Download or read book Precision Measurements of Cosmic Microwave Background Polarization to Study Cosmic Inflation and Large Scale Structure written by Darcy Riley Barron and published by . This book was released on 2015 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of cosmic microwave background (CMB) are a powerful tool to study and understand our universe. Detailed characterizations of the temperature of the CMB played a key role in the development of the current standard cosmological model, Lambda CDM. Although this model, along with the standard model of particle physics, describes much of the observed large-scale structure of the universe and its evolution, there are still gaps in our understanding. The next step for answering many of these outstanding questions in cosmology and particle physics lies in the characterization of the CMB B-mode polarization pattern. This faint signal is expected to be imprinted at the formation of the CMB by inflationary gravitational waves in the early universe. Detection of this primordial B-mode signal would not only be the first direct evidence for inflation, but would also constrain inflationary models and determine the energy scale of inflation. Gravitational lensing of CMB E-mode polarization by intervening matter also produces a secondary B-mode polarization signal at smaller angular scales. This signal traces large scale structure in the universe, with information about the distribution and composition of matter. This dissertation describes research in instrumentation, observations, and data analysis for measurements of the CMB B-mode signal, including work on three generations of experiments in this rapidly evolving field. Analysis of the galactic plane and CMB multi-frequency data from the BICEP1 CMB polarization telescope helped further our understanding of polarized CMB foregrounds by studying polarized galactic emission and the structure of the galactic magnetic field. The deployment and first season of observations with the POLARBEAR-1 instrument, a CMB polarization telescope, are described. This instrument reached a milestone in sensitivity with our measurement of a non-zero B-mode polarization power spectrum. Finally, this thesis discusses the design and development of the POLARBEAR-2 instrument, a new receiver with expanded capabilities and sensitivity, scheduled to deploy alongside POLARBEAR-1 in 2016.
Download or read book Measurement of the Polarization of the Cosmic Microwave Background with the BICEP2 and Keck Array Telescopes written by Grant Paul Teply and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precision polarimetry of the cosmic microwave background (CMB) has become a mainstay of observational cosmology. The Lambda-CDM model predicts a polarization of the CMB at the level of a few mu-K, with a characteristic E-mode pattern. On small angular scales, a B-mode pattern arises from the gravitational lensing of E-mode power by the large scale structure of the universe. Inflationary gravitational waves (IGW) may be a source of B-mode power on large angular scales, and their relative contribution to primordial fluctuations is parameterized by a tensor-to-scalar ratio r. BICEP2 and Keck Array are a pair of CMB polarimeters at the South Pole designed and built for optimal sensitivity to the primordial B-mode peak around multipole l ~ 100. The BICEP2/Keck Array program intends to achieve a sensitivity to r [greater than or equal to] 0.02. Auxiliary science goals include the study of gravitational lensing of E-mode into B-mode signal at medium angular scales and a high precision survey of Galactic polarization. These goals require low noise and tight control of systematics. We describe the design and calibration of the instrument. We also describe the analysis of the first three years of science data. BICEP2 observes a significant B-mode signal at 150 GHz in excess of the level predicted by the lensed-Lambda-CDM model, and Keck Array confirms the excess signal at greater than 5-sigma. We combine the maps from the two experiments to produce 150 GHz Q and U maps which have a depth of 57 nK deg (3.4 mu-K arcmin) over an effective area of 400 deg2 for an equivalent survey weight of 248000 mu-K2. We also show preliminary Keck Array 95 GHz maps. A joint analysis with the Planck collaboration reveals that much of BICEP2/Keck Array's observed 150 GHz signal at low l is more likely a Galactic dust foreground than a measurement of r. Marginalizing over dust and r, lensing B-modes are detected at 7.0-sigma significance.
