Download or read book Development of the 2nd Generation Z Redshift and Early Universe Spectrometer the Study of Far IR Fine Structure Emission in High z Galaxies written by Carl Ferkinhoff and published by . This book was released on 2014 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 2nd generation z (Redshift) and Early Universe Spectrometer (ZEUS-2), is a longslit echelle-grating spectrometer (R~1000) for observations at submillimeter wavelengths from 200 to 850 [mu]m. Its design is optimized for the detection of redshifted far-infrared spectral lines from galaxies in the early universe. Combining exquisite sensitivity, broad wavelength coverage, and large (~2.5%) instantaneous bandwidth, ZEUS-2 is uniquely suited for studying galaxies between z~0.2 and 5-spanning the peaks in both the star formation rate and number of AGN in the universe. ZEUS-2 saw first light at the Caltech Submillimeter Observatory (CSO) in the Spring of 2012 and was commissioned on the Atacama Pathfinder Experiment (APEX) in November 2012. Here we detail the design and performance of ZEUS-2, first however we discuss important science results that are examples of the science enabled by ZEUS-2 Using the first generation z (Redshift) and Early Universe Spectrometer (ZEUS-1) we made the first high-z detections of the [NII] 122 [mu]m and [OIII] 88 [mu]m lines. We detect these lines from starburst galaxies between z ~2.5 and 4 demonstrating the utility of these lines for characterizing the properties of early galaxies. Specifically we are able to determine the most massive star still on the main sequence, the number of those stars and a lower limit on the mass of ionized gas in the source. Next we present ZEUS-2's first science result. Using ZEUS-2 on APEX we have detected the [CII] 158 [MICRO SIGN]m line from the z = 1.78 galaxy H-ATLAS J091043.1-000322 with a line flux of (6.44 ± 0.42) x 10-18 W m-2. Combined with its far-infrared luminosity and a new Herschel-PACS detection of the [OI] 63 [MICRO SIGN]m line we are able to conclude that H-ATLAS J091043.1-000322 is a high redshift analogue of a local ultra-luminous infrared galaxy, i.e. it is likely the site of a compact starburst due to a major merger. This detection, combined with the ZEUS-1 observations of the [NII] and [OIII] lines represent examples of work we plan to continue with ZEUS-2. As such, they demonstrate the potential of ZEUS-2 for increasing our understanding of galaxies and galaxy evolution over cosmic time.
Download or read book How Did the First Stars and Galaxies Form written by Abraham Loeb and published by Princeton University Press. This book was released on 2010-07-19 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: A concise introduction to cosmology and how light first emerged in the universe Though astrophysicists have developed a theoretical framework for understanding how the first stars and galaxies formed, only now are we able to begin testing those theories with actual observations of the very distant, early universe. We are entering a new and exciting era of discovery that will advance the frontiers of knowledge, and this book couldn't be more timely. It covers all the basic concepts in cosmology, drawing on insights from an astronomer who has pioneered much of this research over the past two decades. Abraham Loeb starts from first principles, tracing the theoretical foundations of cosmology and carefully explaining the physics behind them. Topics include the gravitational growth of perturbations in an expanding universe, the abundance and properties of dark matter halos and galaxies, reionization, the observational methods used to detect the earliest galaxies and probe the diffuse gas between them—and much more. Cosmology seeks to solve the fundamental mystery of our cosmic origins. This book offers a succinct and accessible primer at a time when breathtaking technological advances promise a wealth of new observational data on the first stars and galaxies. Provides a concise introduction to cosmology Covers all the basic concepts Gives an overview of the gravitational growth of perturbations in an expanding universe Explains the process of reionization Describes the observational methods used to detect the earliest galaxies
Download or read book Fluctuations in Radiation Backgrounds at High Redshift and the First Stars written by Lauren Nicole Holzbauer and published by . This book was released on 2014 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first stars to light up our universe are as yet unseen, but there have been many attempts to elucidate their properties. The characteristics of these stars (`Population/Pop III' stars) that we do know lie mostly within theory; they formed out of metal-free hydrogen and helium gas contained in dark matter minihalos at redshifts z ~ 20-30. The extent to which Pop III star formation reached into later times is unknown. Current and near future instruments are incapable of resolving individual Pop III stars. Consequently, astronomers must devise creative means with which to indirectly predict and measure and their properties. In this thesis, we will investigate a few of those means. We use a new method to model fluctuations of the Lyman-Werner (LW) and Lyman- & alpha; radiation backgrounds at high redshift. At these early epochs the backgrounds are symptoms of a universe newly lit with its first stars. LW photons (11.5-13.6 eV) are of particular interest because they dissociate molecular hydrogen, the primary coolant in the first minihalos that is necessary for star formation. By using a variation of the `halo model', which describes the spatial distribution and clustering of halos, we can efficiently generate power spectra for these backgrounds. Spatial fluctuations in the LW and (indirectly) the Lyman-[alpha] BG can tell us about the transition from primordial star formation to a more metal-enriched mode that marks the beginning of the second generation of stars in our Universe. The Near Infrared Background (NIRB) has for some time been considered a potential tool with which to indirectly observe the first stars. Ultraviolet (UV) emission from these stars is redshifted into the NIR band, making the NIRB amenable for hunting Pop III stellar signatures. There have been several measurements of the NIRB and subsequent theoretical studies attempting to explain them in recent years. Though controversial, residual levels of the mean NIRB intensity and