Download or read book Characterizing the X ray Properties and Evolution of Distant Galaxies Using Deep Extragalactic Surveys written by Bret D. Lehmer and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterizing Distant Galaxies written by Seth P. Johnson and published by . This book was released on 2013 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive and robust analysis of galaxies found throughout cosmic time provides the means to probe the underlying characteristics of our Universe. Coupling observations and theory, spectral energy distribution (SED) fitting provides a method to derive the intrinsic properties of distant galaxies which then aid in defining galaxy populations and constraining current galaxy formation and evolution scenarios. One such population are the sub-millimeter galaxies (SMGs) whose high infrared luminosities -- typically associated with dust-obscured star formation -- and redshift distribution places them as likely key components in galaxy evolution. To fully analyze these systems, however, requires a near complete sampling of the full SED, detailed models that encapsulate the variety of physical processes and sophisticated methods for comparing the data and models. In this dissertation, we present the general propose, Monte Carlo Markov Chain (MCMC) based SED fitting routine SED Analysis Through Markov Chains (SATMC) and the insight we have gained in modeling a sample of AzTEC 1.1mm-detected SMGs. The MCMC engine and Bayesian formalism used in the construction of SATMC offers a unique view at the constraints on model parameter space that are often grossly simplified in traditional SED fitting methods. We first present the motivation behind SATMC and its MCMC algorithm. We also highlight a series of test cases that verify not only its reliability but its versatility to various astrophysical applications, including the field of photometric redshift estimation. We then present the AzTEC SMG sample and preliminary results obtained through counterpart identification, X-ray spectral modeling and SED fitting with SATMC. Finally, we present the latest work in detailed SED analysis of SMGs and how these results influence our understanding of the SMG population.
Download or read book Studying Distant Galaxies A Handbook Of Methods And Analyses written by Francois Hammer and published by World Scientific Publishing Company. This book was released on 2016-11-15 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: Distant galaxies encapsulate the various stages of galaxy evolution and formation from over 95% of the development of the universe. As early as twenty-five years ago, little was known about them, however since the first systematic survey was completed in the 1990s, increasing amounts of resources have been devoted to their discovery and research. This book summarises for the first time the numerous techniques used for observing, analysing, and understanding the evolution and formation of these distant galaxies.In this rapidly expanding research field, this text is an every-day companion handbook for graduate students and active researchers. It provides guidelines in sample selection, imaging, integrated spectroscopy and 3D spectroscopy, which help to avoid the numerous pitfalls of observational and analysis techniques in use in extragalactic astronomy. It also paves the way for establishing relations between fundamental properties of distant galaxies. At each step, the reader is assisted with numerous practical examples and ready-to-use methodology to help understand and analyse research.François Hammer worked initially in general relativity and made the first modelling of gravitational lenses prior to their spectroscopic confirmation. Following this, he became co-leader of the first complete survey of distant galaxies, the Canada-France-Redshift Survey. This led to the discovery of the strong decrease of the cosmic star formation density measured from UV light as z=1, which, alongside Hector Flores, they confirmed as bolometric and dust independent. With Mathieu Puech, they then pioneered the 3D spectroscopy of distant galaxies, leading to a major increase of understanding of the dynamic state of distant galaxies evidenced by the scatter of the Tully-Fisher relation. This led them to propose, with the addition to the team of Myriam Rodrigues, that galactic disks may survive or be rebuilt in gas-rich mergers, a scenario that is consistent with contemporary cosmological simulations. Besides extensive observational experience, the authors have led, or are leading, several instruments implemented or to be implemented at the largest telescopes, including VLT/Giraffe, VLT/X-shooter, VLT/MOONS and E-ELT/MOSAIC. They have also developed several observational techniques in adaptive optics, and in sky subtraction for integral field units and fibre instruments.
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 Using Emission Lines to Characterize Galaxy Properties written by Joanna Bridge and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ever since the hydrogen emission line of Lyman-alpha (Ly) has been postulated to hold one of the keys to studying high-redshift galaxies, the question of what emission lines can tell us about the properties and evolution of galaxies has driven much of our research. This work is a survey of emission lines across cosmic history. Just as galaxies evolve with redshift, so does how we can use emission line information from these galaxies. I begin with a study of resolved Ly emission in nearby galaxies, and how we can use pixel-by-pixel photometry to study emission on very small galactic scales and to characterize Ly scattering. Using the Lyman-Alpha Reference Sample, a set of 14 starbursting galaxies with redshifts of 0.02 z
Download or read book Studying Distant Galaxies written by François Hammer and published by World Scientific Publishing Europe Limited. This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Distant galaxies encapsulate the various stages of galaxy evolution and formation from over 95% of the development of the universe. As early as twenty-five years ago, little was known about them, however since the first systematic survey was completed in the 1990s, increasing amounts of resources have been devoted to their discovery and research. This book summarises for the first time the numerous techniques used for observing, analysing, and understanding the evolution and formation of these distant galaxies. In this rapidly expanding research field, this text is an every-day companion handbook for graduate students and active researchers. It provides guidelines in sample selection, imaging, integrated spectroscopy and 3D spectroscopy, which help to avoid the numerous pitfalls of observational and analysis techniques in use in extragalactic astronomy. It also paves the way for establishing relations between fundamental properties of distant galaxies. At each step, the reader is assisted with numerous practical examples and ready-to-use methodology to help understand and analyse research. Fran ois Hammer worked initially in general relativity and made the first modelling of gravitational lenses prior to their spectroscopic confirmation. Following this, he became co-leader of the first complete survey of distant galaxies, the Canada-France-Redshift Survey. This led to the discovery of the strong decrease of the cosmic star formation density measured from UV light as z=1, which, alongside Hector Flores, they confirmed as bolometric and dust independent. With Mathieu Puech, they then pioneered the 3D spectroscopy of distant galaxies, leading to a major increase of understanding of the dynamic state of distant galaxies evidenced by the scatter of the Tully-Fisher relation. This led them to propose, with the addition to the team of Myriam Rodrigues, that galactic disks may survive or be rebuilt in gas-rich mergers, a scenario that is consistent with contemporary cosmological simulations. Besides extensive observational experience, the authors have led, or are leading, several instruments implemented or to be implemented at the largest telescopes, including VLT/Giraffe, VLT/X-shooter, VLT/MOONS and E-ELT/MOSAIC. They have also developed several observational techniques in adaptive optics, and in sky subtraction for integral field units and fibre instruments.
Download or read book The Evolution of Galaxies written by José M. Vilchez and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Hubble Deep Field and the Distant Universe written by Robert Williams and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Hubble Deep Field and the Distant Universe describes a watershed event in the history of astronomy, in addition to recounting the development of space astronomy. Aimed at a wide-ranging audience including amateur astronomers, science historians, researchers, Hubble Space Telescope (HST) aficionados and students interested in science, this book recounts the progression of events that led to the deep field exploration of Robert Williams and the Hubble Deep Field (HDF) team. Giving a fascinating insight into the processes by which astronomical research projects are carried out and unique discoveries are made by HST, this book describes the momentous image that has enabled astronomers to piece together the evolution of the largest structures in the universe."--Source : résumé de l'éditeur.
Download or read book The Luminosity of Distant Galaxies written by Bruno Bertotti and published by . This book was released on 1966 with total page 33 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.
Download or read book Physics Beyond the Standard Models of Particles Cosmology and Astrophysics written by Hans Volker Klapdor-Kleingrothaus and published by World Scientific. This book was released on 2011 with total page 774 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the proceedings of the Fifth International Conference on Physics Beyond the Standard Models of Particle Physics, Cosmology and Astrophysics. It presents a brilliant overview of the status and future potential and trends in experimental
Download or read book Semi parametric Methods to Aid in the Detection and Characterization of Distant Worlds Around Small Stars written by Ryan Edward Cloutier and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Statistical studies of the exoplanet population have provided key insights into their formation histories and evolution. Developing an understanding of the planet formation process requires both accurate and precise measurements of fundamental planetary parameters such as their masses, radii, and orbital characteristics. Planetary systems orbiting low mass stars represent superlative opportunities to characterize exoplanets in detail as they are plentiful within the solar neighbourhood and they are known to commonly host multi-planet systems of terrestrial to Neptune-sized planets that are more easily detectable than similar planets around Sun-like stars. One major deterrent to the characterization of such planets is stellar activity and its manifestation in radial velocity (RV) measurements that can mask and even mimic planetary signals. In this thesis, I develop and implement a formalism aimed at enabling the detection and precise and accurate characterization of planetary systems around low mass stars. This formalism is based around semi-parametric Gaussian process (GP) regression models that are used to simultaneously model planets, in both RV and transit light curve observations, and the temporal covariance structure arising from stellar activity produced by magnetically active regions on the stellar surface. The GP formalism is applied to synthetic RV datasets emulating the upcoming planet detection survey using the near-infrared spectropolarimeter SPIRou and to synthetic optical and near-infrared measurements of the expected population of transiting planets discovered with TESS. I also apply the GP formalism to activity modelling in the K2-18 planetary system from which an accurate and precise planetary mass of its transiting temperate sub-Neptune is inferred along with the presence of an additional planet in the system using RV measurements from HARPS and CARMENES. Lastly, I extend the GP formalism to the treatment of stellar photometric variability and systematic effects in TESS light curves and uncover a number of candidate transiting planets around low mass stars in the first two TESS sectors. Applications of GPs for the detection and characterization of exoplanets will prove to be a crucial tool for developing a global understanding of planet formation and in revealing how common the conditions for life like our own are within our galaxy.
Download or read book Characterizing the Star Forming Properties of Herschel detected Gravitationally Lensed Galaxies written by Gregory Lee Walth and published by . This book was released on 2015 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Star Formation in Distant Galaxies written by Andrew William Blain and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The First Galaxies in the Universe written by Abraham Loeb and published by Princeton Astrophysics. This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies.The First Galaxies in the Universe starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more.Provides a comprehensive introduction to this exciting frontier in astrophysics Begins from first principles Covers advanced topics such as the first stars and 21-cm cosmology Prepares students for research using the next generation of large telescopes Discusses many open questions to be explored in the coming decade "
Download or read book Multi wavelength Analysis of the Physical Properties of Distant Galaxies written by and published by . This book was released on 2011 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Hubble Deep Field written by Space Telescope Science Institute (U.S.). Symposium and published by Cambridge University Press. This book was released on 1998-10-13 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Hubble Deep Field (HDF) is the deepest optical image of the Universe ever obtained. It is the result of a 150-orbit observing programme with the Hubble Space Telescope. It provides a unique resource for researchers studying the formation and evolution of stars and galaxies. This timely volume provides the first comprehensive overview of the HDF and its scientific impact on our understanding in cosmology. It presents articles by a host of world experts who gathered together at an international conference at the Space Telescope Science Institute. The contributions combine observations of the HDF at a variety of wavelengths with the latest theoretical progress in our understanding of the cosmic history of star and galaxy formation. The HDF is set to revolutionize our understanding in cosmology. This book therefore provides an indispensable reference for all graduate students and researchers in observational or theoretical cosmology.
