Download or read book Active Galactic Nuclei Mergers and Outflows written by Robert Scott Barrows and published by . This book was released on 2013 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: I have investigated the nature of a subset of active galactic nuclei (AGN) which show double peaks in their characteristic optical and ultraviolet emission lines. I have performed this investigation through studies of the broad emission line regions (BLRs), which are produced less than 1 pc from the central supermassive black hole (SMBH), and the narrow emission line regions (NLRs), which originate at larger (kpc) distances. The BLR studies consist of detailed line modeling of two individual quasars with double-peaked broad emission line profiles. The modeling suggests there are two primary interpretations of the complex broad line profiles. The first possiblity is line emission from the surface of an asymmetric and/or non-uniform accretion disk of a low-accretion rate AGN; these sources are known as double-peaked emitters and account for only about 3% of the quasar population. The second possibility is line emission from the BLRs of two actively accreting SMBHs in a close (

Download or read book The Physics and Evolution of Active Galactic Nuclei written by Hagai Netzer and published by Cambridge University Press. This book was released on 2013-09-16 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive introduction to the theory underpinning our study of active galactic nuclei and the ways we observe them.

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 Dissecting Merging Galaxies Using Integral Field Spectroscopy written by Elise Jasmin Hampton and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies grow through the accretion of gas, minor mergers and major mergers in the hierarchical picture of galaxy evolution. The merging of two gas-rich galaxies cause gas to be driven towards the centres of the individual galaxies producing intense circum-nuclear star formation and creating a fuel reservoir for the accretion onto the central blackhole. Feedback due to supernova winds or AGN (Active Galactic Nuclei) accretion blows out the surrounding gas through an outflow at later merger stages, that may be large enough to deplete the galaxies of their fuel reservoir and hence shut down star formation and starve the central black hole. It is still uncertain what the impact of outflows is on merging galaxies, and when in the merging process they are most significant. This thesis has used Integral Field Spectroscopy (IFS) observations of merging galaxies to probe the impact of outflows on gas-rich major mergers. Using velocity-resolved absorption and emission lines arising from the interstellar medium of the galaxies, this thesis shows that the occurrence of outflows increases with merger stage and also that these outflows are not caused by the same physical processes, such as star formation or an AGN, in each merger system. This thesis describes the machine learning algorithm created to expedite the decision making process of multi-component emission line fitting for studies of ionised gas in large IFS surveys. The remainder of the research outlined in this thesis has identified a number of new facts about merging galaxies that are important for further research in this field including the following; Composite galaxies are being incorrectly classed as the same type of galaxy when they can range in excitation mechanisms; Composite galaxies are not the same between different morphologies, including between merging galaxies and isolated galaxies; The outflow from the northern nucleus of the merging system IRAS F10257- 4339 can be traced in neutral, ionised, and molecular gas, and is most likely caused by starformation; Outflows of neutral gas from galaxies increases with merger stage.

Download or read book Properties and Impact of Active Galactic Nuclei driven Outflows Through Cosmic Time written by Gene Chun Kwan Leung and published by . This book was released on 2020 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation studies the properties of outflows driven by active galactic nuclei (AGNs) and their impact on the evolution of galaxies. AGNs are predicted by theoretical models of galaxy formation to provide the necessary feedback to produce realistic galaxies. In theoretical models, AGNs provide feedback by driving outflows that remove gas from the host galaxy, thereby quenching star formation in massive galaxies and producing scaling relations between supermassive black holes and galaxies. Despite being indispensable in theory, critical open questions remain for AGN-driven outflows from an observational perspective. This dissertation first presents two studies using data from the MOSDEF survey, a large spectroscopic survey of galaxies when the Universe was about 3.5 billions years old (z~2). The first study focuses on the incidence and physical properties of AGN-driven outflows at z~2. We show that AGN-drive outflows are at least as prevalent at z~2 as they are in the local Universe. They are fast and extend to distances comparable to the size of the host galaxy. Using emission line ratio diagnostics, we find our data consistent with the picture of negative AGN feedback, where AGN-driven outflows suppress star formation, and find no evidence of galaxy-wide positive AGN feedback. The second study focuses on the demographics of galaxies hosting AGN-driven outflows and the relation between outflow properties and the galaxy and AGN population at z~2. We show that AGN-driven outflows are a ubiquitous phenomenon occurring across the galaxy population and in different phases of galaxy evolution, both before and after quenching. By measuring the energetics and correlations of AGN-driven outflows, we find that the outflows are more energetic at z~2 than in the local Universe, where AGNs are more powerful on average. We find that the outflows remove gas at a rate comparable to or faster than gas is being converted into stars. This shows that AGN-driven outflows at z~2 are capable of regulating star formation in the host galaxy. The third study in this dissertation presents integral field spectroscopy of a nearby ultraluminous infrared galaxy (ULIRG) and AGN Mrk 273. The study focuses on the extended ionized gas on scales of ~20 kpc. We detect for the first time highly ionized gas in one of the extended nebula surrounding the galaxy. From this, we show that shocks contribute significantly to the ionization of the gas in the extended nebulae, mixed with AGN photoionization. Our data is compatible with theoretical models in which AGNs drive a multiphase outflow, and slower-moving extended cold gas filaments form out of a more spatially confined but faster warm outflow. Our data suggests that AGNs play an important role in ejecting gas in the ULIRG phase of galaxy evolution.

