Agn Feedback In Galaxy Formation
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Agn Feedback In Galaxy Formation
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Author : Vincenzo Antonuccio-Delogu
language : en
Publisher: Cambridge University Press
Release Date : 2010-10-28
Agn Feedback In Galaxy Formation written by Vincenzo Antonuccio-Delogu and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-10-28 with Science categories.
During the past decade, convincing evidence has been accumulated concerning the effect of active galactic nuclei (AGN) activity on the internal and external environment of their host galaxies. Featuring contributions from well-respected researchers in the field, and bringing together work by specialists in both galaxy formation and AGN, this volume addresses a number of key questions about AGN feedback in the context of galaxy formation. The topics covered include downsizing and star-formation time scales in massive elliptical galaxies, the connection between the epochs of supermassive black hole growth and galaxy formation and the question of whether AGN and star formation coexist. Authors also discuss key challenging computational problems, including jet-interstellar/intergalactic medium interactions, and both jet- and merging-induced star formation. Suitable for researchers and graduate students in astrophysics, this volume reflects the engaging and lively discussions taking place in this emerging field of research.
Properties And Impact Of Active Galactic Nuclei Driven Outflows Through Cosmic Time
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Author : Gene Chun Kwan Leung
language : en
Publisher:
Release Date : 2020
Properties And Impact Of Active Galactic Nuclei Driven Outflows Through Cosmic Time written by Gene Chun Kwan Leung and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
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.
Exploring The Effect Of Active Galactic Nuclei On Quenching Morphological Transformation And Gas Flows With Simulations Of Galaxy Evolution
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Author : Ryan Brennan
language : en
Publisher:
Release Date : 2017
Exploring The Effect Of Active Galactic Nuclei On Quenching Morphological Transformation And Gas Flows With Simulations Of Galaxy Evolution written by Ryan Brennan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Galaxies categories.
We study the evolution of simulated galaxies in the presence of feedback from active galactic nuclei (AGN). First, we present a study conducted with a semi-analytic model (SAM) of galaxy formation and evolution that includes prescriptions for bulge growth and AGN feedback due to galaxy mergers and disk instabilities. We find that with this physics included, our model is able to qualitatively reproduce a population of galaxies with the correct star-formation and morphological properties when compared with populations of observed galaxies out to z~3. We also examine the characteristic histories of galaxies with different star-formation and morphological properties in our model in order to draw conclusions about the histories of observed galaxies. Next, we examine the structural properties of galaxies (morphology, size, surface density) as a function of distance from the ``star-forming main sequence'' (SFMS), the observed correlation between the star formation rates (SFRs) and stellar masses of star-forming galaxies. We find that, for observed galaxies, as we move from galaxies above the SFMS (higher SFRs) to those below it (lower SFRs), there exists a nearly monotonic trend towards more bulge-dominated morphology, smaller radius, lower SFR density, and higher stellar density. We find qualitatively similar results for our model galaxies, again driven by our prescriptions for bulge growth and AGN feedback. Next, we conduct a study of the effect of AGN feedback on the gas in individual galaxies using a suite of cosmological hydrodynamical simulations. We compare two sets of 24 galaxies with halo masses of 10^12 - 10^13.4 Msun run with two different feedback models: one which includes stellar feedback via UV heating, stellar winds and supernovae, AGN feedback via momentum-driven winds and X-ray heating, and metal heating via photoelectric heating and cosmic X-ray background heating from accreting black holes in background galaxies (MrAGN), and another model which is identical except that it does not include any AGN feedback (NoAGN). We find that our AGN feedback prescription acts both ``ejectively, '' removing gas from galaxies in powerful outflows, and ``preventatively'', suppressing the inflow of gas onto the galaxy. The histories of MrAGN galaxies are gas ejection-dominated, while the histories of NoAGN galaxies are gas recycling-dominated. This difference in gas cycles results in the quenching of star formation in MrAGN galaxies, while their NoAGN counterparts continue to form stars until z=0. Finally, we examine how this change in the baryon cycle affects the metal content of MrAGN galaxies relative to NoAGN galaxies and find that a combination of gas removal from and metal injection into the hot gas halo results in higher average halo metallicities in MrAGN galaxies.
The Physics Of Galaxy Formation
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Author : Claudia Del P. Lagos
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-10-15
The Physics Of Galaxy Formation written by Claudia Del P. Lagos and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-10-15 with Science categories.
