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The Effect Of Galaxy Interactions On Star Formation And Agn Activity At 05
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Book Synopsis The Effect of Galaxy Interactions on Star Formation and AGN Activity at 0:5 by : Ekta Arjunkumar Shah
Download or read book The Effect of Galaxy Interactions on Star Formation and AGN Activity at 0:5 written by Ekta Arjunkumar Shah and published by . This book was released on 2021 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Galaxy interactions and mergers play an important role in the hierarchical formation and evolution of galaxies. Studies in the nearby universe show a higher star formation rate (SFR) and active galactic nuclei (AGN) fraction in interacting and merging galaxies than in their isolated counterparts, indicating that such interactions are important contributors to star formation and black hole growth. A large fraction of massive galaxies is thought to be affected by galaxy mergers at high redshifts because the galaxy merger rate increases with redshift. We use deep observations and cosmological simulations to study the role of galaxy mergers and interactions in enhancing SFR and AGN activity in galaxies at $0.5 z 3.0$, covering the peak of cosmic star formation and AGN activity ($z\sim2$). For the observational study, we use deep CANDELS and COSMOS observations to compile the largest known sample of major spectroscopic galaxy pairs (2381 with $V
Book Synopsis The Star Formation and Merger Evolution of Interacting Galaxies by : Carrie Ruth Bridge
Download or read book The Star Formation and Merger Evolution of Interacting Galaxies written by Carrie Ruth Bridge and published by . This book was released on 2007 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hierarchical models and observations show that galaxy mergers and interactions play a key role in galaxy assembly and star formation, but to what extent is still unclear. This thesis attempts to quantify their contribution to galaxy evolution by probing the number of interactions and mergers, along with their star forming properties as a function of redshift. The presence of long tidal tails and bridges are robust signatures of recent merger activity. This completely dynamical phenomenon was used to develop a new classification scheme to identify interacting galaxies and probe the interaction fraction and merger rate. We applied this new technique to large area, multi-band imaging obtained via the Canada France Hawaii Telescope Legacy Survey (CFHTLS-Deep), yielding the first statistically secure, lower limit of the galaxy interaction fraction between 0.1 z 1.0. Optically, the fraction of galaxies undergoing an interaction evolves moderately with redshift as (1 + z)2.24+/-0.24The Spitzer 24mum coverage of both the Extragalactic First Look Survey (XFLS) and CFHTLSDeep Survey were used to carry out one of the first and largest merger studies of IR bright galaxies. Within the ACS component of the XFLS, interactions were identified over the full merger sequence using traditional techniques, finding a merger rate increase for 24microm galaxies of (1 + z) & sim;2. This result implies that merging is an increasingly important process in the evolution of luminous IR galaxies (LIRGs), contributing 40--60% of the IR luminosity density and at least 30--40% of the star formation rate density at z & sim; 1. Galaxy interactions at all stages are found to have elevated star formation rates greater than a factor of two-four (on average) and a higher incidence of AGN activity compared to non-interacting field galaxies. This result supports a causal connection between galaxy merging, induced star formation, and AGN activity. Ultimately, major mergers provide a moderate contribution to the evolution of the cosmic star formation rate density and IR luminosity density to z & sim; 1, with an increasing trend suggesting that merging plays a larger role at higher redshifts (z 1). It is also clear that merging plays a significant role in triggering the processes that power the IR emission of LIRG galaxies at z 0.5.
