Browsing by Subject "CMB"
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Item The Astrophysics of Dust Polarization(2015) Boulanger, FrancoisThe Planck satellite has produced the first whole sky map of polarization|at sub-mm and mm wavelengths. This is an immense step forward from|earlier polarization observations of Galactic dust. The data is revealing a new|sky we have started to explore. For the first time, we have the data needed to characterize the structure of the Galactic magnetic field and its coupling with interstellar matter and turbulence, in the diffuse interstellar medium and molecular clouds. Our analysis of the data also involves the characterization of the polarization properties of dust. I will introduce the science questions we are investigating and review our published results. I will connect what we are learning on the astrophysics of dust polarization to the structure of the dusty polarized screen to CMB polarization at high Galactic latitudes.Item B-mode Polarization Results from the BICEP / Keck Array series and status of Keck Array and BICEP3(2015) Kovac, John; Kovac, JohnItem Bolometric detectors for EBEX: a balloon-borne cosmic microwave background polarimeter.(2009-12) Hubmayr, JohannesWe discuss the design and performance of arrays of millimeter-wave, bolometeric detectors for EBEX, the E and B Experiment. EBEX is a balloon-borne telescope designed to measure the polarization in the cosmic microwave background (CMB) radiation with 8 arc-minute resolution at 150, 250 and 410 GHz during a 14-day long duration balloon flight in Antarctica. On June 11, 2009 EBEX launched an engineering test flight from NASA's Columbia Scientific Ballooning Facility (CSBF) achieving 10 hours at float altitudes of 115,000 ft. EBEX is the first experiment to successfully operate transition edge sensor (TES) bolometers readout by superconducting quantum interference devices (SQUIDs) from a balloon platform. We present the EBEX instrument design, review TES bolometer and SQUID theory of operation and elaborate on frequency domain multiplexing. Following the analysis of the detector and readout system, we detail measurements that characterize the bolometers and conclude with a discussion of the EBEX receiver optical efficiency and in-flight bolometer loading during the engineering flight.Item Calibration and design of the E and B EXperiment (EBEX) cryogenic receiver(2014-08) Zilic, Kyle ThomasI discuss the design, construction, and calibration of the E \& B EXperiment (EBEX), a balloon-borne telescope designed to measure the B-mode polarization anisotropy of the cosmic microwave background (CMB). EBEX observes the sky with 8 arcmin resolution in three frequency bands centered on 150, 250, and 410 GHz, with over 1,500 detectors. Polarimetry is performed through use of a continuously rotating achromatic half-wave plate with fixed wire-grid polarizer. The experiment was designed to detect the gravitational-lensed B-mode signal and detect or set an upper limit for the inflationary B-mode signal. In this thesis, I describe the design and structure of various subsystems of the EBEX receiver and predict their experimental performance. Several calibrating instrumental response experiments are described and the results reported and compared to predictions. A brief review of the 2012-2013 long duration balloon (LDB) flight from McMurdo Station, Antarctica, is provided and a summary of the receiver performance during flight characterized.Item Calibration of the E and B EXperiment (EBEX), a balloon-borne cosmic microwave background polarimeter.(2009-10) Polsgrove, Daniel EdwardWe discuss pre-flight calibration of the E and B EXperiment (EBEX), a balloon-borne telescope designed to measure the B-mode polarization anisotropy of the cosmic microwave background (CMB). EBEX will observe the sky with 8' resolution in each of three bands centered on 150, 250 and 410 GHz. Employing over 1,400 detectors and performing polarimetry through a continuously rotating half-wave plate with fixed wire-grid polarizer, we expect to detect the B-mode signal or set a new upper limit one order of magnitude below the current value. In this thesis we describe a set of ground-based experiments devised for calibrating instrumental response to incident millimeter-wave flux with varying spectral and polarization properties. We chronicle the design, construction and execution of these experiments, along with preliminary results from tests executed prior to our North American (NA) test flight which originated at the Columbia Scientific Ballooning Facility, Ft Sumner, NM in June 2009. A brief review of this inaugural flight is provided, as is a synopsis of our current plan for a comprehensive calibration strategy to be implemented in conjunction with a future long duration balloon (LDB) flight over Antarctica.Item Constraining Fundamental Physics with Planck(2015) Rocha, GracaIn this talk we will present constraints on the temporal and spatial variation of fundamental constants such as fine structure constant, α, mass of the electron, $m_e$. etc. and investigate the degeneracies with cosmological parameters such as $H_0$Item Control of Systematics for the Primordial Inflation Explorer (PIXIE)(2015) Fixsen, DaleTalk will include an examination of systematic effects of emission from mirrors, calibrator, grids and other areas within the PIXIE instrument. The systematic effects of detector non-ideality and asymmetry will also be presented. These show that the residual systematic effects do not jeopardize either the polarization or spectrum measurements and that there are sufficient safeguards to find and calibrate out the most likely errors.Item COrE+ The Cosmic Origins Explorer A proposal for ESA's M4 space mission(2015) Delabrouille, JacquesItem Cosmology from the Planck 2- and 4-pt functions(2015) Challinor, AnthonyI review constraints on cosmological parameters from the Planck 2014 temperature and polarization data. Particular emphasis will be given to the extraction and interpretation of the effects of weak gravitational lensing.Item Cosmology Large Angular Scale Surveyor(2015) Eimer, JosephThe Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the imprint of gravitational waves from inflation in the polarization of the cosmic microwave background. CLASS is a multi-frequency array of four telescopes to be deployed in the Atacama Desert in Chile. From this site, CLASS will observe 70% of the sky at four frequency bands centered at 38, 93, 148, and 217 GHz - designed to straddle the full-sky galactic foreground minimum. The large survey area enables CLASS to characterize the B-mode and E-mode power spectra on both the reionization and recombination scales. Simulations including the presence of foregrounds suggest the CLASS strategy of combining large sky coverage, control of systematic errors, signal stability, and high sensitivity will allow detection of the tensor-to-scalar ratio down to the level of r=0.01 and enable cosmic-variance-limited measurements of the optical depth to reionization. In this talk, I present an overview of the CLASS strategy for measuring the E-modes and B-modes at the largest angular scales and give an update on the project status.Item Did m2φ2 bite the dust? A closer look at ns and r(2015) Rlauger, RaphaelI will review measurements of the angular power spectrum of temperature perturbations from Planck data by the Planck collaboration and by Renee Hlozek, David Spergel and myself and will discuss the small differences in the scalar spectral index between the two. I will then combine these measurements with the recent measurement of the polarization of the cosmic microwave background by BICEP2 as well as the measurements of polarized emission from dust by the Planck collaboration to derive the current (but soon outdated) constraints on the spectral index of scalar perturbations and the amount of primordial gravitational waves. I will show that the data now disfavors the simplest model of inflation at 2-3 sigma depending on the choice of likelihood for the temperature data.Item Did m2φ2 bite the dust? A closer look at ns and r(2015) Flauger, RaphaelI will review measurements of the angular power spectrum of temperature perturbations from Planck data by the Planck collaboration and by Renee Hlozek, David Spergel and myself and will discuss the small differences in the scalar spectral index between the two. I will then combine these measurements with the recent measurement of the polarization of the cosmic microwave background by BICEP2 as well as the measurements of polarized emission from dust by the Planck collaboration to derive the current (but soon outdated) constraints on the spectral index of scalar perturbations and the amount of primordial gravitational waves. I will show that the data now disfavors the simplest model of inflation at 2-3 sigma depending on the choice of likelihood for the temperature data.Item Dusty Universe Mapped by Herschel and CIB in arcminute-scale CMB (and TIME-Pilot to JCMT)(2015) Cooray, AsanthaItem LSPE the Large‐Scale Polarization Explorer(2015) de Bernardis, PaoloThe LSPE is a balloon-borne mission aimed at measuring the polarization of the Cosmic Microwave Background (CMB) at large angular scales, and in particular to constrain the curl component of CMB polarization (B-modes) produced by tensor perturbations generated during cosmic inflation, in the very early universe. Its primary target is the detection of the power spectrum of B-modes at multipoles covering both the reionization peak and the recombination peak, with a sensitivity corresponding to r = 0.02, at 99.7% confidence. A second target is to produce wide maps of foreground polarization generated in our Galaxy by synchrotron emission and interstellar dust emission. These will be important to map Galactic magnetic fields and to study the properties of ionized gas and of diffuse interstellar dust in our Galaxy. The mission is optimized for large angular scales, with coarse angular resolution (around 1.5 degrees FWHM), and wide sky coverage (25% of the sky). The payload will fly in a circumpolar long duration balloon mission during the polar night. Using the Earth as a giant solar shield, the instrument will spin in azimuth, observing a large fraction of the northern sky. The payload will host two instruments. An array of coherent polarimeters using cryogenic HEMT amplifiers will survey the sky at 43 and 90 GHz. An array of bolometric polarimeters, using large throughput multi-mode bolometers and rotating Half Wave Plates (HWP), will survey the same sky region in three bands at 140, 220 and 240 GHz. The wide frequency coverage will allow optimal control of the polarized foregrounds, with comparable angular resolution at all frequencies.Item MKIDs for CMB Studies(2015-01) Johnson, BradItem Odd Tensor Modes from Inflation(2015) Sorbo, LorenzoThe existence of a primordial spectrum of gravitational waves is a generic prediction of inflation. Here I will discuss how the coupling of a pseudoscalar inflaton to a gauge field can induce, in a two-step process, gravitational waves with unusual properties such as: (i) a net chirality (ii) a blue spectrum (iii) being detectable in the (relatively) near future by ground-based gravitational interferometers (iv) large nongaussianities even if the scalar perturbations are approximately gaussianItem Optical Designs and Antireflection Coatings for CMB Instruments(2022-02) Young, KarlThe cosmic microwave background (CMB) is one of the richest observables in cosmology. The B-mode polarization pattern is of particular interest as a direct probe of inflation. CMB polarization measurements provide additional cosmological information, such as the reionization optical depth, as well as particle physics information, such asthe sum of neutrino masses. Measuring the CMB polarization requires sensitive and stable mm-wave polarimeters. I worked to improve the optical design, antireflection coatings, and bolometers used in these polarimeters. I designed and analyzed Gregorian, Crossed, and Open Dragone CMB telescopes as a member of the EBEX, CORE, and PICO projects. The Open Dragone I developed for PICO is the first use of this optical system in a CMB instrument design. It provides a similar field of view to the Crossed Dragone used in CORE, while avoiding the far sidelobe issues. To facilitate the design process, I developed a white noise only, end-to-end sensitivity model for CMB instruments. This model includes correlated Bose photon noise between tightly packed pixels and the effects of multichroic pixels. I also developed prototype antireflection coatings on silicon, sapphire, and alumina using laser machining and dicing saws to produce sub-wavelength structures. These prototype coatings are cryogenically robust, low loss, have broad bandwidth (∆ν/νC = 55% on alumina), and illustrate a path to coatings on large, > 10 cm, lenses with ∆ν/νC ≈ 150%. Finally, as part of the EBEX project, I measured the optical time constants of flight bolometers and the optical efficiency of new, low thermal conductance, G = 9 pW/K, bolometers developed for future balloon-borne or space-based CMB instruments. Overall, my work has contributed to the newest generation of high sensitivity CMB polarimeters which will probe the earliest moments and fundamental properties of the Universe.Item PLANCK 2015 OVERVIEW & SYSTEMATICS(2015) Lawrence, CharlesI will give an overview of the Planck 2015 results and discuss the most important systematics affecting the two instrumentsItem Planck Simulations(2015-01) Borrill, JulianSimulations play a critical role in CMB experiments, including optimizing instrument design and deployment, validating and verifying data analysis algorithms and implementations, and debiasing and uncertainty quantification of the analysis results. Generating simulation sets also poses significant challenges, both in ensuring that they faithfully reproduce the critical characteristics of an experimental dataset, and in optimizing their generating to allow for the production of very large ensembles of realizations for Monte Carlo analyses. In this talk I will describe these challenges in the context of the simulation pipeline used in support of the 2nd Planck data release, outline the resulting dataset and its possible extension to support post-Planck experiments, and comment on the developments that will be needed for the next generation of mission-class CMB experiments such as CMB-S4, LiteBIRD and COrE+.