The Relationship Between Active Galactic Nuclei and the Star-forming Properties of Their Host Galaxies PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download The Relationship Between Active Galactic Nuclei and the Star-forming Properties of Their Host Galaxies PDF full book. Access full book title The Relationship Between Active Galactic Nuclei and the Star-forming Properties of Their Host Galaxies by E. P. W. Bernhard. Download full books in PDF and EPUB format.
Author: E. P. W. Bernhard
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: E. P. W. Bernhard
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Isaac Shlosman
Publisher: Cambridge University Press
ISBN: 9780521543309
Category : Science
Languages : en
Pages : 534
Get Book Here
Book Description
How gas flows and starbursts light up active galaxies.
Author: Mojegan Azadi
Publisher:
ISBN:
Category :
Languages : en
Pages : 209
Get Book Here
Book Description
In this dissertation we study the properties of active galactic nuclei (AGN), which are powered by the accretion activity of supermassive black holes residing at the centers of galaxies. While observations propose that growth of AGN and galaxies are globally tied, we investigate whether this connection exists in individual galaxies. We also investigate various AGN selection techniques and star formation rate (SFR) estimates using multi-wavelength data from Chandra, Spitzer and rest-frame optical spectra from the Keck telescope. We find that combining multi-wavelength identification techniques provides a more complete AGN sample, as each selection method suffers from selection biases. In particular, all selection techniques are biased against identifying AGN in lower mass galaxies. Once stellar mass selection biases are taken into account, we find that AGN reside in galaxies with similar physical properties (i.e., SFR) as inactive galaxies. We find that while AGN are prevalent in both star-forming and quiescent galaxies, AGN of a given accretion rate are more likely to reside in star-forming galaxies. The probability of fueling an AGN does not strongly depend on SFR for a star-forming galaxy, though it decreases when star formation is shut down in quiescent galaxies. We also find no evidence for a strong correlation between SFR or stellar mass of the host galaxy and AGN luminosity. These results indicate that while both AGN and galaxy growth are reliant on the same fuel, enhanced star formation activity does not necessarily go hand-in-hand with increased AGN activity. While the star formation activity of galaxies can be traced with various indicators, our investigations indicate that extrapolations from mid-infrared data using calibrations based on local galaxies overestimates SFRs at higher redshift. We show that a combination of mid-infrared and far-infrared data provide a more reliable SFR estimation than the mid-infrared data alone. We also find that the robustness of UV-based SFRs depends on the extinction correction method used. We find a relatively small fraction of z ∼ 2 galaxies have SFRs from infrared observations that are elevated relative to other SFR tracers, and we do not find any contribution from AGN in this excess.
Author: Volker Beckmann
Publisher: John Wiley & Sons
ISBN: 352766680X
Category : Science
Languages : en
Pages : 390
Get Book Here
Book Description
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)
Author: Gene Chun Kwan Leung
Publisher:
ISBN:
Category :
Languages : en
Pages : 193
Get Book Here
Book Description
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.
Author: Bradley M. Peterson
Publisher: Cambridge University Press
ISBN: 9780521479110
Category : Science
Languages : en
Pages : 258
Get Book Here
Book Description
How can we test if a supermassive black hole lies at the heart of every active galactic nucleus? What are LINERS, BL Lacs, N galaxies, broad-line radio galaxies and radio-quiet quasars and how do they compare? This timely textbook answers these questions in a clear, comprehensive and self-contained introduction to active galactic nuclei - for graduate students in astronomy and physics. The study of AGN is one of the most dynamic areas of contemporary astronomy, involving one fifth of all research astronomers. This textbook provides a systematic review of the observed properties of AGN across the entire electromagnetic spectrum, examines the underlying physics, and shows how the brightest AGN, quasars, can be used to probe the farthest reaches of the Universe. This book serves as both an entry point to the research literature and as a valuable reference for researchers in the field.
Author: Jonathan Florez
Publisher:
ISBN:
Category :
Languages : en
Pages : 432
Get Book Here
Book Description
One of the central goals of extragalactic astronomy is to understand how galaxies grow their stellar mass and central black holes, the connection between star formation and active galactic nuclei (AGN), and the impact of environment on this growth. In this thesis, I utilize multiwavelength surveys that are both deep and wide, advanced computational codes that model the spectral energy distributions of galaxies with and without AGN, as well as state-of-the-art simulations of galaxy evolution in order to explore how galaxy properties are impacted by their surrounding environment and AGN activity. These studies explore galaxies over a redshift range of 0.015 z 0.023 (lookback time of ~ 0.2 to ~ 0.3 Gyr), and over a redshift range of 0.5 z 3.0 (lookback time of ~ 5 to ~ 12 Gyr). The large-area surveys used here provide some of the largest and most statistically robust samples to-date of rare massive galaxies (with stellar mass M [subscript *] 1011 M☉) and extremely luminous AGN (with X-ray luminosity L [subscript X] 1044 erg s−1) out to z ~ 3, thereby limiting the effects of cosmic variance and Poisson statistics. I analyze the observed stellar masses and star formation rates of galaxies as a function of environment and AGN activity, compare the empirical results to theoretical models of galaxy evolution, and discuss the implications of such comparisons. This work will provide significant guidance and constraints to the future development of theoretical models of galaxy growth. In Chapter 2 (Florez et al. 2021, ApJ, 906, 97) I measure the environmental dependence, where environment is defined by the distance to the third nearest neighbor, of multiple galaxy properties inside the Environmental COntext (ECO) catalog. I focus primarily on void galaxies at redshifts z = 0.015 - 0.023, which I define as the 10% of galaxies having the lowest local density. I compare the properties of void and non-void galaxies: baryonic mass, color, fractional stellar mass growth rate (FSMGR), morphology, and gas-to-stellar-mass ratio. The void galaxies typically have lower baryonic masses than galaxies in denser environments, and they display the properties expected of a lower mass population: they have more late-types, are bluer, have higher FSMGR, and are more gas rich. I also control for baryonic mass and investigate the extent to which void galaxies are different at fixed mass. I find that void galaxies are bluer, more gas-rich, and more star forming at fixed mass than non-void galaxies, which is a possible signature of galaxy assembly bias and other environmental processes. Furthermore, I show that these trends persist even at fixed mass and morphology, and I find that voids host a distinct population of early-types that are bluer and more star-forming than the typical red and quenched early-types. In addition to these empirical observational results, I also present theoretical results from mock catalogs with built-in galaxy assembly bias. I show that a simple matching of galaxy properties to (sub)halo properties, such as mass and age, can recover the observed environmental trends in the local galaxy population. In Chapter 3 (Florez et al. 2020, MNRAS, 497, 3273) I investigate the relation between AGN and star formation activity at 0.5 z 3 by analyzing 898 galaxies with high X-ray luminosity AGN (L [subscript X] 1044 erg s−1) and a large comparison sample of ~ 320,000 galaxies without such AGN. My samples are selected from a large (11.8 deg2) area in Stripe 82 that has multi-wavelength (X-ray to far-IR) data. The enormous comoving volume (~ 0.3 Gpc3) at 0.5
Author: Francoise Combes
Publisher: John Wiley & Sons
ISBN: 178945087X
Category : Science
Languages : en
Pages : 324
Get Book Here
Book Description
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.
Author: Christopher Mark Harrison
Publisher: Springer
ISBN: 3319284541
Category : Science
Languages : en
Pages : 208
Get Book Here
Book Description
This prize-winning Ph.D. thesis by Chris Harrison adopts a multi-faceted approach to address the lack of decisive observational evidence, utilising large observational data sets from several world-leading telescopes. Developing several novel observational techniques, Harrison demonstrated that energetic winds driven by Active Galactic Nuclei (AGN) are found in a large number of galaxies, with properties in agreement with model predictions. One of the key unsolved problems in astrophysics is understanding the influence of AGN, the sites of growing supermassive black holes, on the evolution of galaxies. Leading theoretical models predict that AGN drive energetic winds into galaxies, regulating the formation of stars. However, until now, we have lacked the decisive observational evidence to confirm or refute these key predictions. Careful selection of targets allowed Harrison, to reliably place these detailed observations into the context of the overall galaxy population. However, in disagreement with the model predictions, Harrison showed that AGN have little global effect on star formation in galaxies. Theoretical models are now left with the challenge of explaining these results.
Author: Xavier Barcons
Publisher: Cambridge University Press
ISBN: 9780521416511
Category : Nature
Languages : en
Pages : 328
Get Book Here
Book Description
A review of the current observational knowledge and understanding of the cosmic X-ray background.
