Low Ionization Nuclear Emission Line Regions

Low Ionization Nuclear Emission Line Regions
Author: Rachel Dudik (George Mason University graduate)
Publisher:
Total Pages: 217
Release: 2007
Genre: Active galaxies
ISBN:

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"The horizon of the universe, once thought to extend only to the disk of the Milky Way, is now known to embrace a host of diverse galaxies, from active galaxies such as quasars and Seyfert galaxies to normal galaxies such as our own. The recent discovery that virtually all local galaxies harbor massive nuclear black holes, has provided convincing evidence that active galactic nuclei (AGNs) and normal galaxies are indeed connected. The nature of this connection and the evolutionary history connecting them, however, continues to be elusive. Low Ionization Nuclear Emission-line Regions (LINERs) are the dominant population of 'active' galaxies in our local universe and may indeed be the missing piece to the evolutionary puzzle. LINERs are dened by optical line ratios uncharacteristic of photoionization by normal main sequence stars. While classical AGNs represent at most a few percent of the galaxy population, LINERs constitute as much as 50% of the total local extragalactic population. However, despite several decades of intense research, the ionization mechanism responsible for the unusual LINER spectrum remains a mystery. What is the ionization mechanism responsible for the empirical line ratios characteristic of LINER galaxies? How do LINERs t into the overall evolution of galaxies as we know it? Are LINERs a subclass of AGN? What is the evolutionary connection, if any, between galaxies with heavy starburst activity and AGNs? The majority of LINERs are dust enshrouded and therefore very luminous in the far-infrared. The far-infrared (far-IR) luminosity to the luminosity in the optical Bband (center = 4400A), the so-called IR-brightness ratio, can be used as a gauge of the amount of dust in host galaxy. LINERs span a wide range of LFIR/LB ratios, tending predominantly toward the IR-bright end. However, the majority of research to-date has been based on optically selected samples which are partial toward IR-faint LINERs. This bias toward IR-faint galaxies could have important consequences on statistical analyses which examine the fraction of LINERs hosting AGNs. In order for an accurate picture of LINERs to emerge, IR-bright as well as IR-faint galaxies must be studied. What fraction of IR-bright LINERs are AGNs? In light of the open questions regarding these remarkable objects, the central goal of this dissertation is to carry out a systematic multi-wavelength X-ray imaging and Infrared spectroscopic survey of nearby LINERs spanning a wide range of IRbrightness ratios in order to 1) characterize the dominant energy source responsible for their optical line ratios, 2) compare the AGN detection rate in our infrared selected sample with the optically selected samples, 3) determine the luminosities, spectral characteristics and accretion properties of the AGN-LINERs and compare them with the standard active galaxies, and nally, 4) relate the host galaxies properties to the properties of the central source in an attempt to constrain the role of LINERs in galaxy evolution and formation models"--Abstract.

Galaxies in Turmoil

Galaxies in Turmoil
Author: C. R. Kitchin
Publisher: Springer Science & Business Media
Total Pages: 302
Release: 2007-11-27
Genre: Science
ISBN: 1846286719

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Astronomers' Universe Series is a new series aimed at active amateur astronomers but is appropriate to a wider audience of astronomically-informed readers. The book provides an up-to-date account of active galaxies. Lists of such objects and their visual and imaged appearance in commercially available telescopes are an important component of this book. The book makes sense of the chaotic and apparently innumerable types of violently active galaxies. It provides the data and teaches the skills needed for users of small telescopes to observe and image some of these "galaxies in turmoil" for themselves.

The Nearest Active Galaxies

The Nearest Active Galaxies
Author: J. E. Beckman
Publisher: Editorial CSIC - CSIC Press
Total Pages: 320
Release: 1993
Genre: Active galaxies
ISBN: 9788400057114

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Astrophysics Of Gas Nebulae and Active Galactic Nuclei

Astrophysics Of Gas Nebulae and Active Galactic Nuclei
Author: Donald E. Osterbrock
Publisher: University Science Books
Total Pages: 488
Release: 2006
Genre: Science
ISBN: 9781891389344

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Thoroughly revised and expanded throughout, the new edition is a graduate-level text and reference book on gaseous nebulae, nova and supernova remnants. Much of the new data and new images are from the Hubble Space Telescope with two wholly new chapters being added along with other new features. The previous edition which was tried and tested for thirty years has now been succeeded by a revised, updated, larger edition, which will be valuable to anyone seriously interested in astrophysics.

Astrophysics of the Diffuse Universe

Astrophysics of the Diffuse Universe
Author: Michael A. Dopita
Publisher: Springer Science & Business Media
Total Pages: 445
Release: 2013-06-29
Genre: Science
ISBN: 3662058669

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The reference work on astrophysics to provide a comprehensive introduction to the physics of Interstellar Matter. The objective of the book is to show how physics can be applied to the understanding and diagnosis of the phase structure, the physical conditions and the chemical make-up and evolution of the interstellar medium. Unlike other textbooks in the field, here a more systematic approach has been adopted based on the authors' lecture course experience. It is aimed primarily at those undertaking post-graduate courses, or those doing advanced projects as part of honours undergraduate courses in physics or astrophysics.

Astronomy and Astrophysics Abstracts

Astronomy and Astrophysics Abstracts
Author: S. Böhme
Publisher: Springer Science & Business Media
Total Pages: 930
Release: 2013-12-14
Genre: Science
ISBN: 3662123401

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Astronomy and Astrophysics Abstracts aims to present a comprehensive documen tation of the literature concerning all aspects of astronomy, astrophysics, and their border fields. It is devoted to the recording, summarizing, and indexing of the relevant publications throughout the world. Astronomy and Astrophysics Abstracts is prepared by a special department of the Astronomisches Rechen-Institut under the auspices of the International Astronomical Union. Volume 34 records literature published in 1983 and received before February 17, 1984. Some older documents which we received late and which are not surveyed in earlier volumes are included too. We acknowledge with thanks contributions of our colleagues all over the world. We also express our gratitude to all organiza tions, observatories, and publishers which provide us with complimentary copies of their publications. Starting with Volume 33, all the recording, correction, and data processing work was done by means of computers. The recording was done by our technical staff members Ms. Helga Ballmann, Ms. Mona El-Choura and Ms. Monika Kohl. Mr. Martin Schlotelburg and Mr. Ulrich Oberall supported our task by careful proofreading. It is a pleasure to thank them all for their encouragement. Heidelberg, March 1984 The Editors Contents Introduction . . . . . . . . . . . . Concordance Relation: ICSU-AB-AAA 3 Abbreviations 10 Periodicals, Proceedings, Books, Activities 001 Periodicals . . . . . . . . . . . 15 002 Bibliographical Publications, Documentation, Catalogues, Atlases 50 003 Books ...... . 58 004 History of Astronomy 67 005 Biography . . 71 006 Personal Notes 73 007 Obituaries . . .