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 Measuring Polarization of the Cosmic Microwave Background with the South Pole Telescope Polarization Experiment written by James Sayre and published by . This book was released on 2014 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: The South Pole Telescope Polarization experiment (SPTpol) is a camera consisting of 180 (588) pixels observing bands centered at 90 (150) GHz, installed on the South Pole Telescope in December 2012. It is a high-resolution, high-sensitivity instrument for mapping the polarized component of the Cosmic Microwave Background. In this thesis, we describe the development, testing, and deployment of transition edge sensor (TES) bolometers that make up the camera pixels, as well as the data analysis pipeline used to generate power spectra of the CMB. The tests used to measure various detector properties are described and their results displayed, and details of the analysis routines are explained. We conclude with preliminary results from SPTpol and a discussion of future directions for the experiment.
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 A Polarization Sensitive Bolometer Array for the South Pole Telescope and Measurements of Cosmic Microwave Background Secondary Anisotropies written by Elizabeth Marie George and published by . This book was released on 2013 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past several decades, measurements of the Cosmic Microwave Background (CMB) have been a major driving force in our understanding of cosmology. Measurements of the CMB on large angular scales places tight constraints on the parameters of the Lambda-CDM cosmological model. Measurements of the CMB at smaller angular scales constrains secondary anisotropies, such as the thermal and kinetic Sunyaev Zel'dovitch (tSZ and kSZ) effects, which constrain the structure of the universe at later times. The CMB is also polarized, and the polarization signal encodes information about both the inflationary era and late-time structure formation in our universe. In the first part of this dissertation, I introduce the CMB and discuss the measurements that have been made so far and what we can learn from them. The South Pole Telescope (SPT) is a 10 meter telescope that is dedicated to measuring the CMB down to small angular scales. So far, the SPT has housed two instruments, SPT-sz and SPT-pol. SPT-sz was sensitive to temperature and completed a 2540 square degree survey of the southern sky from 2008-2011. SPT-pol is a polarization sensitive camera that was deployed in 2012, and has been conducting a polarization survey since that time. These instruments both use photon-noise limited superconducting Transition Edge Sensors (TESes) in large numbers to obtain their high sensitivities. TES design and fabrication in large format arrays was critical to the success of these instruments. The second part of this dissertation focuses on the instrumentation of the SPT. I present the theory behind TES bolometer design with a focus on detector stability and optimal performance. Finally, I discuss the design and performance of the two instruments, with a focus on the detector development for the SPT-pol instrument. In the final part of this dissertation, I use the full 2540 square degree SPT-sz survey to measure the power spectrum from 1850
Download or read book Measurement of the Polarization of the Cosmic Microwave Background with BICEP3 and the Keck Array Telescopes written by Jae Hwan Kang and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cosmic Microwave Background (CMB) shows the afterglow image of the Big Bang, providing a window to probe the very early Universe. The CMB encodes the information in the temperature and polarization fluctuations. BICEP3 and the Keck Array telescopes are small aperture refracting telescopes at the South Pole to measure the B-mode polarization of the CMB at the degree angular scales, which holds a key to probe inflation theory. This dissertation presents the progress of the BICEP/Keck Array telescopes on measuring the B modes and the recent test of low elevation observation with BICEP3 to expand its sky coverage at the South Pole. The BICEP/Keck Array telescopes produced the tightest constraint to the power of primordial B-modes, parameterized by the tensor-to-scalar ratio, r, to be less than 0.07 at 95% confidence with the one sigma uncertainty in r about 0.02, using polarization data up to 2015 observing season. BICEP3 was fully deployed for 2016 observing season and has been operating since. Together with the Keck Array telescopes operating at higher frequencies, we expect to achieve the one sigma uncertainty in r about 0.01 from data up to 2018 observing season. During the austral summer of 2018-19, we tested the feasibility of using BICEP3 to observe the CMB at a low elevation at the South Pole. Due to operational constraints, we had to use a flat mirror to direct the beams to the low elevation range. We obtained additional data at the end of the 2019 winter observing season. We present the temperature and polarization maps from this data set, which clearly shows the detection of the E mode polarization. This potentially opens an opportunity to cover an extended patch of the sky at the South Pole. If the primordial B-mode is detected at the main observing field, probing larger areas will reduce sample variance. Larger observing field is also important to study the non-Gaussianity and decorrelation of the foregrounds. An interesting patch in this extended region is the CMB Cold Spot, whose origin is still in question. The possibility of testing polarization anomaly deviating from the standard Gaussian fluctuation around the Cold Spot is discussed.
Download or read book SPT 3G written by and published by . This book was released on 2014 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of E mode Polarization and Temperature E mode Correlation in the Cosmic Microwave Background from 100 Square Degrees of SPTPOL Data written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, we present measurements of $E$-mode polarization and temperature-$E$-mode correlation in the cosmic microwave background (CMB) using data from the first season of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope (SPT). The observations used in this work cover 100~\sqdeg\ of sky with arcminute resolution at $150\, $GHz. We also report the $E$-mode angular auto-power spectrum ($EE$) and the temperature-$E$-mode angular cross-power spectrum ($TE$) over the multipole range $500
Download or read book A Measurement of the Cosmic Microwave Background Gravitational Lensing Potential from 100 Square Degrees of SPTpol Data written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, we present a measurement of the cosmic microwave background (CMB) gravitational lensing potential using data from the first two seasons of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope. The observations used in this work cover 100 deg2 of sky with arcminute resolution at 150 GHz. Using a quadratic estimator, we make maps of the CMB lensing potential from combinations of CMB temperature and polarization maps. We combine these lensing potential maps to form a minimum-variance (MV) map. The lensing potential is measured with a signal-to-noise ratio of greater than one for angular multipoles between $100\lt L\lt 250$. This is the highest signal-to-noise mass map made from the CMB to date and will be powerful in cross-correlation with other tracers of large-scale structure. We calculate the power spectrum of the lensing potential for each estimator, and we report the value of the MV power spectrum between $100\lt L\lt 2000$ as our primary result. We constrain the ratio of the spectrum to a fiducial [Lambda]CDM model to be AMV = 0.92 ± 0.14 (Stat.) ± 0.08 (Sys.). Restricting ourselves to polarized data only, we find APOL = 0.92 ± 0.24 (Stat.) ± 0.11 (Sys.). This measurement rejects the hypothesis of no lensing at $5.9\sigma $ using polarization data alone, and at $14\sigma $ using both temperature and polarization data.
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 Inflationary Cosmology written by Martin Lemoine and published by Springer. This book was released on 2007-10-12 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: Some 25 years after the birth of inflationary cosmology, this volume sets out to provide both an authoritative and pedagogical introduction and review of the current state of the field. Readers learn about the arguments supporting the many different scenarios of cosmic inflation. Articles are written by eminent scientists, many of whom have made pioneering contributions to the field of inflationary cosmology.
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 A Measurement of the Cosmic Microwave Background Gravitational Lensing Potential and Its Power Spectrum from 500 Deg2 of SPTpol Data written by Laura Monica Mocanu and published by . This book was released on 2017 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 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 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 A Measurement of Secondary Cosmic Microwave Background Anisotropies from the 2500 square degree SPT SZ Survey written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present measurements of secondary cosmic microwave background (CMB) anisotropies and cosmic infrared background (CIB) fluctuations using data from the South Pole Telescope (SPT) covering the complete 2540 deg(2) SPT-SZ survey area. Data in the three SPT-SZ frequency bands centered at 95, 150, and 220 GHz, are used to produce six angular power spectra (three single-frequency auto-spectra and three cross-spectra) covering the multipole range 2000 l