This thesis addresses two of the central processes which underpin the formation of galaxies: the formation of stars and the injection of energy into the interstellar medium from supernovae, called feedback. In her work Claudia Lagos has completely overhauled the treatment of these processes in simulations of galaxy formation. Her thesis makes two major breakthroughs, and represents the first major steps forward in these areas in more than a decade. Her work has enabled, for the first time, predictions to be made which can be compared against new observations which probe the neutral gas content of galaxies, opening up a completely novel way to constrain the models. The treatment of feedback from supernovae, and how this removes material from the interstellar medium, is also likely to have a lasting impact on the field. Claudia Lagos Ph.D. thesis was nominated by the Institute for Computational Cosmology at Durham University as an outstanding Ph.D. thesis 2012.
Constraining Star Formation Rates And Agn Feedback In High Z Radio Galaxies
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Author : Theresa Maria Falkendal
language : en
Publisher:
Release Date : 2018
Constraining Star Formation Rates And Agn Feedback In High Z Radio Galaxies written by Theresa Maria Falkendal and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
The evolution of galaxies is something that is still not well understood. The cosmic star formation rate density peaks between 1
Galaxy Evolution And Feedback Across Different Environments Iau S359
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Author : Thaisa Storchi Bergmann
language : en
Publisher: Cambridge University Press
Release Date : 2021-02-28
Galaxy Evolution And Feedback Across Different Environments Iau S359 written by Thaisa Storchi Bergmann and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-02-28 with Science categories.
The goal of IAU Symposium 359 on 'Galaxy Evolution and Feedback across Different Environments' (GALFEED) was to bring together the active galactic nuclei (AGN) and galaxy evolution scientific communities. The AGN phase occurs in most galaxies and critically influences their evolution, so it is important to study the two processes together and for researchers, in both topics, to learn from one another. They ask key questions such as: How do galaxies acquire their gas and how efficiently is it transformed into stars? How is the supermassive black hole in a galaxy center fuelled to become an AGN? What is the main physical mechanism that quenches star formation? How powerful are the stellar and AGN feedback processes in regulating galaxy evolution? And what is the role of the environment on galaxy evolution and AGN triggering? Astronomers engage in these discussions spanning from early galaxies to the present day.
Active Galactic Nuclei
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Author : Volker Beckmann
language : en
Publisher: John Wiley & Sons
Release Date : 2013-08-29
Active Galactic Nuclei written by Volker Beckmann and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-08-29 with Science categories.
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)
Galaxy Formation And Mergers With Stars And Massive Black Holes
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Author : Chi-hun Kim
language : en
Publisher: Stanford University
Release Date : 2011
Galaxy Formation And Mergers With Stars And Massive Black Holes written by Chi-hun Kim and has been published by Stanford University this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
While mounting observational evidence suggests the coevolution of galaxies and their embedded massive black holes (MBHs), a comprehensive astrophysical understanding which incorporates both galaxies and MBHs has been missing. To tackle the nonlinear processes of galaxy formation, we develop a state-of-the-art numerical framework which self-consistently models the interplay between galactic components: dark matter, gas, stars, and MBHs. Utilizing this physically motivated tool, we present an investigation of a massive star-forming galaxy hosting a slowly growing MBH in a cosmological LCDM simulation. The MBH feedback heats the surrounding gas and locally suppresses star formation in the galactic inner core. In simulations of merging galaxies, the high-resolution adaptive mesh allows us to observe widespread starbursts via shock-induced star formation, and the interplay between the galaxies and their embedding medium. Fast growing MBHs in merging galaxies drive more frequent and powerful jets creating sizable bubbles at the galactic centers. We conclude that the interaction between the interstellar gas, stars and MBHs is critical in understanding the star formation history, black hole accretion history, and cosmological evolution of galaxies. Expanding upon our extensive experience in galactic simulations, we are well poised to apply this tool to other challenging, yet highly rewarding tasks in contemporary astrophysics, such as high-redshift quasar formation.
Gas Accretion Onto Galaxies
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Author : Andrew Fox
language : en
Publisher: Springer
Release Date : 2017-03-23
Gas Accretion Onto Galaxies written by Andrew Fox and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-03-23 with Science categories.