Download or read book The Cosmic Microwave Background written by C.H. Lineweaver and published by Springer. This book was released on 2011-09-20 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Study Institute on the Cosmological Background Radiation, Strasbourg, France, May 27-June 7, 1996
Download or read book The Early Universe and the Cosmic Microwave Background Theory and Observations written by Norma G. Sànchez and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of the Daniel Chalonge School on Astrofundamental Physics is to contribute to a theory of the universe (and particularly of the early universe) up to the marks, and at the scientific height of, the unprecedented accuracy, existent and expected, in the observational data. The impressive development of modern cosmology during the last decades is to a large extent due to its unification with elementary particle physics and quantum field theory. The cross-section between these fields has been increasing setting up Astrofundamental Physics. The early universe is an exceptional (theoretical and experimental) laboratory in this new discipline. This NATO Advanced Study Institute provided an up dated understanding, from a fundamental physics and deep point of view, of the progress and key issues in the early universe and the cosmic microwave background: theory and observations. The genuine interplay with large scale structure formation and dark matter problem were discussed. The central focus was placed on the cosmic microwave background. Emphasis was given to the precise inter-relation between fundamental physics and cosmology in these problems, both at the theoretical and experimental/observational levels, within a deep and well defined programme which provided in addition, a careful interdisciplinarity. Special sessions were devoted to high energy cosmic rays, neutrinos in astrophysics, and high energy astrophysics. Deep understanding, clarification, synthesis, careful interdisciplinarity within a fundamental physics framework, were the main goals of the course.
Download or read book Large scale Measurements of the Cosmic Microwave Background written by Cyndia Blaire Yu and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cosmic microwave background (CMB), the afterglow of the Big Bang, is a cornerstone of modern cosmology. Measuring its features with ever-increasing detail has been key to building and validating our current standard cosmological model, thus motivating further attempts to study the CMB with ever greater precision. First, we present the development of the microwave SQUID multiplexer. We show the design and validation of custom warm readout electronics and discuss studies of the fundamental properties of the device and readout combined system. We discuss the first on-sky CMB demonstration of umux and production-scale development at 910x multiplexing factor for upcoming CMB observatories. Together these efforts increase the achieved multiplexing factor for deployment-grade CMB detector systems by over an order of magnitude. Second, we present measurements of CMB E-mode polarization at large angular scales with the BICEP/Keck program. We show the design and execution of new extended-area observations with BICEP3 to map large-scale E-modes across almost 20\% of the sky. We present the updated analysis pipeline for mapmaking, curved sky power spectrum estimation, and likelihood framework. Preliminary analysis shows sensitivity to new cosmology comparable to the best satellite observation-based constraints, demonstrating the potential of future ground-based surveys. Finally, we live in privileged times in cosmology, with access to unprecedented instruments and computing power. This work cannot be done alone: large collaborations of hundreds of scientists are responsible for producing much of the stunning success of modern cosmology. We present thoughts on structural policies to ensure the diversity, equity, and inclusivity of these large-scale collaborations moving forward.
Download or read book Connecting Quarks with the Cosmos written by National Research Council and published by National Academies Press. This book was released on 2003-03-12 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances made by physicists in understanding matter, space, and time and by astronomers in understanding the universe as a whole have closely intertwined the question being asked about the universe at its two extremesâ€"the very large and the very small. This report identifies 11 key questions that have a good chance to be answered in the next decade. It urges that a new research strategy be created that brings to bear the techniques of both astronomy and sub-atomic physics in a cross-disciplinary way to address these questions. The report presents seven recommendations to facilitate the necessary research and development coordination. These recommendations identify key priorities for future scientific projects critical for realizing these scientific opportunities.
Download or read book Cosmic Microwave Background Polarization Science and Optical Design of the POLARBEAR and Simons Array Experiments written by Frederick Takayuki Matsuda and published by . This book was released on 2017 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cosmic microwave background (CMB) radiation contains great amounts of information that allow for studying the physics of the early universe through constraining cosmological parameters in the standard [Lambda]CDM model. The CMB temperature signal has been measured to high precision, but measuring the CMB polarization signal is still in its early stages. The theoretically small primordial CMB polarization B-mode signal has not yet been measured, but has principle importance in that its existence would be strong evidence of inflation. This measurement allows one to probe the earliest state of the universe at energy scales of 10^16 GeV thought to be near the Grand Unified Theory scale. The B-mode signal arising from weak gravitational lensing by large scale structures provides information about the matter composition of the universe and puts strong constraints on the sum of the neutrino masses. This dissertation discusses the optical design, instrumentation, data analysis, and first season science results of the POLARBEAR experiment, a CMB polarization telescope aimed to measure the B-mode signal. The results show the first evidence of non-zero lensing B-modes at sub-degree angular scales on the sky. The development and measurement results of the Fourier transform spectrometer calibration instrument used to characterize the spectral response of the POLARBEAR detectors are also described. The optical design development and systematic studies for the Simons Array, the next generation installment of the experiment, are described as well. The cross polarization effect of Mizuguchi-Dragone breaking due to a prime focus half-wave plate, and the optical redesign of the Simons Array re-imaging optics for increased optical performance at higher frequencies were studied in detail. The Simons Array is planned to fully deploy in 2018 to further study the CMB with enhanced sensitivity.
