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 Lyman Alpha Emitting Galaxies at High Redshift written by Steven Arthur Dawson and published by Universal-Publishers. This book was released on 2005 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: As late as 1995, the anticipated widespread population of primeval galaxies remained at large, lurking undetected at unknown redshifts, with undiscovered properties. We present results from our efforts to detect and characterize primeval galaxies by their signature high-redshift Lyman-alpha emission lines utilizing two observational techniques: serendipitous slit spectroscopy and narrowband imaging. By pushing these techniques to their utmost limits, we probe the Lyman-alpha-emitting galaxy population out to redshifts as high as z = 6.5. Galaxies at this epoch reside in a universe which is just 800 million years old, a mere 6% of its current age. As such, this work provides one account of the manner by which observational cosmology has recently shifted from merely marveling at the incredible lookback times implied by the first few high-redshift detections, to the routine assembly of high-redshift datasets designed to address specific astrophysical issues.

Download or read book Understanding Large Scale Structure Galaxies and Ionized Gas at Z 2 3 written by Michael Weber Topping and published by . This book was released on 2020 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the nature and evolution of the high-redshift universe is crucial in forming complete models of galaxy evolution and large-scale structure formation. In this dissertation I investigate several aspects of the high-redshift universe, including the structure of a massive galaxy protocluster, understanding the nature and interplay between massive stars and ionized gas in high-redshift galaxies. First, I present an analysis of densely sampled spectroscopic observations of galaxies within the SSA22 protocluster at z~3.09 which reveal two distinct structures separated in redshift space and segregated on the sky. An analysis of similar structures within cosmological N-body simulations reveals that such a distribution of galaxies can only be explained as two nearby overdensities which will remain distinct as they evolve to z=0. Based on the N-body simulations, I find that the opportunity to observe such a phenomenon is incredibly rare, with an occurrence rate of 7.4 h^3 Gpc^ 3. In this dissertation I also investigate the differences between local and high-redshift galaxies suggested by the offset towards higher [OIII]5007/Hb and [NII]6584/Ha on the `BPT' diagram. I analyze combined rest-UV and rest-optical spectra of high-redshift galaxies. Crucially, rest-UV spectra provide a powerful constraint on the population of massive stars within high-redshift galaxies, which is an important driver powering the observed rest-optical emission lines. To investigate this origin of the offset on the BPT diagram, I construct two composite spectra composed of high-redshift galaxies at different locations on the BPT diagram. This analysis demonstrates that high-redshift galaxies that are more offset typically have younger stellar ages, lower stellar metallicities, higher ionization parameters, and are more alpha-enhanced compared to high-redshift galaxies that lie along the local sequence. In addition, this analysis reveals that even galaxies that are entirely consistent with the local nebular excitation sequence appear to be alpha-enhanced. This suggests that a similarity in the location of high-redshift and local galaxies in the BPT diagram may not be indicative of a similarity in their physical properties. I further expand upon this analysis by fitting the joint rest-UV and rest-optical properties of individual galaxies in the sample. An important aspect of analyzing individual galaxy spectra is a quantitative limit on how well we can fit the spectra. By introducing noise to model galaxy spectra which has known properties, and binding its best-fit properties, I determine that galaxy properties can be accurately reproduced if the spectrum has a SNR>4. The best-fit properties of individual galaxies in our sample reveals that they have comparable ionization parameters to those of local HII regions the share the same nebular metallicity. In addition, I find that all galaxies in the sample show evidence for being alpha-enhanced resulting in harder ionizing spectra compared to local galaxies. These results point toward the observed offset on the BPT diagram being primarily caused by a harder ionizing spectra at fixed nebular metallicity.

