Download or read book Multiwavelength Selection and Study of BL Lacertae Objects written by Richard Matthew Plotkin and published by . This book was released on 2009 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Multiwavelength Study of BL Lacertae Objects written by Travis Arthur Rector and published by . This book was released on 1998 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi wavelength Studies of BL Lacertae Objects written by Eric Steven Perlman and published by . This book was released on 1994 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi Wavelength Observations of the High peaked BL Lacertae Objects 1ES 1011 496 and 1ES 2344 514 written by Stefan Rügamer and published by . This book was released on 2013 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Multiwavelength Variability and Optical Microvariability Investigations of X ray and Radio Selected Blazars written by Margaret Angela Osterman and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The extreme AGN known as blazars can be classified based on their spectral properties into X-ray and radio selected objects, known as XBLs and RBLs, respectively. In this work, the results of new multiwavelength campaigns are presented for two XBLs and two RBLs. Each campaign contains simultaneous observations in the radio, optical, and X-ray regimes. A campaign on a third RBL was completed using near-simultaneous archival radio, optical/IR, and gamma-ray data. The simultaneous multiwavelength behavior exhibited in each campaign was analyzed by examining the multiwavelength variability and using spectral analysis. Observations of prominent optical microvariability were quantitatively analyzed. Previously published results for other blazars were compared to the new and archival results. Many interesting results emerged from these investigations. PG 1553+11, a radio-weak blazar, was found to be an extreme XBL. During three campaigns performed for the XBL PKS 2155-304, different variability behavior was observed each time. In a high flux state, the X-ray behavior was strongly correlated with the optical behavior. In a weak state, the X-ray and optical behaviors were not correlated. In an intermediate state, the X-ray behavior was somewhat correlated with the optical behavior. CTA 102, an RBL, exhibited some of the most extreme optical microvariability ever observed, including a brightening of about 0.07 magnitudes in less than 15 minutes. Surprisingly, the optical spectra of RBLs CTA 102, PKS 1622-297, and 3C 345 were found to become redder when in a brighter flux state. The RBLs all exhibited large amplitude optical microvariability. The campaigns on PG 1553+11, CTA 102, and PKS 1622-297 were the first simultaneous multiwavelength campaigns performed for these objects. For objects in which the results of at least two campaigns were available, including PKS 2155-304, correlations that appeared to be present at one epoch seemed to vanish at other times. The SSC model represented many of the observations well. Color studies of the selected BL Lac objects found them to be bluer when brighter, while the selected FSRQs were found to be redder when brighter. These results provide strong motivation for future multiwavelength campaigns that provide broader wavelength and more extensive temporal coverage.

Download or read book Population Studies of Radio and X ray Selected BL Lacertae Objects written by Mario João M. Marchã and published by . This book was released on 1991 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Variability of Blazars written by E. VALTAOJA (Ed) and published by Cambridge University Press. This book was released on 1992 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: Blazars (also known as BL Lac objects), first discovered in 1978, are unusually energetic objects in the extragalactic universe. About 200 are known or suspected. They are radio sources with highly variable optical and radio emission, as well as high polarisation, and their optical spectra normally have no distinguishable features. It is generally accepted that they belong to that class of galaxies with active galactic nuclei, which are presumed to be driven by infall of matter to a supermassive black hole. In this book researchers give a complete summary of the observations of blazars and the theoretical interpretation. A comprehensive listing of confirmed and candidate objects is included. Mechanisms in which the variability can arise from shocks and relativistic jets are discussed. There are at least four different answers given to the question: what is a blazar? This book is a complete overview of the violent activity observed in these extreme active galactic nuclei.

Download or read book Optically Identified BL Lacertae Objects From the Sloan Digital Sky Survey written by and published by . This book was released on 2005 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a sample of 386 BL Lacertae candidates identified from 2860 deg(exp 2) of the Sloan Digital Sky Survey (SDSS) spectroscopic database. The candidates are primarily selected to have quasi-featureless optical spectra and low proper motions as measured from SDSS and USNO-B positions; however, our ability to separate Galactic from extragalactic quasi-featureless objects (QFOs) on the basis of proper motion alone is limited by the lack of reliable proper motion measurements for faint objects. Fortunately, high proper motion QFOs, mostly DC white dwarfs, populate a well-defined region of color space, approximately corresponding to blackbodies with temperatures in the range 7000-12,000 K. QFOs with measurable redshifts or X-ray or radio counterparts (i.e., evidence of an extragalactic/ active galactic nucleus nature) loosely follow a track in color space that corresponds to power-law continua plus host galaxy starlight, with typical power-law slopes in the range 1

Download or read book Multiwavelength Approach to Unidentified Gamma Ray Sources written by K.S. Cheng and published by Springer Science & Business Media. This book was released on 2005-05-02 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nearly one half of the point-like gamma-ray sources detected by EGRET instrument of the late Compton satellite are still defeating our attempts at identifying them. To establish the origin and nature of these enigmatic sources has become a major problem of current high-energy astrophysics. The second workshop on Multiwavelength Approach to Unidentified Gamma-ray Sources intends to shed new and fresh light on the problem of the nature of these mysterious sources and the objects behind them. The proceedings contain 46 contributed papers in this subject, which cover theoretical models on gamma-ray sources as well as the best multiwavelength strategies for the identification of the promising candidates. The topics of this conference also include energetic phenomena ocurring both in galactic and extragalactic scenarios, phenomena that might lead to the appearance of what we have called high-energy unidentified sources. The book will be of interest for all active researchers in the high-energy astrophysics and related research areas as well as for scientists and graduate students interested in understanding the recent progress in this field.

Download or read book Accretion Power in Astrophysics written by Juhan Frank and published by Cambridge University Press. This book was released on 2002-01-17 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accretion Power in Astrophysics examines accretion as a source of energy in both binary star systems containing compact objects, and in active galactic nuclei. Assuming a basic knowledge of physics, the authors describe the physical processes at work in accretion discs and other accretion flows. The first three chapters explain why accretion is a source of energy, and then present the gas dynamics and plasma concepts necessary for astrophysical applications. The next three chapters then develop accretion in stellar systems, including accretion onto compact objects. Further chapters give extensive treatment of accretion in active galactic nuclei, and describe thick accretion discs. A new chapter discusses recently discovered accretion flow solutions. The third edition is greatly expanded and thoroughly updated. New material includes a detailed treatment of disc instabilities, irradiated discs, disc warping, and general accretion flows. The treatment is suitable for advanced undergraduates, graduate students and researchers.

Download or read book BL Lac Phenomenon written by Leo O. Takalo and published by . This book was released on 1999 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Blazar Variablility Workshop II written by Hugh Richard Miller and published by . This book was released on 2006 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi Wavelength Continuum Emission of AGN written by International Astronomical Union. Symposium and published by Springer. This book was released on 1994-04-30 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: (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

Download or read book Variability of Active Galactic Nuclei written by and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1993 with total page 1146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of the Radio and X ray Properties of BL Lacertae Objects written by Antonios G. Polatidis and published by . This book was released on 1989 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi Wavelength Continuum Emission of AGN written by International Astronomical Union. Symposium and published by Springer. This book was released on 1994-04-30 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: (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