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 Mass Outflow in Active Galactic Nuclei written by D. Michael Crenshaw and published by . This book was released on 2002 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Proceedings of a March 2001 workshop held in Washington, D.C., bringing together an international group of researchers to share new developments in the field during the last four years. Fifty-seven contributions are arranged in sections on X-ray absorption and emission; intrinsic UV absorption; broad absorption-line QSOs; narrow- line region, broad-line region and jets; and kinematics and dynamical models. A sampling of topics: high-resolution X-ray spectroscopy of the warm gas in Seyfert 1 galaxies, observations of warm absorbers in AGN, radio-selected broad absorption line quasars, the importance of shocks in the ionization of the narrow line region of Seyferts, and strong shocks and supersonic winds in homogeneous media. Indexed by author and object, but not by subject. Annotation c. Book News, Inc., Portland, OR (booknews.com)

Download or read book Probing Galaxy Evolution Through Numerical Simulations written by Maan H. Hani and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Large observational surveys have compiled substantial galaxy samples with an array of different properties across cosmic time. While we have a broad understanding of how galaxies grow and build their observable properties, the details of galaxy growth and evolution pose a fundamental challenge to galaxy evolution theories. Nonetheless, galaxy evolution is ultimately regulated by the properties of the gas reservoir. In this thesis I use numerical simulations to answer key questions related to the galactic gas reservoir, and galaxy mergers: a major transformational process. In Chapter 2 I present an analysis of 28 simulated L* galaxies to understand the physical processes that shape the massive gas reservoir surrounding galaxies (i.e. the circum-galactic medium; CGM). I show that (1) the gas and metal content of the CGM is driven by galaxy growth and the strength/presence of feedback processes, and (2) the ionisation and internal structures of the CGM are shaped by galactic outflows, and active galactic nucleus luminosity. Albeit dependent on internal galactic properties and the physical processes that shape them, the CGM remains greatly diverse, thus posing a challenge for observational surveys. As a follow-up to my study of normal L* galaxy gas halos, in Chapter 3 I present a theoretical study of the effect of galaxy mergers on the CGM. I demonstrate that galaxy mergers can leave a strong imprint on the CGM's gas and metal content, metallicity, and size. The merger can increase (1) the CGM's metallicity by 0.2-0.3 dex within 0.5 Gyr post-merge, and (2) the metal covering fractions by factors of 2-3. In spite of the increase in the CGM's metal content, the hard ionising field during the merger can drive a decline in the covering fractions of commonly observed ions. In Chapter 4 I shift focus to star formation, particularly the effects of galaxy mergers on star formation. While the effects of galaxy mergers have been proven observationally, theoretical predictions are limited to small binary merger suites and cosmological zoom-in studies. I present a statistical study of 27,691 post-merger galaxies from IllustrisTNG to quantify the effect of galaxy mergers on galactic star formation. I report a dependence in the merger-induced star formation rate (SFR) on mass ratio, stellar mass, gas fraction, and galaxy SFR. I also track the evolution of the effects of galaxy mergers demonstrating their decay over ~500 Myr. In Chapter 6, I leverage galactic scaling relations to extend my work on the effects of galaxy mergers to resolved scales. However, before using the simulated resolved scaling relations, I first examine their existence and robustness. In Chapter 5, I demonstrate the emergence of the kpc-scale star forming main sequence (rSFMS) in the FIRE-2 simulations. Nonetheless, the slope of the rSFMS is dependent on the (1) star formation tracer's timescale, and (2) observed resolution, which I propose is caused by the clumpiness of star formation. I develop a toy model that quantitatively captures the effects of clumpy star formation. I then illustrate how the model can be used to characterise the mass of star-forming clumps. Having demonstrated the existence and robustness of known scaling relations in numerical simulations, I explore the effects of galaxy mergers on resolved scales in Chapter 6. I generate synthetic observations for 1,927 post-mergers in IllustrisTNG and examine the radially-dependent merger-driven SFR enhancement, and metallicity suppression in post-mergers. Galaxy mergers preferentially boost star formation in the centres and suppress metallicities globally. The effects of the merger depends on galaxy properties such as stellar mass, SFR, mass ratio, and gas fraction.