Download or read book High Redshift Galaxies written by Immo Appenzeller and published by Springer Science & Business Media. This book was released on 2009-06-17 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: The high-redshift galaxies became a distinct research ?eld during the ?nal decade of the20thcentury. AtthattimetheLyman-breaktechniquemadeitpossibletoidentify signi?cant samples of such objects, and the new generation of 8 to 10-m telescopes resulted in ?rst good spectroscopic data. Today the high-redshift galaxies have developed into one of the important topics of astrophysics, accounting for about 5–10% of the publications in the major scienti?c journals devoted to astronomy. Because high-redshift galaxies is a rapidly developing ?eld and since new results are published constantly, writing a book on this topic is challenging. On the other hand, in view of the large amount of individual results now in the literature, and in view of the still growing interest in this topic, it appears worthwhile to summarize and evaluate the available data and to provide an introduction for those who wish to enter this ?eld, or who, for various reasons, might be interested in its results. The end of the ?rst decade of the 21st century appears to be a good point in time to attempt such a summary. The current generation of ground-based 8 to 10-m - optical telescopes, the Hubble Space Telescope, and the most important large radio telescopes have by now been in operation since about one or two decades. Although these instruments will continue to produce important scienti?c results for some time to come, many of the initial programs exploiting their unique new possibilities have been completed.

Download or read book Detection and Analysis of High Redshift Clusters of Galaxies from the Palomar Distant Cluster Survey written by Lori M. Lubin and published by . This book was released on 1995 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Galaxies at High Redshift written by I. Pérez-Fournon and published by Cambridge University Press. This book was released on 2003-03-20 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents lectures of the XI Canary Islands Winter School of Astrophysics written by experts in the field.

Download or read book A Morphological Analysis of High Redshift Galaxy Mergers Using Machine Learning written by Caitlin Rose and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Galaxy mergers play an important role in the formation and evolution of galaxies. However, identifying mergers can be difficult, especially at high redshift, due to effects such as: cosmological surface brightness dimming, poor resolution of images, the shifting of optical light to the infrared, and the inherently more irregular morphologies of younger galaxies. The advent of JWST and new deep, high-resolution near-infrared NIRCam images from the Cosmic Evolution Early Release Science Survey (CEERS) will help mitigate some of these problems to better detect high redshift merger features. Simultaneously, sophisticated machine learning analysis techniques have the potential to more accurately identify mergers by exploiting complex multidimensional data (whether directly from multi-band images or from pre-computed quantitative measurements). In this dissertation, we investigate the use of machine learning techniques (random forests and convolutional neural networks) to identify high redshift galaxy mergers. We create simulated JWST CEERS NIRCam images in six filters and HST CANDELS/Wide WFC3/ACS images in four filters from IllustrisTNG and the Santa Cruz SAM. We use these simulated data to train the algorithms. We calculate morphology parameters for galaxies in those images using Galapagos-2 and statmorph, which are used as inputs for the random forests. We also cut stamps of uniform size for those galaxies, which are used as inputs to the convolutional neural networks. The input labels for the simulated galaxies were derived from Illustris merger history catalogs, such that “mergers” are galaxies that have experienced or will experience a merger within ±250 Myr and “non-mergers” are those that will not experience a merger within that time frame. We train random forests on simulated CEERS galaxies from 0.5

Download or read book Quantifying the Physical Properties of High redshift Galaxies written by Sara Michelle Petty and published by . This book was released on 2010 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: I demonstrate that multi-wavelength analysis is fundamental to the understanding of galaxy evolution. I determined that G-M20 values of Balmer-break galaxies are more bulge-like in the rest-frame optical than z & sim; 1 and 4 starburst galaxies in the UV. I conclude that the Balmer-break selected galaxies are probably progenitors to local early type galaxies.

