Download or read book Nuclear Activity in Nearby Galaxies written by Mercedes Esteves Filho and published by . This book was released on 2003 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mass Transfer Induced Activity in Galaxies written by Isaac Shlosman and published by Cambridge University Press. This book was released on 2003-10-30 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: How gas flows and starbursts light up active galaxies.
Download or read book Interactions of Galaxies and Their Nuclear Activity written by Oved Avi Dahari and published by . This book was released on 1984 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Activity in a Volume limited Sample of Nearby Galaxies written by Paulina Lira and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Activity in a Volume limited Sample of Nearby Galaxies written by Paulina Lira and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Interplay Among Black Holes Stars and ISM in Galactic Nuclei IAU S222 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2004 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: How massive are the largest and smallest nuclear black holes in galaxies? Why are the masses of nuclear black holes proportional to those of their host galaxy bulges? How is nuclear activity triggered? What are the observational signatures of such processes? What are the connections between the active nucleus, stars and interstellar medium in galaxies? Answers to these questions are addressed in this book, which presents a compilation of 191 works covering recent observations from X-rays to radio wavelengths, as well as theoretical modeling of accretion disks, stellar populations and galaxy and black hole evolution. This volume presents the nuclear activity as a phase in the life of a galaxy, which is intimately connected to the evolution of its stars and interstellar medium. It brings together recent developments in topics covering most aspects of galaxy evolution, and is a valuable resource for astronomers and graduate students working in extragalactic astronomy.
Download or read book Observational Evidence of Activity in Galaxies written by E.Ye. Khachikian and published by Springer. This book was released on 1987-05-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: IAU Symposium No. 121 was hosted by the Byurakan Astrophysical Observatory in Soviet Armenia, almost 30 years after Ambartsumian's pioneering ideas about galaxy activity were first published and almost exactly 20 years after the first Byurakan IAU symposium on nuclear activity (No. 29, "Non-stable Phenomena in Galaxies, May 1966). Although the proceedings of the first Byurakan symposium were not published in English, that conference provided a definitive impulse to the field, as Ambartsumian's ideas had done 10 years earlier. The Byurakan Astrophysical Observatory was thus a particularly appropriate setting for IAU 121. The symposium was also very timely since many new exciting results were presented which will surely revolutionize many of our present ideas about nuclear activity in galaxies and QSO's. The first results of the by now famous Markarian survey were presented by B.E. Markarian in the first Byurakan conference. Unfortunately, his untimely death prevented him from attending the second conference, but the influence of his fundamental work was certainly felt.
Download or read book Active Galactic Nuclei written by Francoise Combes and published by John Wiley & Sons. This book was released on 2022-09-21 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: All galaxies host a super-massive black hole in their center. These black holes grow their mass in symbiosis with their host galaxy and moderate their star formation. When matter is driven towards the nucleus, an accretion disk is formed to transfer angular momentum and considerable energy is released when the material falls into the black hole: this is the phenomenon of active galactic nuclei (AGN). A nucleus can shine one thousand times more brightly than the entire galaxy with its 200 billion stars. The nuclear activity can take many forms, from very powerful quasars to more ordinary Seyfert galaxies, passing by radio-galaxies, which eject a collimated plasma at ten times the radius of the galaxy. This book examines all of these manifestations and presents a unified view. When two galaxies merge, a binary black hole is formed and the two black holes will spiral inwards and merge, emitting long gravitational waves, which could be detected by the future LISA satellite.
Download or read book The Nuclear Region Host Galaxy and Environment of Active Galaxies written by Erika Benítez and published by Instituto de Astronomia Universidad Nacional Autonoma de Mex. This book was released on 2008 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Influence of Galaxy Interactions on Nuclear Activity written by Roc M. Cutri and published by . This book was released on 1986 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Influence of Nuclear Activity Onto the Morphology of Galaxies written by Arman Khalatyan and published by . This book was released on 2007 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Towards a Complete Census of Active Galactic Nuclei in the Nearby Universe written by Andrew Goulding and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As it is well established that almost all galaxies host a central supermassive black hole (SMBH), it is natural to ask, how many of these SMBHs are actively accreting? Studies aimed at answering this question can better define the fraction of nearby galaxies that harbour active galactic nuclei (AGNs), provide constraints on the growth of local SMBHs, and further our understanding towards the connection between AGN activity and galaxy evolution. In the first part of this thesis, we use high-quality mid-infrared (IR) spectroscopy to investigate the ubiquity of AGN activity in a complete volume-limited sample of nearby galaxies to D15 Mpc. We present analyses based on the detection of high-excitation emission lines to unambiguously identify AGNs in even the most heavily dust-obscured and gas-rich galaxies. We find that almost half of the AGN population are not identified in large-scale optical surveys, most likely due to strong circumnuclear star-formation activity and/or extinction through the host galaxy. In the second part of this thesis, we use sensitive hard X-ray (2-10 keV) and mid-IR constraints to calculate bolometric luminosities of these D15 Mpc AGNs and combine these luminosities with well-constrained SMBH masses to estimate relative mass accretion rates. We use these data to calculate the volume-average SMBH growth rate of galaxies in the local Universe and find that AGNs hosting SMBHs with M_BH ~ 10 6-10 7 M_o are dominated by optically unidentified AGNs. These relatively small SMBHs are acquiring a