A Multi-wavelength Study of Galaxy Clusters Hosting Radio Sources

A Multi-wavelength Study of Galaxy Clusters Hosting Radio Sources
Author: Joshua David Wing
Publisher:
Total Pages: 472
Release: 2013
Genre:
ISBN:

Abstract: Galaxy clusters play an important role in understanding the formation of structure in the Universe and can be used to constrain cosmological parameters. Thousands of clusters are known in the nearby Universe, but few are confirmed at large distances. Remote clusters provide a view of the early Universe, and are important for studying galaxy evolution. Here, I describe a technique for finding distant clusters using bent, double-lobed radio galaxies. These radio sources are active galactic nuclei (AGN) that result from outflows of material surrounding supermassive black holes in the centers of massive galaxies. These outflows are typically bent as a result of the relative motion between the host galaxy and the surrounding hot gas that fills clusters. Using the Sloan Digital Sky Survey (SDSS) and the Faint Images of the Radio Sky at Twenty-centimeters ( FIRST ) survey, I determine the frequency with which bent radio sources are associated with rich galaxy clusters in the nearby Universe (z 0.5), as compared to non-bent radio sources. I find that 60% of bent radio sources are located in rich cluster environments, compared to 10 - 20% of non-bent radio sources. Therefore, bent radio sources are efficient tracers for clusters and are useful as beacons of clusters at large distances. Bent radio sources may achieve their morphologies through large-scale cluster mergers that set the intracluster medium (ICM) in motion. Using a suite of substructure tests, I determine the significance of optical substructure in clusters containing radio sources. I find no preference for substructure in clusters with bent double-lobed sources compared to other types of radio sources, indicating that bent sources will not necessarily preferentially select clusters undergoing recent large-scale mergers. Having established that bent radio sources efficiently locate clusters, I have obtained deep, follow-up observations at optical and near-infrared wavelengths to uncover associated distant cluster candidates. In addition, a large Spitzer Space Telescope survey is underway to observe all bent sources not detected in the SDSS. Follow-up observations reveal a large number of high-redshift candidates. Further study of these objects will lend insight into galaxy formation and evolution and feedback between an AGN and its environment at high-redshift for clusters with a range of masses.

Multi-Wavelength Continuum Emission of AGN

Multi-Wavelength Continuum Emission of AGN
Author: International Astronomical Union. Symposium
Publisher: Springer
Total Pages: 570
Release: 1994-04-30
Genre: Science
ISBN:

(Note: the title actually, but erroneously, shown on the dust jacket, cover, and title page is Multi-Wavelength Continuum Emission of AGN, which is really only the heading of the first section of the volume. Because the correct, but omitted, title subsumes the erroneous title, Book News uses it in order to most accurately establish the reach of the volume.) The proceedings, then, of IAU Symposium No. 159, held in Geneva, Switzerland, August-September 1993, contain almost all of the presentations given at the conference both as posters and as oral invited and contributed papers. They address topics in multi- wavelength continuum emission of AGN; new observations of AGN with specific instruments; variability; correlations between emission components; AGN physics and models; unified schemes and relations with other types of objects; continuum studies; emission processes; x-rays and higher energies; variability; radio emission (maps); line studies; disk structure and emission; and statistical studies and evolution. Annotation copyright by Book News, Inc., Portland, OR

Multiwavelength Agn Surveys - Proceedings Of The Guillermo Haro Conference 2003

Multiwavelength Agn Surveys - Proceedings Of The Guillermo Haro Conference 2003
Author: Raul Mujica
Publisher: World Scientific
Total Pages: 459
Release: 2004-10-12
Genre: Science
ISBN: 9814481742

The huge amount of data obtained by surveys in all wavebands, from radio to X-rays, has allowed major progress in the understanding of Active Galactic Nuclei and of their cosmic evolution. This book contains the proceedings of a conference intended to give a broad overview of the recent results obtained by recent AGN surveys over the whole electromagnetic spectrum. Topics which were discussed during the conference and are included in this volume are: AGN evolution, contribution to the cosmic background, AGN luminosity functions in different wavebands, multiwavelength properties of AGN, unified model and unconventional AGN, connection with the host galaxies, co-evolution of AGN and galaxies, implications for the local density of supermassive black holes. Future AGN surveys planned with forthcoming new observational facilities are also included.The proceedings have been selected for coverage in:• Index to Scientific & Technical Proceedings® (ISTP® / ISI Proceedings)• Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)• CC Proceedings — Engineering & Physical Sciences

