Download or read book Characterizing the Interstellar and Circumgalactic Medium in Distant Star Forming Galaxies written by Xinnan Du and published by . This book was released on 2018 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rest-frame ultraviolet (UV) and optical spectroscopy provides valuable information on the physical properties of the neutral and ionized interstellar medium (ISM) in star-forming galaxies. Such observations probe both the systemic interstellar component originating from H II regions, and the multi-phase outflowing component that is associated with star-formation feedback and can ultimately contribute to the circumgalactic and even intergalactic medium (CGM and IGM, respectively). In this dissertation, I investigate the physical properties of ionized gas in star-forming regions, and the kinematics and evolution of the multi-phase outflowing ISM/CGM in distant star-forming galaxies spanning the redshift range z ~ 1-4. This work consists of three studies that examine different aspects of the ISM and CGM, which collectively improve our understanding of the gas content in galaxies and the processes associated with the formation of massive stars near the peak of the star-formation-rate (SFR) density in the universe. I present a comparison of kinematics between the low- and high-ionization absorption features at z ~ 1, and demonstrate that the apparent larger blueshift of interstellar C IV relative to the low-ionization features is likely a result from the nature of resonant transitions instead of an evidence of the faster motion of the highly ionized gas. I further investigate the origin of the highly ionized gas by examining the correlations between the spectral properties of C IV and various galaxy properties. Both the blueshift and equivalent width (EW) of C IV are modulated by SFR and specific SFR, suggesting a direct connection between the highly ionized gas and the formation of massive stars. Nebular emission features provide valuable insights into the physical conditions of the ionized gas in H II regions, as well as the properties of young, massive stars. I show that the nebular C III] emission at z ~ 1 is much weaker compared to the detections from galaxies observed during the epoch of reionization (z > 6), and explore the factors that modulate the strength of this nebular feature. In combination with the results from photoionization models, I further infer the gas-phase metallicity and abundance pattern in the z ~ 1 star-forming galaxies based on the observed rest-frame C III] EW. Studying the lower-redshift analogs of the z > 6 C III] emitters is an alternative way to obtain more detailed information on the physical properties of these extreme-emission-line-galaxies (EELGs). By assembling a sample of EELGs at z ~ 1-2 and examining C III] and other nebular emission features, I aim to characterize the physical conditions of the z > 6 galaxies that are likely responsible for the cosmic reionization. Finally, with carefully constructed samples and uniform measurements, I investigate the evolution of the ISM/CGM at z ~ 2-4 as probed by rest-UV spectroscopy. I discover redshift-independent correlations among Lya emission, low-ionization interstellar absorption lines, and dust extinction. I further show that the covering fraction of neutral gas decreases with increasing redshift at multiple fixed galaxy properties. Gaining a full understanding of galaxy evolution requires further studies of the ISM/CGM in a systemic manner at higher redshifts. With exceptional capabilities in the near-IR and excellent spectroscopic sensitivity, the next generation of large telescopes will enable rest-UV and rest-optical spectroscopic studies of star-forming galaxies out to z > 10. Answering key questions regarding the interplay among massive stars, their contribution to the ionizing background, and feedback will deliver a clear picture of the formation and evolution of these distant star-forming galaxies.
Download or read book Star Formation Galaxies and the Interstellar Medium written by Jose Franco and published by Cambridge University Press. This book was released on 1993-06-10 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: The enormously powerful phenomena of starbursts are examined in this book. These spectacular star-forming events are seen on large scales in some galaxies, often triggered by galactic interactions. An intriguing implication of starburst research is that active galactic nuclei (AGN) may not be powered by accreting black holes. Instead theories are presented where compact powerhouses of dust-enshrouded star formation lie at the core of AGN, with supernovae exploding roughly once per year within massive nuclear concentrations of gas. This book collects articles from a timely international conference in Elba, Italy, in 1992; these comprise a thorough review of the most important developments in galactic-scale star formation since the starburst revolution of the late 1980s. This text will introduce graduate students to this exciting area and keep experts apace with rapid developments in it.
Download or read book The Interstellar Medium in Galaxies written by J.M. van der Hulst and published by Springer Science & Business Media. This book was released on 2013-12-01 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been more than five decades ago that Henk van de Hulst predicted the observability of the 21-cm line of neutral hydrogen (HI ). Since then use of the 21-cm line has greatly improved our knowledge in many fields and has been used for galactic structure studies, studies of the interstellar medium (ISM) in the Milky Way and other galaxies, studies of the mass distribution of the Milky Way and other galaxies, studies of spiral struc ture, studies of high velocity gas in the Milky Way and other galaxies, for measuring distances using the Tully-Fisher relation etc. Regarding studies of the ISM, there have been a number of instrumen tal developments over the past decade: large CCD's became available on optical telescopes, radio synthesis offered sensitive imaging capabilities, not only in the classical 21-cm HI line but also in the mm-transitions of CO and other molecules, and X-ray imaging capabilities became available to measure the hot component of the ISM. These developments meant that Milky Way was no longer the exclusive playground for ISM studies and that by reaching out to other galaxies astronomy had gained the advantage of having an "outside" view, though at the expense of giving up some linear resolution. Studies of the ISM in other galaxies are intimately connected to studies of the ISM in the Milky Way.
Download or read book The Interstellar Medium in External Galaxies written by David J. Hollenbach and published by . This book was released on 1990 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Demographics of the Cold Universe with ALMA written by Seiji Fujimoto and published by Springer. This book was released on 2022-01-07 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the cold side of the Universe illustrated by the rest-frame, far-infrared emission with Atacama Large Millimeter/submillimeter Array (ALMA). The author constructed the largest-ever ALMA sample and dataset, which enables them to identify very faint, rest-frame, far-infrared dust continuums as well as the carbon fine-structure line emission from distant galaxies that have been missed in previous surveys. The observational findings described in this book reveal for the first time where and how much of the star formation, traced by the rest-frame far-infrared emission, is ongoing, from inter-stellar and circum-galactic media to cosmic structures. Moreover, since some of the findings are unexpected and as such challenge the current galaxy formation models, the book provides exciting questions that should be addressed in the next decades.
Download or read book The Dense Interstellar Medium in Galaxies written by Susanne Pfalzner and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 665 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cologne-Bonn-Zermatt symposium is a well established series of conferences, occurring on a 5-year cycle, on the dense interstellar medium and related topics. The main results constitute valuable proceedings that offer everyone working in this field an authoritative and comprehensive source of reference.
Download or read book The Molecular Interstellar Medium of Nearby Star forming Galaxies written by Andreas Schruba and published by . This book was released on 2011 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interstellar Medium in Lensed Star forming Galaxies at Z 2 5 written by Alasdair Thomson and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Galactic Interstellar Medium written by William Butler Burton and published by Springer. This book was released on 1992 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this volume three extended lectures addressing both students and experienced astronomers and astrophysicists cover a wealth of material on interstellar matter. The first lecture details the most recent observationaldata on interstellar matter inside and outside our galaxy, such as the global distribution of matter and atomic or molecular gas and its kinematics. The second treats its large-scale dynamics, including instabilities and star formation. In the third the physics and chemistry of molecular clouds are discussed. This book can be used as a textbook for advanced students in astrophysics.
Download or read book The Interstellar Medium Expanding Nebulae and Triggered Star Formation written by Thomas G. Bisbas and published by Springer. This book was released on 2015-11-24 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: This brief brings together the theoretical aspects of star formation and ionized regions with the most up-to-date simulations and observations. Beginning with the basic theory of star formation, the physics of expanding HII regions is reviewed in detail and a discussion on how a massive star can give birth to tens or hundreds of other stars follows. The theoretical description of star formation is shown in simplified and state-of-the-art numerical simulations, describing in a more clear way how feedback from massive stars can trigger star and planet formation. This is also combined with spectacular images of nebulae taken by talented amateur astronomers. The latter is very likely to stimulate the reader to observe the structure of nebulae from a different point of view, and better understand the associated star formation therein.
Download or read book The Interstellar Medium written by James Lequeux and published by Springer Science & Business Media. This book was released on 2005-08-29 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describing interstellar matter in our galaxy in all of its various forms, this book also considers the physical and chemical processes that are occurring within this matter. The first seven chapters present the various components making up the interstellar matter and detail the ways that we are able to study them. The following seven chapters are devoted to the physical, chemical and dynamical processes that control the behaviour of interstellar matter. These include the instabilities and cloud collapse processes that lead to the formation of stars. The last chapter summarizes the transformations that can occur between the different phases of the interstellar medium. Emphasizing methods over results, The Interstellar Medium is written for graduate students, for young astronomers, and also for any researchers who have developed an interest in the interstellar medium.
