Charting the stellar, dust and gas content of galaxies : a panchromatic view at the galaxy evolution across cosmic time PDF Download

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Category :
Languages : en
Pages : 0

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Author: Timothy Michael Weinzirl
Publisher:
ISBN: 9783319069609
Category :
Languages : en
Pages : 252

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Author: David A Williams
Publisher: Royal Society of Chemistry
ISBN: 1788019253
Category : Science
Languages : en
Pages : 167

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Without interstellar dust, the Universe as we see it today would not exist. Yet at first we considered this vital ingredient merely an irritating fog that prevented a clear view of the stars and nebulae in the Milky Way and other galaxies. We now know that interstellar dust has essential roles in the physics and chemistry of the formation of stars and planetary systems, the creation of the building blocks of life, and in the movement of those molecules to new planets. This is the story in this book. After introducing the materials this interstellar dust is made of, the authors explain the range of sizes and shapes of the dust grains in the Milky Way galaxy and the life cycle of dust, starting from the origins of dust grains in stellar explosions through to their turbulent destruction. Later on we see the variety of processes in interstellar space involving dust and the events there that cause the dust to change in ways that astronomers and astrobiologists can use to indirectly observe those events. This book is written for a general audience, concentrating on ideas rather than detailed mathematics and chemical formulae, and is the first time interstellar dust has been discussed at an accessible level.

Author: Maan H. Hani
Publisher:
ISBN:
Category :
Languages : en
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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.

Author: Caleb Ryan Choban
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Interstellar dust grains play prominent roles in physical processes across astronomical scales and affect all astronomical observations to varying degrees. However, our understanding of how dust evolves within galaxies and across cosmic time is incomplete. We investigate the dust life cycle and make predictions for the evolution of galactic dust populations across cosmic time by developing dust evolution models and integrating them into cosmological galaxy simulations. In Chapter 2, we present two separate dust evolution models coupled with the "Feedback In Realistic Environment" (FIRE) model for stellar feedback and ISM physics. These models incorporate the main mechanisms comprising the dust life cycle but differ in their treatment of dust chemical composition and gas-dust accretion based on recent, contrasting approaches in the galaxy formation community. We test and compare these models in an idealized Milky Way-mass galaxy and find that both produce reasonable galaxy-integrated dust populations and predict gas-dust accretion as the main dust growth mechanism. However, only a model that simultaneously incorporates a physically motivated gas-dust accretion routine and tracks the evolution of specific dust species can reproduce observed spatial dust variability within the Milky Way, in both amount and composition. In Chapter 3, we present a suite of cosmological galaxy simulations of Milky Way to dwarf halo-mass galaxies. These simulations utilize the dust evolution model presented in Chapter 2, which tracks the evolution of specific dust species and incorporates a physically motivated dust growth routine. We find that gas-dust accretion is the dominant producer of dust mass for all but the most metal-poor galaxies and, in the case of the Milky Way, dominates for the majority of the galaxy's life.We also discover that the onset of rapid growth via gas-dust accretion differs between dust species, arising from differences in element abundances, dust physical properties, and life cycles. These differences can explain the variable dust population, in both amount and composition, in the MW, LMC, and SMC and highlight the importance of accurate gas-dust accretion modeling for individual dust species.

Author: Andrea Cimatti
Publisher:
ISBN: 1108770525
Category : Science
Languages : en
Pages : 588

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A comprehensive examination of nearly fourteen billion years of galaxy formation and evolution, from primordial gas to present-day galaxies.

Author: D.C.B Whittet
Publisher: CRC Press
ISBN: 9780750306249
Category : Science
Languages : en
Pages : 414

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Book Description
Dust is a ubiquitous feature of the cosmos, impinging directly or indirectly on most fields of modern astronomy and astrophysics. Dust in the Galactic Environment, Second Edition provides a thorough overview of the subject, covering general concepts, methods of investigation, important results and their significance, relevant literature, and some suggestions for promising avenues of future research. Since the publication of the first edition of this popular graduate text, major advances have been made in our understanding of astrophysical dust, especially in the light of exciting new results from space- and ground-based telescopes, together with advances in laboratory astrophysics and theoretical modeling. This new, expanded edition highlights the latest results and provides a context for future research opportunities. The first chapter provides a historical perspective for current research and an overview of interstellar environments and the role of dust in astrophysical processes, followed by a discussion of the cosmic history of the chemical elements expected to be present in dust and an examination of the effect of gas-dust interactions on gas phase abundances. The next several chapters describe the observed properties of interstellar grains, such as their extinction, polarization, absorption, and emission characteristics. Then, the book explores the origin and evolution of dust, tracing its life cycle in a succession of environments from circumstellar shells to diffuse interstellar clouds, molecular clouds, protostars, and protoplanetary disks. The final chapter summarizes progress toward a unified model. Dust in other galaxies is discussed as an integral part of the text rather than as a distinct topic requiring separate chapters. Containing extensive references and problems to aid understanding and illustrate basic principles, the book is ideally suited for graduate and advanced undergraduate courses. It will also be an invaluable reference for postgraduate students and researchers working in this important field.

Author: Andreas Zezas
Publisher: Cambridge University Press
ISBN: 1316877523
Category : Science
Languages : en
Pages : 318

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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.

Author: José M. Vilchez
Publisher: Springer Science & Business Media
ISBN: 9401733139
Category : Science
Languages : en
Pages : 556

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Galaxies have a history. This has become clear from recent sky surveys showing that distant galaxies, formed early in the life of the Universe, differ from the nearby ones. This book contains the proceedings of a 2000 conference addressing observational clues in this area.

Author: C. Chiosi
Publisher: Springer Science & Business Media
ISBN: 9400945981
Category : Science
Languages : en
Pages : 481

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As it was said by one of the participants to this workshop" In our attempts to understand the spectral evolution of galaxies, we are fortunate indeed to have the ability to look back in time and observe galaxies as they were billions of years ago. Perhaos in no other discipline is it possible to gain such a direct view to hJstory. The galaxies we seek to study are remote, their light faint, and thus only recently has it become technicaJlv feasible to sample the spectra of normal luminosity galaxies at lookback times of five billion years or more" .... or, perhaps. even to see galaxies in the process of their formation. or shortly afterwards. This fourth workshop organized by the "Advanced School ot Astronomy was indeed centered on the "Spectral Evolution of Galaxies". on reviewing and discussing the relevant astrophysical processes and on assessing our current ability to model and understand the evolution of stellar populations. Following an opening session dealing with some outstanding questions of galaxy evolution. Session I addressed the specific problems of galaxy and star formation processes. topics of uncertainty and controversy to which IRAS observations may give novel perspectives. The properties of stellar populations in the local group of galaxies formed the basis of Session II. Session III dealt with the fundaments of the theory of spectral and photometrical evolution of stellar populations. and with recent developments in the theory of stellar structure. a necessary step to model and understand galactic evolution.