Multiwavelength AGN Surveys and Studies (IAU S304)

Multiwavelength AGN Surveys and Studies (IAU S304)
Author: Areg M. Mickaelian
Publisher: Cambridge University Press
Total Pages: 0
Release: 2014-08-21
Genre: Science
ISBN: 9781107045248

Active galactic nuclei (AGN) are among the most interesting astrophysical objects in the Universe. IAU Symposium 304, dedicated to marking the centenary of B. E. Markarian's birth, addresses the most important questions in this area: understanding the possible evolutionary and/or physical connections between the different classes of AGN; the relation of AGN to their host galaxies; and understanding the true fraction of heavily obscured AGN in order to determine the true AGN luminosity function and its variation with redshift. This volume's topics include: historical spectral and colorimetric surveys, multiwavelength AGN surveys, AGN statistics, unification and other models of AGN, AGN feedback in galaxies and clusters, their host galaxies and environments, binary AGN and merging supermassive black holes, AGN variability, and future large projects. This fresh summary of AGN surveys is especially useful for researchers engaged in this exciting field and helping them plan for future surveys and observations.

Multi-Wavelength Continuum Emission of AGN

Multi-Wavelength Continuum Emission of AGN
Author: T.J.-L. Courvoisier
Publisher: Springer
Total Pages: 0
Release: 1994-05-14
Genre: Science
ISBN: 9789401095372

Active Galactic Nuclei radiate over the electro-magnetic spectrum from radio waves to gamma rays. Understanding the physics of these objects therefore requires the synthesis of results from many different domains of Astronomy. It was the aim of the conference "Active Galactic Nuclei across the Electromagnetic Spectrum" to provide a forum where this exchange could take place. Some 300 astronomers participated to the conference, 250 of them presented results either as oral papers or in the form of posters. Observations in all domains of the electro magnetic spectrum in which astronomical observations can be made from the ground or from space were presented. Many theoretical contributions were also given. There has been a tremendous growth in the number and quality of Astronomical obser vations in many spectral domains over the past several years. Students of Active Galactic Nuclei have been particularly keen to make use of the available facilities (both space born and on the ground), often in a very organised way, in order to obtain repeated simultane ous data covering large bands of the spectrum. This approach has produced a qualitatively new set of data for understanding the physics of Active Galactic Nuclei. The task of the meeting was to review this data in a coherent way.

Active Galactic Nuclei

Active Galactic Nuclei
Author: Volker Beckmann
Publisher: John Wiley & Sons
Total Pages: 390
Release: 2013-08-29
Genre: Science
ISBN: 352766680X

Active Galactic Nuclei This AGN textbook gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy distribution will be discussed, pointing out what can be observed in different wavebands. The different physical models are presented together with formula important for the understanding of AGN physics. Furthermore, the authors discuss the AGN with respect to its environment, host galaxy, feedback in galaxies and in clusters of galaxies, variability, etc. and finally the cosmological evolution of the AGN phenomenon. This book includes phenomena based on new results in the X-Ray and gamma-ray domain from new telescopes such as Chandra, XMM-Newton, the Fermi Gamma-Ray Space Telescope, and the VHE regime not mentioned so far in AGN books. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. From the contents: The observational picture of AGN Radiative processes The central engine AGN types and unification AGN through the electromagnetic spectrum AGN variability Environment Quasars and cosmology Formation, evolution and the ultimate fate of AGN What we do not know (yet)

Multiwavelength Observations of Clusters of Galaxies and the Role of Cluster Mergers

Multiwavelength Observations of Clusters of Galaxies and the Role of Cluster Mergers
Author:
Publisher:
Total Pages:
Release: 2000
Genre:
ISBN:

Some clusters of galaxies have been identified as powerful sources of non-thermal radiation, from the radio to X-ray wavelengths. The classical models proposed for the explanation of this radiation usually require large energy densities in cosmic rays in the intracluster medium and magnetic fields much lower than those measured using the Faraday rotation. They study here the role that mergers of clusters of galaxies may play in the generation of the non-thermal radiation, and they seek for additional observable consequences of the model. They find that if hard X-rays and radio radiation are respectively interpreted as inverse Compton scattering (ICS) and synchrotron emission of relativistic electrons, large gamma ray fluxes are produced, and for the Coma cluster, where upper limits are available, these limits are exceeded. They also discuss an alternative and testable model that naturally solves the problems mentioned above.