anisotropies have been detected after subtracting all known foreground stars and galaxies. Pop III stars have been the leading candidates thought responsible for this observed NIRB excess. We model the Pop III stellar contribution to the NIRB mean intensity and fluctuations and generate observationally motivated values of the star formation (SF) efficiency using high redshift measurements of the UV luminosity density with UDF09, UDF12, and WMAP-9 data. This allows us to characterize the properties of a Pop III stellar population that are required to produce the measured excess. Finally, we propose a new method for detecting primordial metal-free and very metal-poor stellar populations by cross-correlating fluctuations in the intensity of Lyman- & alpha; and He II [lambda]1640 emission sourced from high redshifts. Pop III stars are expected to be more massive and more compact than later generations of stars. This results in a much harder ionizing spectrum. A large portion of the ionizing photons have energies with hv> 54.4 eV that carve out substantial patches of doubly ionized helium, He III. These photoionized regions then begin to shine brightly in He II recombination emission. Due to the lack of heavy elements in these regions, Pop III stars must rely on hydrogen and helium for cooling, enhancing both the Lyman-[alpha] and He II emission lines. In this regard, Pop III stars can be characterized as `dual emitters, ' i.e. producers of both Lyman-[alpha] and He II emission signatures. Though Lyman-[alpha] emission is characteristic of both metal-free and metal-enriched stars, He II emission appears to be unique to extremely metal poor stars and metal-free stars, making it a very strong signature of the first stars. Detecting Lyman-[alpha] + He II dual emission in individual galaxies at high redshift is difficult and so far rare. The astrophysical engines powering the few Lyman-[alpha] + He II dual emitters that have been discovered have still not been clearly identified. Alternatively, we may be able to map fluctuations in the total intensity of the Lyman-[alpha] and He II [lambda]1640 lines, which will allow us to indirectly assess sources that are below typical luminosity thresholds of deep surveys. Cross-correlating these lines can provide us with a useful new tool for inferring properties of the first stars, since the two lines together allow us to better isolate the redshift of source emission and the presence of He II [lambda]1640 emission is extremely sensitive to stellar metallicity.
Download or read book From Z machines to ALMA written by Andrew J. Baker and published by . This book was released on 2007 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Universe at High z Large Scale Structure and the Cosmic Microwave Background written by Enrique Martinez-Gonzalez and published by Springer. This book was released on 2014-08-23 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmology has dramatically evolved during the last decade and there has been vast development of, e.g., theories of galaxy formation in connection with the early universe or gravitational lensing. These new developments motivated the editors to organize a school covering all of these ideas and observations in a pedagogical way. The topics covered in the 26 lectures of this summer school include: QSO absorption systems, identification of objects at high redshift, radiogalaxies, galaxy formation and evolution, galaxy number counts, clustering, theories of structure formation, large-scale structure and streaming motions, gravitational lensing, and spectrum and anisotropies of the cosmic microwave background radiation. Observational developments, data analysis, and theoretical aspects are equally treated.
Download or read book The Canada France Deep Fields Photometric Redshift Survey microform an Investigation of Galaxy Evolution Using Photometric Redshifts written by Mark Brodwin and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2004 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress in the study of galaxy evolution has traditionally followed from improvements in spectroscopic measurement techniques and subsequent groundbreaking surveys. The advent of large format CCD detectors, coupled with the demonstrated success of the photometric redshift method, has given rise to a new, potentially very powerful alternative. It has, in fact, motivated the present detailed investigation of the potential of photometric redshift surveys to complement, or in some cases, supersede traditional spectroscopic surveys in galaxy evolution studies. This Thesis describes a new deep, wide-field, multi-colour imaging survey, 10 times deeper and 30 times larger than its spectroscopic predecessor, the Canada-France Redshift Survey (CFRS). Highly accurate photometric redshifts, calibrated using hundreds of spectroscopic CFRS galaxies, were measured for tens of thousands of objects, with typical dispersions of only sigma/(1 + z) & lsim; 0.06 to IAB = 24 for z & le; 1.3. For the 1- and 2-point statistics of the galaxy distribution studied in this Thesis, the measurement accuracy is limited not by the photometric redshift error, but rather by the effect of cosmic variance, whose contribution to the total error budget is dominant. Therefore, future studies will be well served by adopting the photometric redshift approach, the efficiency of which will enable them to survey the hundreds or thousands of square degrees required to obtain a fair sample of the Universe. We measure the evolution of galaxy correlations with redshift, a primary observable of the structure formation process, correcting for the dilutive effect of photometric redshift errors on the clustering signal. The high z & sim; 3 correlation amplitude seen in this work provides compelling evidence for the biased galaxy formation paradigm. The measured galaxy correlations from 0 & lsim; z & lsim; 3 are in excellent agreement with the findings of the largest, state-of-the-art spectroscopic studies. A new Bayesian method to measure the galaxy redshift distribution is developed. The accuracy of the method, which incorporates the full redshift likelihood function of each galaxy in an iterative analysis, is demonstrated in extensive Monte Carlo simulations. IAB and RAB redshift distributions, along with the run of median redshifts, are measured in various magnitude ranges, with special attention given to quantifying both random and systematic errors.