Book Synopsis Exploring the Interplay Between Star Formation and Active Galactic Nuclei and the Role of Environment in Galaxy Evolution by : Jonathan Florez
Download or read book Exploring the Interplay Between Star Formation and Active Galactic Nuclei and the Role of Environment in Galaxy Evolution written by Jonathan Florez and published by . This book was released on 2021 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Book Synopsis The Effects of Galaxy Interactions on Star Formation by : Bradley Wayne Peterson
Download or read book The Effects of Galaxy Interactions on Star Formation written by Bradley Wayne Peterson and published by . This book was released on 2011 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Understanding Star Formation and AGN Activity at Z~2-3 by : Kevin Nicholas Hainline
Download or read book Understanding Star Formation and AGN Activity at Z~2-3 written by Kevin Nicholas Hainline and published by . This book was released on 2012 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is compelling evidence that the growth of supermassive black holes and the stellar populations of their host galaxies are intricately linked. At the same time, the exact relationship between the buildup of stellar mass and the growth of supermassive black holes is still not well understood. At z ~ 2, both star-formation and Active Galactic Nuclei (AGN) activity in the universe were at peak levels, and this epoch is ideal for exploring the coevolution of stars and supermassive black holes. This dissertation examines high-redshift galaxies, looking at the particular properties of star-forming galaxies, the stellar populations of AGNs and the relationship between black hole and star-formation activity at z ~ 2 - 3. I have used the magnification afforded by gravitational lensing of z ~ 2 star-forming galaxies to measure important physical properties of the stars and gas in these galaxies. Using near-IR spectroscopy, I have calculated the metallicities, ionization parameters, star-formation rates, and dynamical masses for two galaxies which help to explain the differences between local- and high-redshift star-forming galaxies. The third and fourth chapters of this work cover the analysis of a sample of z ~ 2 - 3 AGNs drawn from the UV-selected Lyman Break Galaxy (LBG) survey. I present a rest-frame UV composite spectrum for this sample of AGNs. This spectrum shows many emission and absorption features, such as HI Lyman-alpha, NV1240, NIV]1483,1486, CIV1548,1550, HeII1640, and CIII]1907,1909. Redshifted SiIV1394 absorption provides evidence for outflowing high-ionization gas in these objects at speeds of 10^3 km/s. Finally, by using optical, near-IR, and mid-IR photometry, which covers the rest-frame UV to near-IR portions of the galaxies spectral energy distributions, I have modeled the SEDs of the AGNs that comprise this sample. I have developed a unique dual-component modeling approach that allows me to correct for the presence of an AGN. Based on these results, I have explored the relationship in the host galaxy between AGN activity, maturity of the stellar population, and regulation of star formation.
Book Synopsis Using WISE to Find Obscured AGN Activity in SDSS Mergers and Interactions by : Madalyn Elizabeth Weston
Download or read book Using WISE to Find Obscured AGN Activity in SDSS Mergers and Interactions written by Madalyn Elizabeth Weston and published by . This book was released on 2015 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: In simulations, major encounters between gas-rich galaxies are predicted to drive gas to the centers of interacting and merging systems triggering new star formation (SF) and fueling an active galactic nucleus (AGN). Depending on the rate of SF, large amounts of obscuring dust can make detection of merger-induced activity difficult and may be at the heart of the ongoing merger-AGN connection debate. To provide better constraints on the importance of obscured AGNs, we use data from the Wide-field Infrared Survey Explorer (WISE) for a comprehensive sample of over 1000 major galaxy interactions and ongoing mergers visually selected from the SDSS with 1010 M¤ and 0.01
Download or read book Star Formation in Galaxies written by and published by . This book was released on 1987 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Star-Formation Rates of Galaxies by : Andreas Zezas
Download or read book Star-Formation Rates of Galaxies written by Andreas Zezas and published by Cambridge University Press. This book was released on 2021-04-29 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Star-formation is one of the key processes that shape the current state and evolution of galaxies. This volume provides a comprehensive presentation of the different methods used to measure the intensity of recent or on-going star-forming activity in galaxies, discussing their advantages and complications in detail. It includes a thorough overview of the theoretical underpinnings of star-formation rate indicators, including topics such as stellar evolution and stellar spectra, the stellar initial mass function, and the physical conditions in the interstellar medium. The authors bring together in one place detailed and comparative discussions of traditional and new star-formation rate indicators, star-formation rate measurements in different spatial scales, and comparisons of star-formation rate indicators probing different stellar populations, along with the corresponding theoretical background. This is a useful reference for students and researchers working in the field of extragalactic astrophysics and studying star-formation in local and higher-redshift galaxies.