Download or read book Precise Measurement of B mode Polarization Signal from the Cosmic Microwave Background with Polarbear and the Simons Array written by Praween Siritanasak and published by . This book was released on 2018 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout history, human beings have always sought to answer the question "what was the origin of the universe?" The Cosmic Microwave Background (CMB) is one of the most essential scientific tools that will help us better understand the universe. The temperature maps of the CMB have allowed us to study the nature of the early universe through the standard [Lambda]CDM model as well as to describe its evolution. Nevertheless, many questions remain. The next step in finding the answer lies in the measurement of the B-mode polarization of the CMB. These faint signals from the primordial universe are expected to be key pieces of evidence of the inflationary gravitational wave. Successful detection of this B-mode polarization would not only serve as direct evidence of the inflation theory but also lead to constraining of inflationary model and the energy scale of inflation. Moreover, the gravitational lensing of CMB E-mode polarization to B-mode polarization signal at small angular scales will allow us to trace back to the distribution of matter in our universe. This dissertation describes the details of the Polarbear instrument which is designed to detect CMB B-mode polarization. The results from the first and second observational season are also described. Furthermore, this dissertation discusses the development of the Simons Array instrument, which is the expansion of Polarbear with expanded capabilities and increased sensitivity. The Simons Array is scheduled to deploy in 2018.
Download or read book Design and Deployment of the POLARBEAR Cosmic Microwave Background Polarization Experiment written by Kam Stahly Arnold and published by . This book was released on 2010 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: POLARBEAR is a Cosmic Microwave Background (CMB) polarization experiment that will measure the CMB polarization angular power spectrum with unprecedented precision, searching for evidence of inflationary gravitational waves and the gravitational lensing of the CMB polarization by large scale structure. This dissertation presents an overview of the design of the instrument, focusing on the design and fabrication of the focal plane, and presents the results of some tests of instrument performance, both in the laboratory and from the initial engineering deployment. The structure of this thesis is as follows: Chapter 1 introduces the theoretical constructs used to describe the CMB polarization anisotropies, and the state of measurements in the field. Chapter 2 gives an overview of the choices made in the instrument design. Chapter 3 discusses the fundamental limits to the sensitivity of bolometric detectors, and chapter 4 explains the design choices involved in populating the focal plane with detectors. Chapter 5 describes the details of the detector architecture and fabrication, and chapter 6 the details of selecting the spectral band of the detectors. Finally, chapter 7 goes through some results obtained before and during the POLARBEAR engineering run in 2010, and comments on the work to be done before the Chilean deployment.
Download or read book Precise Astronomical Polarization Angle Calibration and Its Impact on Studying Lorentz and Parity Violation in the Cosmic Microwave Background written by Martin Frank Navaroli and published by . This book was released on 2020 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precise measurements of the polarization of the Cosmic Microwave Background (CMB) provide a wealth of knowledge regarding fundamental physics and the origins of our universe. We are currently in an era where the CMB polarization B-mode power spectrum is being measured at both small and large angular scales, providing increasingly tighter constraints on both the effects of gravitational lensing and the amount of primordial gravitational waves generated during the epoch of inflation. As we look toward the next generation of ground-based CMB experiments such as the Simons Observatory and CMB-S4, we must further our understanding of the systematic uncertainties that currently limit constraining power on both the tensor-to-scalar ratio and searches for exotic new physics. Lorentz and parity violating physics such as cosmic birefringence have the effect of rotating the polarization of CMB photons as they traverse cosmological distances, generating B-mode polarization signal and non-zero correlations between the CMB temperature and B-mode power spectra as well as the CMB E-mode and B-mode power spectra, both of which are disallowed by the current standard model of cosmology. This cosmic polarization rotation (CPR) is degenerate with an overall detector misalignment of similar angle magnitude. The precision with which current state-of-the-art polarization calibrators are characterized is presently inadequate to allow for meaningful detections of non-zero CPR from physics that diverge from the standard model to be claimed. This dissertation provides an overview of the current CMB polarization calibration standards and methodology in the context of the POLARBEAR-1 and Simons Array experiments, as well as the design and characterization of a novel ground-based absolute polarization calibrator that will enable new searches for Lorentz and parity violating physics. The calibrator's repeatability between calibrations scans was proven to better than 0.1 degrees, and results from calibration performed on the POLARBEAR-1 telescope and the POLARBEAR-2b receiver are presented in this work.
