying orientation relative to the line of sight. We can define an extreme hypothesis,, the straw person model (SPM), in which there are two basic types of AGN: the radio quiets and the radio louds. For each type there is a range in intrinsic luminosity, and the luminosity controls some properties such as the Fanaroff and Riley classes. However, at a given intrinsic luminosity, all other properties such as spectroscopic classification and VLBI component speeds are ascribed to orientation. This model is only a caricature of the unification idea, and is already ruled out on many grounds, but it will be useful for organizing the discussion. I’ll describe what I consider to be convincing evidence that orientation effects are important and widespread. The true situation may be in some sense half way between the SPM and the hypothesis that orientation doesn’t affect classification at aIl. To us optimists, the orienration cup is half full rather than half empty. Although it is too soon to say for sure, the hypothesis that most objects’ classifications would be different if seen from other directions is a tenable one today.read more
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Journal ArticleDOI
Local and Large-Scale Environment of Seyfert Galaxies
Elias Koulouridis,Manolis Plionis,V. H. Chavushyan,V. H. Chavushyan,Deborah Dultzin-Hacyan,Yair Krongold,C. D. Goudis +6 more
TL;DR: In this paper, a three-dimensional study of the local and large-scale environment of the two main types of Seyfert AGN galaxies is presented, where the authors show that the fraction of galaxies with a close neighbor is significantly higher than that of their control (especially within 75 h-1 kpc).
Journal ArticleDOI
Magnetic Fields in Quasar Cores II
TL;DR: In this article, the authors used multi-frequency polarimetry with the Very Long Baseline Array (VLBA) telescope to reveal absolute Faraday Rotation Measures (RMs) in excess of 1000 rad/m/m in the central regions of 7 out of 8 strong quasars studied.
Journal ArticleDOI
The angular clustering of WISE-selected active galactic nuclei: Different halos for obscured and unobscured active galactic nuclei
TL;DR: In this article, the angular correlation function for a sample of ~170,000 active galactic nuclei (AGNs) extracted from the Wide-field Infrared Survey Explorer (WISE) catalog, selected to have red mid-IR colors (W1 − W2 > 0.8) and 4.6 μm flux densities brighter than 0.14 mJy, was calculated.
Journal ArticleDOI
Circumnuclear Multi-phase Gas in the Circinus Galaxy II: The Molecular and Atomic Obscuring Structures Revealed with ALMA.
TL;DR: In this article, the Atacama Large Millimeter/Submillimeter Array (ALMA) was used to map the CO(3-2) and [CI](1-0) lines, as well as their underlying continuum emission, from the central 200$ pc region of the Circinus galaxy that hosts the nearest type 2 Seyfert-class active galactic nucleus (AGN), with a spatial resolution of 6-15$ pc.
Journal ArticleDOI
Interferometer Observations of Subparsec-scale Infrared Emission in the Nucleus of NGC 4151
Mark R. Swain,Gautam Vasisht,Rachel Akeson,John D. Monnier,Rafael Millan-Gabet,Eugene Serabyn,Michelle Creech-Eakman,G. T. van Belle,J. Beletic,Chas Beichman,A. F. Boden,A. Booth,M. Mark Colavita,J. Gathright,M. Hrynevych,C. Koresko,D. Le Mignant,R. Ligon,Bertrand Mennesson,Chris Neyman,Anneila I. Sargent,M. Shao,Robert R. Thompson,Stephen C. Unwin,Peter Wizinowich +24 more
TL;DR: This article observed the nucleus of NGC 4151 at 2.2 microns using the two 10-meter Keck telescopes as an interferometer and found a marginally resolved source ~0.1 pc in diameter.
References
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Phd by thesis
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Journal Article
Superluminal Radio Sources
J. A. Zensus,T. J. Pearson +1 more
TL;DR: There are now at least 23 radio sources in which apparent superluminal motion has been found as mentioned in this paper, and the effect is not limited to the classic examples like 3C 345, but is found in objects with a wide range of characteristic properties.