Download or read book Galaxy Formation and Evolution written by Houjun Mo and published by Cambridge University Press. This book was released on 2010-05-20 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: A coherent introduction for researchers in astronomy, particle physics, and cosmology on the formation and evolution of galaxies.
Download or read book The Middle aged Universe written by Alison Laurel Coil and published by . This book was released on 2004 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings Astronomical Society of Australia written by Astronomical Society of Australia and published by . This book was released on 1996 with total page 344 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 University Press. This book was released on 2013-01-15 with total page 572 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 Cosmic Evolution written by Eric J. Chaisson and published by Harvard University Press. This book was released on 2001-02-16 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chaisson addresses some of the most basic issues we can contemplate: the origin of matter and the origin of life, and the ways matter, life, and radiation interact and change with time. He designs for us an expansive yet intricate model depicting the origin and evolution of all material structures.
Download or read book Seeing Red written by Halton C. Arp and published by Apeiron. This book was released on 1998 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Worlds New Horizons in Astronomy and Astrophysics written by National Research Council and published by National Academies Press. This book was released on 2011-02-04 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driven by discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically during the course of the last few decades. The fields of astronomy and astrophysics are making new connections to physics, chemistry, biology, and computer science. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's. Realizing these scientific opportunities is contingent upon maintaining and strengthening the foundations of the research enterprise including technological development, theory, computation and data handling, laboratory experiments, and human resources. New Worlds, New Horizons in Astronomy and Astrophysics proposes enhancing innovative but moderate-cost programs in space and on the ground that will enable the community to respond rapidly and flexibly to new scientific discoveries. The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed. The book is a useful resource for agencies supporting the field of astronomy and astrophysics, the Congressional committees with jurisdiction over those agencies, the scientific community, and the public.
Download or read book The Redshift Controversy written by George B. Field and published by Addison Wesley Longman. This book was released on 1973 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1048 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Spectral Energy Distribution of Galaxies SED 2011 IAU S284 written by Richard J. Tuffs and published by Cambridge University Press. This book was released on 2012-08-30 with total page 533 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent observational developments are providing the first truly panchromatic view of galaxies, extending from the radio to TeV gamma-rays. This is motivating the development of new models for the interpretation of spectral energy distributions (SEDs) of galaxies in terms of the formation, evolution and emission of stellar and accretion-driven sources of photons, the interaction of the photons with the gaseous and dust components of the interstellar medium, and high-energy processes involving cosmic rays. IAU Symposium 284 details progress in the development of such models, their relation to fundamental theory, and their application to the interpretation of the panchromatic emission from the Milky Way and nearby galaxies, connecting the latter with models for the evolution of the SEDs of distant galaxies, and the extragalactic background light. IAU S284 is a useful resource for all researchers working with the copious amounts of multiwavelength data for galaxies now becoming available.
Download or read book Intergalactic Baryon Enrichment and Implications for Galaxy Evolution at High Redshift written by Thomas J. Cooper (Ph. D.) and published by . This book was released on 2018 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we present several surveys of heavy element absorber characteristics at high redshift, gauging properties of diffuse intra- and intergalactic gas in the first several Gyr of the Universe. At z ~ 3.5, we study chemical abundances of Lyman limit systems (LLSs) and evaluate their potential to represent expected reservoirs of cold, low-metallicity gas whose accretion onto galaxies is necessary to maintain star formation. In an initial survey focused only on LLSs identified as potential lowmetallicity absorbers, based on the absence of metal lines in low-resolution spectra, we indeed found the selected systems have low abundances, with a median of [M/H]~ -2.2 and several systems at [M/H]/~ -3, comparable to the intergalactic medium. While this result is tempting to interpret as evidence that a sizable fraction of LLSs are candidates of low-metallicity gas accreting onto galaxies, in a follow-up study of all LLSs at z ~ 3.5 we found that LLS abundances can be reasonably described by a unimodal distribution with [M/H]~ -2.5. Additional diagnostics are hence needed to evaluate if (and how many) low abundance LLSs arise from accretion flows, since the overall LLS abundance distribution overlaps heavily with the IGM at this epoch. In a seperate work that constitutes the largest study of multiple ions in individual metalline absorption systems at z /~ 6, we find that the bulk of high-redshift absorption systems are low-ionization and low-metallicity. Since H i absorption cannot be seen at z >/~ 6, we further argue from incidence rates and absorber characteristics that these absorbers are analogous to strong neutral hydrogen systems seen at lower redshift. We conclude that the non-detection of weaker H i absorption systems (such as LLSs) is consistent with lower metallicities and lower ionization states in the circumgalactic medium than is seen at later times.