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 Cosmic Microwave Background written by Júlio C. Fabris and published by Springer. This book was released on 2016-10-07 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series of texts composing this book is based on the lectures presented during the II José Plínio Baptista School of Cosmology, held in Pedra Azul (Espírito Santo, Brazil) between 9 and 14 March 2014. This II JBPCosmo has been entirely devoted to the problem of understanding theoretical and observational aspects of Cosmic Background Radiation (CMB).The CMB is one of the most important phenomena in Physics and a fundamental probe of our Universe when it was only 400,000 years old. It is an extraordinary laboratory where we can learn from particle physics to cosmology; its discovery in 1965 has been a landmark event in the history of physics.The observations of the anisotropy of the cosmic microwave background radiation through the satellites COBE, WMAP and Planck provided a huge amount of data which are being analyzed in order to discover important informations regarding the composition of our universe and the process of structure formation.
Download or read book Measuring the Polarization of the Cosmic Microwave Background with the Keck Array and Bicep2 written by Sarah Kernasovskiy and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Inflation, the theory that the early universe underwent a brief period of exponential expansion, extends the standard model of cosmology to resolve the isotropy, flatness, entropy, and monopole problems. Quantum fluctuations in the inflationary field set the initial seeds of matter which became the temperature anisotropies in the cosmic microwave background (CMB) and later formed the large scale structures of the universe. Quantum fluctuations of the gravitational field during inflation are predicted to produce a stochastic background of gravitational waves which would leave an imprint in the B-mode (curl) component of the polarization of the CMB, with an amplitude dependent on the energy scale of inflation. Bicep2 and the Keck Array are telescopes designed specifically to measure the B-mode polarization at degree-angular scales. They are a set of cryogenically cooled telescopes with refracting, on-axis optics with an aperture of 26.4 cm. The Keck Array has a combined imaging array of 2500 antenna-coupled TES bolometers read with a SQUID-based time-domain multiplexing system. All five of the Keck Array telescopes observed a 400 square degree patch from the South Pole at 150 GHz in 2012-2013, with an achieved sensitivity of 9 micro-K/rt(s) for the 2013 season. This thesis will focus on the optimization and characterization of the Keck Array, as well as the combined cosmology results from the Keck Array with Bicep2. The Keck Array data are consistent with the Bicep2 detection of B-mode polarization at degree-angular scales and increases the sensitivity of the measurement by a factor of 2.
Download or read book CMB Polarization Workshop written by Scott Dodelson and published by American Institute of Physics. This book was released on 2009-06-24 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: The workshop brought together experts in astronomy and particle physics to make the science case for a satellite mission to measure the polarization of the cosmic microwave background (CMB). Detailed maps of the CMB polarization will potentially reveal clues about the origin of the universe. An early epoch of inflation typically produces a spectrum of gravitational waves and these leave a distinctive imprint on the CMB polarization field. The workshop addressed all theoretical aspects of this science: which inflationary models predict an amplitude that will be detected and which do not? What do alternatives to inflation predict? Apart from the gravitational wave signal, what other science can be gleaned from these measurements? High resolution maps should have traces of gravitational lensing which in turn is affected by dark energy and massive neutrinos. How well will a satellite mission be able to measure these effects? CMB polarization also speaks to the end of the Dark Ages; the constraints on reionzation are discussed in the context of all other probes. Finally, several articles – based on many talks and follow-up work – probe the science of and removal of Galactic foregrounds.
Download or read book Exploring the Universe with the Atacama Cosmology Telescope written by Marius Lungu and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past twenty-five years, observations of the Cosmic Microwave Background (CMB) temperature fluctuations have served as an important tool for answering some of the most fundamental questions of modern cosmology: how did the universe begin, what is it made of, and how did it evolve? More recently, measurements of the faint polarization signatures of the CMB have offered a complementary means of probing these questions, helping to shed light on the mysteries of cosmic inflation, relic neutrinos, and the nature of dark energy. A second-generation receiver for the Atacama Cosmology Telescope (ACT), the Atacama Cosmology Telescope Polarimeter (ACTPol), was designed and built to take advantage of both these cosmic signals by measuring the CMB to high precision in both temperature and polarization. The receiver features three independent sets of cryogenically cooled optics coupled to transition-edge sensor (TES) based polarimeter arrays via monolithic silicon feedhorn stacks. The three detector arrays, two operating at 149 GHz and one operating at both 97 and 149 GHz, contain over 1000 detectors each and are continuously cooled to a temperature near 100 mK by a custom-designed dilution refrigerator insert. Using ACT's six meter diameter primary mirror and diffraction limited optics, ACTPol is able to make high-fidelity measurements of the CMB at small angular scales (l ~ 9000), providing an excellent complement to Planck. The design and operation of the instrument are discussed in detail, and results from the first two years of observations are presented. The data are broadly consistent with /\CDM and help improve constraints on model extensions when combined with temperature measurements from Planck.
Download or read book Measurement of the Cosmic Microwave Background Polarization with the BICEP Telescope at the South Pole written by Yuki David Takahashi and published by . This book was released on 2010 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: The question of how exactly the universe began is the motivation for this work. Based on the discoveries of the cosmic expansion and of the cosmic microwave background (CMB) radiation, humans have learned of the Big Bang origin of the universe. However, what exactly happened in the first moments of the Big Bang? A scenario of initial exponential expansion called "inflation" was proposed in the 1980s, explaining several important mysteries about the universe. Inflation would have generated gravitational waves that would have left a unique imprint in the polarization of the CMB. To search for this evidence for inflation, a team gathered in 2002 to design a telescope experiment called BICEP. Sited at the South Pole, BICEP was a novel 25-cm aperture refractor with 49 pairs of polarization-sensitive bolometers. We completed 3 years of successful observations from February 2006 to December 2008. To constrain the amplitude of polarization resulting from inflation, expected to be at least 7 orders of magnitude fainter than the 3 K CMB intensity, precise control of systematic effects is essential. A crucial challenge is preventing systematic errors from introducing false polarization anisotropy signal at the level corresponding to ̃0.1 [mu]K in amplitude. One main focus of this thesis is the characterization of systematic effects for BICEP. We developed a simulation framework for propagating instrumental systematic effects to the final polarization results. Based on these simulations, we established benchmarks for the characterization of critical instrumental properties including bolometer relative gains, beam mismatch, polarization orientation, telescope pointing, sidelobes, thermal stability, and timestream noise model. Guided by these benchmarks, we carefully measured these properties and have shown that we have characterized the instrument adequately to ensure that systematic errors do not limit BICEP's current cosmology results. We have analyzed the first 2 years of data, lowering the upper limits on the gravitational-wave induced polarization by an order of magnitude over all previous experiments. The systematic error analysis has identified what future refinements are likely necessary to probe CMB polarization down to levels corresponding to inflationary energy scales below 2 × 1016 GeV.
Download or read book Cosmic Inflation written by Steff Jaywan and published by Dedona Publishing. This book was released on with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: The concept of cosmic inflation stands as one of the most revolutionary and compelling ideas in modern astrophysics. First proposed in the early 1980s, inflation theory has transformed our understanding of the universe's earliest moments, providing profound insights into its large-scale structure and the intricate patterns of galaxies we observe today. This book goes on a journey to unravel the complexities of this remarkable theory, exploring its origins, implications, and the compelling evidence that supports it. Cosmic inflation posits that the universe underwent an exponential expansion within a fraction of a second after the Big Bang. This rapid inflation smoothed out any initial irregularities, setting the stage for the universe's current uniformity and flatness. It also stretched quantum fluctuations to astronomical scales, seeding the formation of galaxies and cosmic structures. Through this lens, we gain a clearer picture of how the universe evolved from a hot, dense state to the vast, structured cosmos we inhabit. This book is designed to cater to both curious laypersons and dedicated students of cosmology. We will delve into the fundamental principles of inflation theory, explore its mathematical underpinnings, and examine the observational evidence that lends it credence. From the cosmic microwave background radiation to the distribution of galaxies, we will see how inflation theory elegantly explains many of the universe's most perplexing features. This book is designed to cater to both curious laypersons and dedicated students of cosmology. We will delve into the fundamental principles of inflation theory, explore its mathematical underpinnings, and examine the observational evidence that lends it credence. From the cosmic microwave background radiation to the distribution of galaxies, we will see how inflation theory elegantly explains many of the universe's most perplexing features.