Book Synopsis Star Formation and Feedback in Simulations of Interacting Galaxies by : Thomas J. Cox
Download or read book Star Formation and Feedback in Simulations of Interacting Galaxies written by Thomas J. Cox and published by . This book was released on 2004 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Robert C. Kennicutt Jr. Publisher :Springer Science & Business Media ISBN 13 :3540316302 Total Pages :417 pages Book Rating :4.5/5 (43 download)
Book Synopsis Galaxies: Interactions and Induced Star Formation by : Robert C. Kennicutt Jr.
Download or read book Galaxies: Interactions and Induced Star Formation written by Robert C. Kennicutt Jr. and published by Springer Science & Business Media. This book was released on 2006-04-18 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the written versions of the lectures given at the 26th course of the renowned Saas-Fee series. The book represents a comprehensive and up-to-date review of the field of galaxy interaction. Nowadays, galaxies are no longer seen as immutable objects: they evolve, interact, merge, blaze, and reshape. Dynamic forces can induce powerful stellar activity able to transform the matter composition and morphology of galaxies. The lectures included in this book aim at a better understanding of these remarkable and fascinating phenomena. Though the book is intended for graduate students and young post-docs in astrophysics, it contains more advanced and original material, as well as historical perspectives, which will be of great interest to experts and astronomy teachers also.
Book Synopsis Outskirts of Galaxies by : Johan H. Knapen
Download or read book Outskirts of Galaxies written by Johan H. Knapen and published by Springer. This book was released on 2017-07-09 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of invited reviews written by world-renowned experts on the subject of the outskirts of galaxies, an upcoming field which has been understudied so far. These regions are faint and hard to observe, yet hide a tremendous amount of information on the origin and early evolution of galaxies. They thus allow astronomers to address some of the most topical problems, such as gaseous and satellite accretion, radial migration, and merging. The book is published in conjunction with the celebration of the end of the four-year DAGAL project, an EU-funded initial training network, and with a major international conference on the topic held in March 2016 in Toledo. It thus reflects not only the views of the experts, but also the scientific discussions and progress achieved during the project and the meeting. The reviews in the book describe the most modern observations of the outer regions of our own Galaxy, and of galaxies in the local and high-redshift Universe. They tackle disks, haloes, streams, and accretion as observed through deep imaging and spectroscopy, and guide the reader through the various formation and evolution scenarios for galaxies. The reviews focus on the major open questions in the field, and explore how they can be tackled in the future. This book provides a unique entry point into the field for graduate students and non-specialists, and serves as a reference work for researchers in this exciting new field.
Book Synopsis Studying the AGN-merger Connection Through Visual Classification of CANDELS Galaxies by : Christina T. Magagnoli
Download or read book Studying the AGN-merger Connection Through Visual Classification of CANDELS Galaxies written by Christina T. Magagnoli and published by . This book was released on 2020 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Mergers play a vital role in galaxy evolution, having the potential to trigger Active Galactic Nucleus (AGN) activity, star formation, or changes in morphology. In this work, we investigate whether galaxy mergers have an effect on AGN activity in the galaxies involved. We used a visual classification scheme to classify the morphologies of nearly 50,000 galaxies and identify galaxy mergers in the CANDELS fields, a Multi-Cycle Treasury Program using the Hubble Space Telescope. We use IR and X-ray selection criteria to identify IR and X-ray AGN, and matched controls to both our AGN subsample and merger subsample. We investigated the fraction of mergers that host AGN, as well as the fraction of AGN that are found in merging systems, to study the AGN-merger connection from multiple angles. We also investigated the properties of mergers, such as the mass ratios of early-stage mergers, and their star forming properties. We find that galaxies involved in a merger or interaction are more likely than non-merging galaxies to host AGN. The fraction of merging systems that host AGN is 0.034±0.002,compared to an AGN fraction of 0.023±0.001 in non-merging systems. We also find that IR AGN are more likely to be found in merging systems, with a merger fraction of 0.353+0.021−0.019, compared to a merger fraction of 0.225+0.007−0.006 in control galaxies without AGN activity. This is likely because these are more dusty and obscured, and are expected to be observed earlier in the merger process, when merger signatures are more visible. The AGN detected in either the X-ray or both the IR and X-ray are even less likely to be found in merging systems, as the merger signatures are expected to fade later in the merging process. These results show that mergers play an important role in driving AGN activity."--Abstract.
Book Synopsis Star Formation and AGN Activity in Distant Massive Galaxies by : Pece Podigachoski
Download or read book Star Formation and AGN Activity in Distant Massive Galaxies written by Pece Podigachoski and published by . This book was released on 2016 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Galactic Bulges by : Eija Laurikainen
Download or read book Galactic Bulges written by Eija Laurikainen and published by Springer. This book was released on 2015-09-29 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of invited reviews on Galactic Bulges written by experts in the field. A central point of the book is that, while in the standard picture of galaxy formation a significant amount of the baryonic mass is expected to reside in classical bulges, the question what is the fraction of galaxies with no classical bulges in the local Universe has remained open. The most spectacular example of a galaxy with no significant classical bulge is the Milky Way. The reviews of this book attempt to clarify the role of the various types of bulges during the mass build-up of galaxies, based on morphology, kinematics and stellar populations and connecting their properties at low and high redshifts. The observed properties are compared with the predictions of the theoretical models, accounting for the many physical processes leading to the central mass concentration and their destruction in galaxies. This book serves as an entry point for PhD students and non-specialists and as a reference work for researchers in the field.
Book Synopsis Galaxy Formation and Mergers with Stars and Massive Black Holes by : Chi-hun Kim
Download or read book Galaxy Formation and Mergers with Stars and Massive Black Holes written by Chi-hun Kim and published by Stanford University. This book was released on 2011 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Constraining the Evolution of Galaxies Over the Interaction Sequence with Multiwavelength Observations and Simulations by : Lauranne Lanz
Download or read book Constraining the Evolution of Galaxies Over the Interaction Sequence with Multiwavelength Observations and Simulations written by Lauranne Lanz and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interactions are crucial for galaxy formation and profoundly affect their evolution. However, our understanding of the impact of interactions on star formation and activity of the central supermassive black hole remains incomplete. In the canonical picture of the interaction process, these processes are expected to undergo a strong enhancement, but some recent studies have not found this prediction to be true in a statistically meaningful sense. This thesis uses a sample of local interactions observed from the ultraviolet to the far-infrared and a suite of N-body hydrodynamic simulations of interactions to examine the evolution of star formation, stellar mass, dust properties, and spectral energy distributions (SEDs) over the interaction sequence.
Book Synopsis Secular Evolution of Galaxies by : Jesús Falcón-Barroso
Download or read book Secular Evolution of Galaxies written by Jesús Falcón-Barroso and published by Cambridge University Press. This book was released on 2012 with total page 657 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation and evolution of galaxies is one of the most important topics in modern astrophysics. Secular evolution refers to the relatively slow dynamical evolution due to internal processes induced by a galaxy's spiral arms, bars, galactic winds, black holes and dark matter haloes. It plays an important role in the evolution of spiral galaxies with major consequences for galactic bulges, the transfer of angular momentum, and the distribution of a galaxy's constituent stars, gas and dust. This internal evolution is in turn the key to understanding and testing cosmological models of galaxy formation and evolution. Based on the twenty-third Winter School of the Canary Islands Institute of Astrophysics, this volume presents reviews from nine world-renowned experts on the observational and theoretical research into secular processes, and what these processes can tell us about the structure and formation of galaxies. The volume provides a firm grounding for graduate students and early career researchers working on galactic dynamics and galaxy evolution.