significant proportion of their mass in the present-day and are amongst the most rapidly growing in the local Universe. In the third part of this thesis, we using [NeV]3427A as an unambiguous indicator of AGN activity to assess the incidence of AGNs in a statistically significant galaxy sample derived from the Sloan Digital Sky Survey (SDSS). On the basis of [NeV], we find strong empirical evidence that the theoretical maximum starburst limit provides a good identification threshold for AGNs. However, we find that only ~27% of Seyfert galaxies have strong detections of [NeV]3427A in their optical spectroscopy. Using spectral stacking analyses we determine that the lack of high-ionisation emission line signatures are due to poor spectral sensitivity and/or high levels of dust extinction. In the final part of this thesis, we use a suite of mid-IR, optical and X-ray luminosity indicators to search for Compton-thick AGNs at z~0.03-0.2, a region of parameter space which is currently poorly constrained by deep narrow-field X-ray surveys. We use the XMM-Newton serendipity survey and the SDSS to select a sample of 14 candidate Compton-thick AGNs. On the basis of the optical [OIII], mid-IR [OIV] and 6um AGN continuum luminosities we conservatively find that the X-ray emission in almost half of our sample appear to be attenuated by a factor15, i.e., they are likely to be obscured by Compton-thick material with N_H 1.5 x 10 24 cm -2. Under the reasonable assumption that our 14 AGNs are representative of the overall X-ray undetected AGN population in the SDSS-XMM parent sample, we estimate that>20% of the optical Type-2 AGN population are likely to be obscured by Compton-thick material. These Compton-thick AGNs identified in our sample harbour some of the most rapidly growing SMBHs in the nearby Universe. Overall, the techniques and results presented in this thesis have arguably provided the most complete and unambiguous census of AGN activity in nearby galaxies to date.
Download or read book The stellar content of the nuclei of nearby galaxies written by Hyron Spinrad and published by . This book was released on 1971 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Resolving Black Hole and Star Formation Activity in Nearby Galaxies written by Mallory Elyse Molina and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Black hole accretion and star formation exhibit different properties with observed spatial scale. To fully understand them, we must consider the local environment's impact on measured global properties. My dissertation focuses on the spatially resolved excitation mechanisms that power observed emission, and the dust that obscures it. Low ionization nuclear emission regions (LINERs) are common in nearby galaxies, and are often explained by photoionization by low luminosity active galactic nuclei (AGNs). But this energy source is not sufficient to power the observed emission lines that define LINERs on 100 pc scales. Using the Hubble Space Telescope, I resolved the nuclear regions of three nearby LINERs on the 10 pc scale to track the dominant power source with distance from the nucleus. The resulting physical model involved photoionization from the AGN within the central 20 pc, and shock excitation at larger distances. I conclude that integrated LINER-like emission can be explained by a combination of photoionization by the AGN and shocks on different spatial scales.The advancement and cessation of star formation within a galaxy is vital for understanding galaxy evolution. Furthermore, the rest-frame ultra violet (UV) and optical bands are crucial for disentangling the star formation history, metallicity and age of systems. To that end, I construct a data set of 150 galaxies with Swift Ultra Violet Optical Telescope (UVOT) UV photometry and Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at Apache Point Observatory (SDSS-IV/MaNGA) optical IFU spectroscopy. I present properties of the data set, and use it to quantify relations between the UV and H-alpha star formation rate proxies.Unfortunately, our understanding of star formation is highly dependent on dust attenuation, which itself depends on the spatial scales and properties on which it is observed. This is especially true in the UV band, where the attenuation laws from literature differ dramatically. Therefore, any attempts to understand star formation histories in using the Swift+MaNGA data catalog will be subject to this systematic. To address this, I studied the attenuation law of kiloparsec-sized star forming regions using a subset of 29 galaxies. I compared the attenuation from the individual regions with that of the parent galaxy, and find the attenuation of the optical nebular emission is similar between the two physical scales, but that of the UV stellar continuum is not. I attribute this difference to sightline-dependencies of the stellar continuum attenuation and dilution of the UV light by older stars.Through spatially resolved studies of black hole accretion and star formation activity in nearby galaxies, my dissertation work provides context for the integrated properties of nearby galaxies, and provides context for future statistical surveys.
Download or read book Physics of Active Galactic Nuclei at all Scales written by Danielle Alloin and published by Springer. This book was released on 2006-09-07 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains a collection of lecture notes written by recognized experts in the field of Active Galactic Nuclei (AGN). The collection is aimed at providing both an introduction and at the same time an overview of the state-of-the-art of AGN research. This book also addresses the still not entirely understood link of an AGN with its host galaxy and also the related question of the birth and growth of massive black holes in the Universe.
Download or read book Faint Nuclear Activity in Early type Galaxies written by D.A. Baxter and published by . This book was released on 1991 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics and Interactions of Galaxies written by Roland Wielen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress towards an understanding of the dynamics and interactions of galaxies has been spurred on more than ever by a wealth of new observations and numerical experiments. The Heidelberg Conference 1989, the papers of which are collected in this volume, was extremely successful in presenting a synoptic view of the field in all its aspects: galaxy interactions in the early universe and in recent times, interactions of our galaxy and its neighbours, dynamical problems of elliptical and disk galaxies, groups and clusters, starburst and nuclear activity triggered by interactions, merger scenarios, and numerical experiments. Researchers and graduate students, specialists or not, will find here a complete overview of a rapidly growing field of astronomy.