Download or read book The Influence of Environment on High redshift Cluster Galaxies written by Anna Delahaye and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Galaxy properties such as colour, star-formation rate, and morphology are influenced by the environments in which they reside. In particular, the environments of galaxy clusters have been shown be very efficient at quenching star-formation and altering other observed galactic properties, although the specific mechanisms responsible for this evolution are not fully understood. Additionally, the effect that the cluster environment has on galaxies does not appear to be consistent at all redshifts, with high-redshift cluster galaxies having different observed properties compared to their local counterparts. In this thesis, two studies are presented that investigate the role of high-redshift galaxy cluster environments on their galactic populations.The first study is an extensive photometric survey of the supercluster RCS2319+00, a massive supercluster system comprising three virialized cluster cores in close proximity with one another in projected space as well as redshift space. The system is located at a redshift of z = 0.9 and is expected to merge into a single 10^15 solar mass cluster by z = 0.5, and is therefore a progenitor of the most massive cluster systems we see in the nearby universe today. Spectroscopic and submillimetre surveys have previously uncovered a complicated system of filamentary structure and infalling groups. To complement the previous studies, we assemble a large multiwavelength catalogue to identify cluster members based on photometric properties.With a photometric catalogue complete with photometric redshifts for over 16,000 objects across the central RCS2319 field, we compile a cluster catalogue of nearly 1,800 cluster members. Using proxies for both local and global environments, we investigate the mass and colour properties of cluster galaxies depending on their specific environments within the supercluster. While we do not find a strong dependence on global environment, we do recover both a mass-density and colour-density relation depending on the local overdensity suggesting that immediate surroundings influence galactic properties more strongly than the overall structure in which it resides.The second study presented investigates the presence of merging systems in high-redshift cluster environments compared to the field. We use a sample of four galaxy clusters (1.59

Download or read book Chemodynamical Properties of Simulated Late type Galaxies written by Kate Pilkington 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 Neutral Gas Properties of High redshift Analog Galaxies written by Alexandra Le Reste and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photometric Redshifts and High Redshift Galaxies written by Ray J. Weymann and published by . This book was released on 1999 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 52 papers respond to the explosion of the search for and discovery of high redshift galaxies and the application of broad-band photometry to obtain remarkably reliable estimates of the redshifts of galaxies at all redshifts, spurred not only by the Hubble Deep Fields, but also by the advent of wide-field CCDs on ground-based telescopes and the development of sensitive infrared, submillimeter, and millimeter instrumentation. They discuss techniques, findings, and integrating new data into existing models of galaxy formation and evolution.

Download or read book Literature 1986 Part 1 written by Prof. Dr. Roland Wielen and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Second Annual Spitzer Science Center Conference written by Ranga-Ram Chary and published by . This book was released on 2008 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In November 2005, the 2nd annual Spitzer Science Center international conference was held in Pasadena, California, USA. The purpose of this conference was to provide an overview of the role that infrared imaging and spectroscopy play in revealing the nature of astrophysical environments. Particular emphasis was given to how mid-infrared spectroscopy can disentangle the contribution of star-formation and active galactic nuclei to the bolometric luminosity of individual extragalactic sources. The conference was motivated by the wealth of data from the first two years of operation of the Spitzer Space Telescope but included contributions from ground-based imaging and spectroscopy as well. A wide variety of astrophysical objects were covered, ranging from star-forming regions in local galaxies, including our own, to high redshift galaxies at the epoch of reionization. The conference included 14 review talks, 45 contributed talks, 112 posters, and a brainstorming discussion on what Spitzer should do next. The conference and these proceedings clearly highlight the fundamental role that the infrared plays in providing a more complete picture of galaxy formation and evolution over cosmic time." -- publisher's website.

Download or read book Astrophysics Of Gas Nebulae and Active Galactic Nuclei written by Donald E. Osterbrock and published by University Science Books. This book was released on 2006 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thoroughly revised and expanded throughout, the new edition is a graduate-level text and reference book on gaseous nebulae, nova and supernova remnants. Much of the new data and new images are from the Hubble Space Telescope with two wholly new chapters being added along with other new features. The previous edition which was tried and tested for thirty years has now been succeeded by a revised, updated, larger edition, which will be valuable to anyone seriously interested in astrophysics.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Data Mining and Knowledge Discovery written by and published by . This book was released on 2003 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: