Download or read book Optimization of Future Projects for the Measurement of Cosmic Microwave Background Polarization written by Thuong Duc Hoang and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probing Cosmology with Quad written by Melanie Bowden and published by . This book was released on 2004 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Illuminating the Background written by Nathan James Miller and published by . This book was released on 2012 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cosmic microwave background provides a wealth of information about the origin and history of the universe. The statistics of the anisotropy and the polarization of the cosmic microwave background, among other things, can tell us about the distribution of matter, the redshift of reionization, and the nature of the primordial fluctuations. From the lensing of cosmic microwave background due to intervening matter, we can extract information about neutrinos and the equation of state of dark energy. A measurement of the large angular scale B-mode polarization has been called the "smoking gun'' of inflation, a theory that describes a possible early rapid expansion of the universe. The focus of current experiments is to measure this B-mode polarization, while several experiments, such as POLARBEAR, are also looking to measure the lensing of the cosmic microwave background. This dissertation will discuss several different topics in cosmic microwave background polarization research. I will make predictions for future experiments and I will also show analysis for two current experiments, POLARBEAR and BICEP. I will show how beam systematics affect the measurement of cosmological parameters and how well we must limit these systematics in order to get unbiased constraints on cosmological parameters for future experiments. I will discuss a novel way of using the temperature-polarization cross-correlation to constrain the amount of inflationary gravitational waves. Through Markov Chain Monte Carlo methods, I will determine how well future experiments will be able to constrain the neutrino masses and their degeneracy parameters. I will show results from current data analysis and calibration being done on the Cedar Flat deployment for the POLARBEAR experiment which is currently being constructed in the Atacama desert in Chile. Finally, I will analyze the claim of detection of cosmological birefringence in the BICEP data and show that there is reason to believe it is due to systematic effects in the data.
Download or read book Measuring the Polarization of the Cosmic Microwave Background with POLARBEAR 1 and Developing the Next Generation Experiment POLARBEAR 2 written by Tucker Elleflot and published by . This book was released on 2019 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the polarization of the Cosmic Microwave Background (CMB) have the potential to provide very strong evidence for cosmic inflation. However, the polarization signal that is expected to have been created by inflation is extremely small. This has motivated the construction of extremely sensitive instruments with thousands of cryogenic detectors. Simons Array is a CMB polarization experiment comprised of three telescopes located in northern Chile and each containing a cryogenic receiver. The Simons Array will observe in four frequency bands in order to measure the CMB signal as well as polarized foreground signals. The design of the detectors and readout system has been optimized to provide a low noise measurement and an experiment that can observe in varying weather conditions. Characterizing the detectors and readout system has been a crucial part of the development of the Simons Array receivers. This dissertation describes the development and deployment of the Simons Array experiment with a focus on characterization of the cryogenic detector and readout electronics.
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 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 A Measurement of the Cosmic Microwave Background Polarization with the South Pole Telescope written by and published by . This book was released on 2013 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present maps of the cosmic microwave background (CMB) polarization at 90 and 150 GHz measured with SPTpol and the first EE and TE CMB power spectrum measurements from SPTpol. We also describe the SPTpol instrument in detail. We discuss the development of the SPTpol camera including the cryogenic design and the transition edge sensor (TES) detectors developed at NIST and Argonne National Laboratory. The goals of the SPTpol project are to exploit the high resolution of the telescope (1 arcminute beam) and the high sensitivity afforded by the 1536 detector camera to measure the E-mode power spectrum of the CMB, characterize the B-mode polarization induced by the gravitational lensing of the primordial E-mode CMB polarization, and to detector set an upper limit on the level of the B-mode polarization from inflationary gravitational waves. This thesis is a first step toward accomplishing these goals. Measuring the E-mode power spectrum will allow us to improve constraints on parameters of the current cosmological models that are sensitive to the damping tail of the CMB.
Download or read book Measurement of the Polarization of the Cosmic Microwave Background written by Byron Jacob Philhour and published by . This book was released on 2002 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optimizing Future CMB Observatories and Measuring Galaxy Cluster Motions with the Atacama Cosmology Telescope written by Patricio Andres Gallardo Matamala and published by . This book was released on 2019 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmic Microwave Background (CMB) experiments are a great tool to probe the universe's history and content. In the recent decade, great progress in large format detector array technologies has allowed increased sensitivity and sky coverage, which has enabled very precise measurements. The next generation of CMB experiments will offer larger focal planes, which will allow measurements with exquisite precision. In this thesis, the following studies are presented: The development of a silicon meta-material deep reactive ion etched anti-reflection coating for use in sub-millimeter wavelengths. Characterization of the aliased detector noise performance of the Atacama Cosmology Telescope (ACT), a current polarization sensitive six-meter telescope that observes the CMB at arcminute resolution. Optical models developed to describe the pickup and sidelobes characteristics of the ACT. These models are currently being used to optimize the design of the Simons Observatory, a next generation six-meter telescope with increased sensitivity. Studies of the motions of clusters of galaxies via the pairwise kinetic Sunyaev-Zeldovich effect (the frequency-distortion of the cold CMB light due to the interaction with the hot inter-cluster ionized gas), with data from ACT.
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 Use of Superconducting Bearings to Measure the Polarization of the Cosmic Microwave Background Radiation written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We report on measurements of the coefficient of friction as a function of temperature between 15 and 80 K, of rotation frequency between 0.3 and 3.5 Hz, of levitation distance between 6 and 10 mm, and of ambient pressure between 1 and 10−7 torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.
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 A Measurement of the Temperature and Polarization Anisotropies of the Cosmic Microwave Background Radiation written by William Claude Jones and published by . This book was released on 2005 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of the Cosmic Microwave Background Radiation Polarization Anisotropy at 40Ghz and 90Ghz with the Q U Imaging ExperimenT QUIET written by Alison Rebecca Brizius and published by . This book was released on 2011 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: The polarization of the Cosmic Microwave Background (CMB) contains a wealth of untapped information that will enable us to probe the structure and dynamics of the early universe. The Q/U Imaging ExperimenT (QUIET) was designed to measure these CMB polarization anisotropies at angular scales of 25
Download or read book Measurements of the Cosmic Microwave Background and Foregrounds with the Planck and BOORERanG Experiments written by Marcella Veneziani and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cosmic Micro wave Background (CMB) is one of the main observables in cosmology. Many experiments are aimed at studying its temperature and polarization fluctuations. Several components. called foregrounds, pollute the CMB signal. Using measurements at multiple frequencies, the foregrounds can be studied and removed from the CMB. In the first part of my thesis I collaborated in the characterization and calibration of the focal plane of the High Frequency Instrument of PLANCK in order to measure the orientation and polarization efficiency of the detectors. Understanding these quantities is very important for the analysis of future PLANCK data, especially for the polarization analysis. In the second part of my thesis I worked on BOOMERanG 2003 (B03) data focusing on the science of foregrounds. At B03 frequencies, the brightest signal besides the CMB is the emission of thermal dust from our own Galaxy. Combining B03 data with other experiments I measured the temperature and spectral index of emissivity of several dust structures. I found two different temperature components, and an inverse correlation between dust temperature and spectral index. The B03 frequencies range is also well suited to study the Sunyaev-Zel'dovich (SZ) effect. The SZ is the inverse Compton scattering of CMB photons by hot electrons in galaxy clusters. I separated the SZ component from the others present in this region and frequency range, produced a multi-frequency power spectrum, and used it to constrain the our understanding of matter fluctuations in the Universe.
Download or read book Measuring the Cosmic Microwave Background Radiation from Chile written by Jason Roland Stevens and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precise measurement of the cosmic microwave background (CMB) radiation holds the key to a surprising quantity of knowledge about cosmology and the early universe. Measurement of the power spectrum of the CMB yields information about inflation and gravitational waves in the early universe, the mass of the neutrino, and the number of effective neutrino species. As CMB photons pass through our universe, the interaction they have with its contents yield even more information. Scattering of the CMB photons off of the electrons in galaxy clusters can be used to extract the movement of those galaxy clusters, and gravitational lensing of the CMB photons tells the story of the evolution of massive structures in our universe. Extracting this information requires an extreme level of precision and care in the detection of these photons. This dissertation covers a number of subjects related to measuring CMB photons with telescopes in Chile. I first discuss the superconducting transition edge sensors used on some of these telescopes, and the testing and characterization of these sensors for the Simons Observatory. It is necessary to multiplex the detector signals to reduce thermal load on the cryostat cold stages, so I then discuss testing and characterization strategies for superconducting multiplexers. This begins with characterization of the time domain multiplexing chips used on Advanced ACTPol, and leads into characterization of microwave multiplexing chips like those that will be used in the Simons Observatory. Next, I present methods for designing and optimizing wide area CMB survey strategies from Chile, including the strategies that are used in Advanced ACTPol and the strategies that will be used in the Simons Observatory. I then describe recent results from the Atacama Cosmology Telescope that this work has contributed to. I conclude by summarizing the improvements we will see in measurements of the CMB from new observatories in the coming years.