Download or read book The Evolution of the Atomic and Molecular Interstellar Medium in Star forming Galaxies written by Rijksuniversiteit Groningen and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Properties of the Interstellar Medium of the Star forming Galaxy IC10 at Various Spatial Scales written by Fiorella Lucia Polles and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of the Interstellar Medium (ISM) strongly influence the environment and processes that lead to star-formation, which in turn, drives the evolution of a galaxy. Dwarf galaxies in the Local Group are perfect laboratories to investigate how the metal-poor ISM affects the interplay between gas, dust and stars. In this thesis, I investigate the properties of the HII regions and the diffuse ionized gas of the nearby dwarf galaxy IC10, which has a metallicity of 1/3 solar. Its proximity (d=700 kpc) enables the analysis on different spatial scales: from the compact clumps (~25 pc) to the whole star-forming body of the galaxy (~650pc). In order to measure the physical properties of the ISM, I model the infrared emission lines observed with Spitzer and Herschel with photoionization and photodissociation models. I present an extensive exploration of different methods to determine the most reliable ISM properties, based on the available constraints. I determined the properties of the brightest star-forming clumps within the galaxy and show that the emission at large scales (~300 pc) is dominated by that of the compact, bright clumps that lie within the region. I further demonstrate the need for a multi-component model to fully reproduce the observations.
Download or read book The Evolution of Massive Star forming Galaxies written by Alice Lowry Ruth Danielson and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book From Interstellar Clouds to Star forming Galaxies written by International Astronomical Union. Symposium and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The link between the structure of the interstellar medium in galaxies and the star formation process is a fast-growing area of astrophysical research. The availability of wide-field far-infrared and submillimeter surveys with various space observatories, coupled with the improved capabilities of ground-based millimeter and submillimeter interferometers, has led to spectacular advances in our understanding of star formation modes from solar system scales to galaxy scales. IAU Symposium 315 aims to build a coherent picture of how star formation is fueled on a wide range of scales. Bringing together researchers working on star formation throughout the Universe from nearby clouds to local galaxies to the first star-forming galaxies at high redshift, it makes connections between the latest observations and advanced numerical simulations. It also addresses critical issues, such as the origin and universality of the stellar initial mass function, the nature of star formation 'laws', and the role of feedback. -- Publisher description.
Download or read book The Molecular Interstellar Medium in Distant Galaxies written by Melanie Kaasinen and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Identification and Characterization of Local Analogs to High redshift Galaxies written by Skarleth M. Motino Flores and published by . This book was released on 2021 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The universe is constantly changing, astronomers learn about its evolution through carefulobservation of the physical processes happening. For instance, observing our own galaxy we nd star-forming regions, where stars are born after the gravitational collapse of large gas clouds. The life of a star is extended until there is no more gas to burn. Massive stars die with a tremendous supernova explosion, potentially forming black-holes, releasing heavy elements into the interstellar medium in this process. Star formation converts gas into stars, and without gas available is not possible to form stars. The entire life cycle of a star occurs inside a galaxy. Understanding the physical processes driving galaxy formation and evolution is one of the most important goals of observational cosmology. It is also one of the most dicult problems to address due to the large distances and time scales involved. When observing the most distant universe, also known as the high-redshift (high-z) universe, we are observing the young universe, where the rst galaxies were formed. The faintness and small sizes of galaxies in the early universe make detailed observations extremely challenging with current telescopes. An alternative and complementary approach is to identify nearby galaxies that are analogs to distant galaxies, where the physical processes can be studied in greater detail than what is possible in high-z galaxies. I have therefore selected a sample of nearby star-forming galaxies that are potential local analogs to high-z galaxies. These local galaxies are young, star-forming, have low metallicities, and are likely to have star formation histories (SFH) similar to the high-z galaxies. In order to characterize these galaxies, I use observations with the SOFIA telescope together with ancillary data, to study their dust properties and how it is related to the star formation activity. I also use FIR fiine-structure lines to identify the neutral and ionized gas components in the galaxies. My overall aim is to produce a detailed characterization of the properties of the local galaxies and determine their SFH and analyze their connection with photometric and spectroscopic results for high-z galaxies obtained with Herschel and ALMA. In this thesis, I present the dust emission characterization through a two-component black-body, derived using infrared observations with SOFIA/HAWC+ instrument and ancillary data from Spitzer, Herschel, among others. Then I present the spectral energy distribution (SED) from ultraviolet to far-infrared wavelengths for the local analogs to high-z galaxies, which is derived using the fitting procedure Lightning. Also, the ionized gas is characterized by the [CII]-158m and [OIII]-88m fine-structure lines using the SOFIA/FIFI-LS integral eld unit (IFU). These lines are accessible with ALMA for high-z objects and my results for the local analogs can be used to infer the interstellar medium properties of the high-z galaxies.