This edited volume presents the current state of gas accretion studies from both observational and theoretical perspectives, and charts our progress towards answering the fundamental yet elusive question of how galaxies get their gas. Understanding how galaxies form and evolve has been a central focus in astronomy for over a century. These studies have accelerated in the new millennium, driven by two key advances: the establishment of a firm concordance cosmological model that provides the backbone on which galaxies form and grow, and the recognition that galaxies grow not in isolation but within a “cosmic ecosystem” that includes the vast reservoir of gas filling intergalactic space. This latter aspect in which galaxies continually exchange matter with the intergalactic medium via inflows and outflows has been dubbed the “baryon cycle”. The topic of this book is directly related to the baryon cycle, in particular its least well constrained aspect, namely gas accretion. Accretion is a rare area of astrophysics in which the basic theoretical predictions are established, but the observations have been as yet unable to verify the expectations. Accretion has long been seen around the Milky Way in so-called High Velocity Clouds, but detecting accretion even around nearby galaxies has proved challenging; its multi-phase nature requires sensitive observations across the electromagnetic spectrum for full characterization. A promising approach involves looking for kinematic signatures, but accretion signatures are often confused with internal motions within galaxies. Accretion studies therefore touch a wide range of astrophysical processes, and hence a wide cross-section of the astronomical community. As observational facilities are finally able to access the wavelength ranges and depths at which accretion processes may be manifest, the time is right to survey these multiple lines of investigation and determine the state of the field in accretion studies of the baryon cycle.
Regulation Of Star Formation Amidst Heating And Cooling In Galaxies And Galaxy Clusters
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Author : Sravani Vaddi
language : en
Publisher:
Release Date : 2016
Regulation Of Star Formation Amidst Heating And Cooling In Galaxies And Galaxy Clusters written by Sravani Vaddi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Galaxies categories.
"Galaxy clusters are the largest gravitationally bound systems in the Universe and often host the largest galaxies (known as the brightest cluster galaxies (BCG)) at its centers. These BCG’s are embedded in hot 1-10 keV X-ray gas. A subset of galaxy clusters known as cool-core clusters show sharply peaked X-ray emission and high central densities, demonstrating cooling of the surrounding halo gas in timescales much shorter than a Hubble time. These observations led to the development of a simple cooling flow model. In the absence of an external heating process, a cooling flow model predicts that the hot intracluster medium gas in these dense cores would hydrostatically cool, generating cooling flows in the center of the cluster. This cooled gas will eventually collapse to form stars and contribute to the bulk of galaxy mass. The rates of star formation actually observed in the clusters however are far less than predicted by the cooling flow model, suggesting a non-gravitational heating source. Active galactic nuclei (AGN), galaxies hosting a supermassive black hole that ejects outflows via accretion, is currently the leading heating mechanism (referred to as AGN feedback) explaining the observed deficit in the star formation rates. AGN feedback also offers an elegant explanation to the observed black hole and galaxy co- evolution. Much of the evidence for AGN feedback has been obtained from studies focussed on galaxy clusters and luminous massive systems with little evidence that it occurs in more typical systems in the local universe. Our research investigates this less explored area to address the importance of AGN heating in the regulation of star formation in typical early type galaxies in the local universe. We selected a sample of 200+ early type, low redshift galaxies and carried out a multiple wavelength study using archival observed in the UV, IR and radio. Our results suggest that early type galaxies in the current epoch are rarely powerful AGN and AGN feedback is constrained to be low in our sample of low redshift, typical early type galaxies. Although heating from the AGN is powerful enough to suppress the cooling of the hot gas, it does not completely offset gas cooling at all times and substantial cooler gas exists in the cores of some galaxy clusters (cool-core clusters), the gas properties of which are not explained by AGN heating models alone. The second part of our research focuses on unravelling the mystery of the unknown heating source regulating star formation in galaxy clusters. We have obtained deep FUV spectroscopy using the HST cosmic origins spectrograph of two cool-core clusters A2597 and Zw3146. FUV spectral lines provide the much needed diagnostics capable of discriminating between various heating models, which was difficult with the standard optical line diagnostics. We investigate several heating/ionization mechanisms namely stellar photoionization, AGN photoionization, and shock heating. We use pre-run Mappings III photoionization code results to model the ionizing radiation field. In general, we notice that there is no one single model that provides a satisfactory explanation for the ionization state of gas. How- ever, we show that stellar and AGN photoionization alone are not enough to ionize the nebula in A2597 and speculate that, shock heating is the likely ionizing source."--Abstract.