Download or read book The Relationship Between Active Galactic Nuclei and Metal enriched Outflows in Galaxy Clusters written by Charles Kirkpatrick and published by . This book was released on 2012 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clusters of galaxies are host to powerful Active Galactic Nuclei (AGN) that greatly affect the thermal history of clusters. By keeping X-ray emitting gas from cooling, massive, run away star formation does not occur in the brightest cluster galaxy (BCG). This is achieved through radio jets displacing large quantities of metal-rich gas and carving out cavities in the intracluster medium (ICM). This metal-rich gas was originally formed within the BCG and ejected through type Ia supernovae. The current distribution of the ejecta suggests an extra source of energy has spread the material far out into the ICM. Currently, it is unclear what mechanisms are responsible. In this thesis, I present evidence, in the form of X-ray imaging and spectra, that establishes a link between AGN and the observed distribution of metal-rich gas. First, the BCG in the Abell 1664 cluster is unusually blue and is forming stars at a rate of ~23 solar masses per year. The BCG is located within 5 kpc of the X-ray peak, where the cooling time of 3.5x10^8 yr and entropy of 10.4 keV cm^2 are consistent with other star-forming BCGs in cooling flow clusters. The cooling rate in this region is roughly consistent with the star formation rate, suggesting that the hot gas is condensing onto the BCG. We use the scaling relations of Birzan et al. (2008) to show that the AGN is underpowered compared to the central X-ray cooling luminosity by roughly a factor of three. We suggest that A1664 is experiencing rapid cooling and star formation during a low-state of an AGN feedback cycle that regulates the rates of cooling and star formation. Modeling the emission as a single temperature plasma, we find that the metallicity peaks 100 kpc from the X-ray center, resulting in a central metallicity dip. However, a multi-temperature cooling flow model improves the fit to the X-ray emission and is able to recover the expected, centrally-peaked metallicity profile. Next, using deep Chandra observations of the Hydra A galaxy cluster, we examine the metallicity structure near the central galaxy and along its powerful radio source. We show that the metallicity of the ICM is enhanced by up to 0.2 dex along the radio jets and lobes compared to the metallicity of the undisturbed gas. The enhancements extend from a radius of 20 kpc from the central galaxy to a distance of ~120 kpc. We estimate the total iron mass that has been transported out of the central galaxy to be between 2E7 and 7E7 solar masses which represents 10% - 30% of the iron mass within the central galaxy. The energy required to lift this gas is roughly 1% to 5% of the total energetic output of the AGN. Evidently, Hydra A's powerful radio source is able to redistribute metal-enriched, low entropy gas throughout the core of the galaxy cluster. The short re-enrichment timescale

Download or read book Two phase Models of Disk Driven Outflows in Active Galactic Nuclei with Combined Hydromagnetic and Radiative Driving written by John Eric Everett 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 Active Galactic Nuclei written by John Edward Dyson and published by Manchester University Press. This book was released on 1985 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Phenomenology of Outflows from Radio Loud Active Galactic Nuclei written by Erick Jimenez Guerra and published by . This book was released on 1997 with total page 252 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 The Evolution of Active Galactic Nuclei in Galaxy Clusters and Correlation with Mergers written by and published by . This book was released on 2010 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Merger driven Fueling of Active Galactic Nuclei written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dual active galactic nuclei (AGNs) and offset AGNs are kpc-scale separation supermassive black holes pairs created during galaxy mergers, where both or one of the black holes are AGNs, respectively. These dual and offset AGNs are valuable probes of the link between mergers and AGNs but are challenging to identify. Here we present Chandra/ACIS observations of 12 optically selected dual AGN candidates at $z\lt 0.34$, where we use the X-rays to identify AGNs. We also present Hubble Space Telescope/Wide Field Camera 3 observations of 10 of these candidates, which reveal any stellar bulges accompanying the AGNs. We discover a dual AGN system with separation ${\rm \Delta }x=2.2$ kpc, where the two stellar bulges have coincident [O iii] [lambda]5007 and X-ray sources. This system is an extremely minor merger (460:1) that may include a dwarf galaxy hosting an intermediate mass black hole. We also find six single AGNs, and five systems that are either dual or offset AGNs with separations ${\rm \Delta }x\lt 10$ kpc. Four of the six dual AGNs and dual/offset AGNs are in ongoing major mergers, and these AGNs are 10 times more luminous, on average, than the single AGNs in our sample. This hints that major mergers may preferentially trigger higher luminosity AGNs. Further, we find that confirmed dual AGNs have hard X-ray luminosities that are half of those of single AGNs at fixed [O III] [lambda]5007 luminosity, on average. Lastly, this could be explained by high densities of gas funneled to galaxy centers during mergers, and emphasizes the need for deeper X-ray observations of dual AGN candidates.

Download or read book QSO Absorption Lines written by J. Chris Blades and published by Cambridge University Press. This book was released on 1988-08-18 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second title in the series published for the Space Telescope Science Institute researches the current models of quasar absorption and the systems of absorption lines in the spectra of quasars. Experts in this field discuss the nature of the absorbing process in the vicinity of quasars, the "Lyman-alpha forest", metal-line systems, and quasars as probes of high redshift galaxies. The Hubble Space Telescope will be a valuable tool for learning more about the physics and astronomy of quasars.

Download or read book Outflow and Accretion Physics in Active Galactic Nuclei written by Sean Michael McGraw and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: