The QUIJOTE Experiment: Project Overview and First Results
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Analysis and Measurement of Horn Antennas for CMB Experiments
Analysis and Measurement of Horn Antennas for CMB Experiments Ian Mc Auley (M.Sc. B.Sc.) A thesis submitted for the Degree of Doctor of Philosophy Maynooth University Department of Experimental Physics, Maynooth University, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland. October 2015 Head of Department Professor J.A. Murphy Research Supervisor Professor J.A. Murphy Abstract In this thesis the author's work on the computational modelling and the experimental measurement of millimetre and sub-millimetre wave horn antennas for Cosmic Microwave Background (CMB) experiments is presented. This computational work particularly concerns the analysis of the multimode channels of the High Frequency Instrument (HFI) of the European Space Agency (ESA) Planck satellite using mode matching techniques to model their farfield beam patterns. To undertake this analysis the existing in-house software was upgraded to address issues associated with the stability of the simulations and to introduce additional functionality through the application of Single Value Decomposition in order to recover the true hybrid eigenfields for complex corrugated waveguide and horn structures. The farfield beam patterns of the two highest frequency channels of HFI (857 GHz and 545 GHz) were computed at a large number of spot frequencies across their operational bands in order to extract the broadband beams. The attributes of the multimode nature of these channels are discussed including the number of propagating modes as a function of frequency. A detailed analysis of the possible effects of manufacturing tolerances of the long corrugated triple horn structures on the farfield beam patterns of the 857 GHz horn antennas is described in the context of the higher than expected sidelobe levels detected in some of the 857 GHz channels during flight. -
La Radiación Del Fondo Cósmico De Microondas Abstracts
Simposio Internacional: La radiación del Fondo Cósmico de Microondas: mensajera de los orígenes del universo International Symposium: CMB Radiation: Messenger of the Origins of Our Universe Madrid, 6 de noviembre de 2014 Madrid, November 6, 2014 I The seeds of structure: A view of the Cosmic Microwave Background, Joseph Silk The shape of the universe as seen by Planck, Enrique Martínez-González Deciphering the beginnings of the universe with CMB polarization, Matías Zaldarriaga 30 years of Cosmic Microwave Background experiments in Tenerife: From temperature to polarization maps, Rafael Rebolo Cosmology from Planck: Do we need a new Physics?, Nazzareno Mandolesi FUNDACIÓN RAMÓN ARECES Simposio Internacional: La radiación del Fondo Cósmico de Microondas: mensajera de los orígenes del universo International Symposium: CMB Radiation: Messenger of the Origins of Our Universe Madrid, 6 de noviembre de 2014 Madrid, November 6, 2014 The seeds of structure: A view of the Cosmic Microwave Background, Joseph Silk One of our greatest challenges is understanding the origin of the structure of the universe.I will describe how the fossil radiation from the beginning of the universe, the cosmic microwave background, has provided a window for probing the initial conditions from which structure evolved. Infinitesimal variations in temperature on the sky, first discovered in 1992, provide the fossil fluctuations that seeded the formation of the galaxies. The cosmic microwave background radiation has now been mapped with ground-based, balloon-borne and satellite telescopes. These provide the basis for our current ``precision cosmology'' in which the universe not only contains Dark Matter but also ``DarkEnergy'', which has accelerated its expansion exponentially in the last 4 billion years. -
A Bayesian Method for Point Source Polarisation Estimation D
A&A 651, A24 (2021) Astronomy https://doi.org/10.1051/0004-6361/202039741 & c ESO 2021 Astrophysics A Bayesian method for point source polarisation estimation D. Herranz1, F. Argüeso2,4, L. Toffolatti3,4, A. Manjón-García1,5, and M. López-Caniego6 1 Instituto de Física de Cantabria, CSIC-UC, Av. de Los Castros s/n, 39005 Santander, Spain e-mail: [email protected] 2 Departamento de Matemáticas, Universidad de Oviedo, C. Federico García Lorca 18, 33007 Oviedo, Spain 3 Departamento de Física, Universidad de Oviedo, C. Federico García Lorca 18, 33007 Oviedo, Spain 4 Instituto Universitario de Ciencias y Tecnologías Espaciales de Asturias (ICTEA), Escuela de Ingeniería de Minas, Materiales y Energía de Oviedo, C. Independencia 13, 33004 Oviedo, Spain 5 Departamento de Física Moderna, Universidad de Cantabria, 39005 Santander, Spain 6 ESAC, Camino Bajo del Castillo s/n, 28692 Villafranca del Castillo, Madrid, Spain Received 22 October 2020 / Accepted 2 March 2021 ABSTRACT The estimation of the polarisation P of extragalactic compact sources in cosmic microwave background (CMB) images is a very important task in order to clean these images for cosmological purposes –for example, to constrain the tensor-to-scalar ratio of primordial fluctuations during inflation– and also to obtain relevant astrophysical information about the compact sources themselves in a frequency range, ν ∼ 10–200 GHz, where observations have only very recently started to become available. In this paper, we propose a Bayesian maximum a posteriori approach estimation scheme which incorporates prior information about the distribution of the polarisation fraction of extragalactic compact sources between 1 and 100 GHz. -
Optimal Reconstruction of Cosmological Density Fields by Benjamin A. Horowitz a Dissertation Submitted in Partial Satisfaction O
Optimal Reconstruction of Cosmological Density Fields By Benjamin A. Horowitz Adissertationsubmittedinpartialsatisfactionofthe requirements for the degree of Doctor of Philosophy in Physics in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Uros Seljak, Chair Professor Aaron Parson Professor Martin White Fall 2019 Optimal Reconstruction of Cosmological Density Fields Copyright 2019 by Benjamin A. Horowitz 1 Abstract Optimal Reconstruction of Cosmological Density Fields by Benjamin A. Horowitz Doctor of Philosophy in Physics University of California, Berkeley Professor Uros Seljak, Chair Akeyobjectiveofmoderncosmologyistodeterminethecompositionanddistributionof matter in the universe. While current observations seem to match the standard cosmological model with remarkable precision, there remains tensions between observations as well as mysteries relating to the true nature of dark matter and dark energy. Despite the recent in- creased availability of cosmological data across a wide redshift, these tensions have remained or been further worsened. With the explosion of astronomical data in the coming decade, it has become increasingly critical to extract the maximum possible amount of information available across all available scales. As the available volume for analysis increases, we are no longer sample variance limited and existing summary statistics (as well as related estima- tors) need to be re-examined. Fortunately, parallel with the construction of these surveys there is significant development in the computational techniques used to analyze that data. Algorithmic developments over the past decade and expansion of computational resources allow large cosmological simulations to be run with relative simplicity and parallel theoretical developments motivate increased interest in recovering the underlying large scale structure of the universe beyond the power spectra. -
The Effect of a Scanning Flat Fold Mirror on a CMB B-Mode Experiment
The effect of a scanning flat fold mirror on a CMB B-mode experiment William F. Grainger, Chris E. North, Peter. A. R. Ade Astronomy Instrumentation Group, Cardiff University. (Dated: November 19, 2018) We investigate the possibility of using a flat-fold beam steering mirror for a CMB B-mode exper- iment. An aluminium flat-fold mirror is found to add ∼0.075% polarization, which varies in a scan synchronous way. Time-domain simulations of a realistic scanning pattern are performed, and the effect on the power-spectrum illustrated and a possible method of correction applied. I. INTRODUCTION a fiducal scan strategy and simulation pipeline. Results from this pipeline are then presented and discussed, along with other potential problems in Section IV. The prevailing ΛCDM cosmological model has been very successful in explaining many observations of the universe. However, inflation - exponential expansion II. METHOD within the first 10−35 s - has many uncertain details; indeed it lacks strong∼ confirmation. Inflationary models predict a background of gravity waves [1, 9, 20, 22, 23] For this investigation, we consider a horn fed receiver which produce a curl-like, or “B-mode” pattern of po- and compact range antenna (CRA), placed in a ground- larization on the cosmic microwave background (CMB) screen, nominally observing the horizon. The output on scales greater than 1◦, which cannot be produced by beam of the CRA is then steered to the sky with a single, density perturbations [11, 25]. The amplitude of this sig- flat, fold mirror. Although the flat mirror would be large; 4 4 m, such a system can be considered. -
The Thirty Gigahertz Instrument Receiver for the Q-U-I Joint Tenerife Experiment: Concept and Experimental Results Enrique Villa,1,A) Juan L
REVIEW OF SCIENTIFIC INSTRUMENTS 86, 024702 (2015) The thirty gigahertz instrument receiver for the Q-U-I Joint Tenerife experiment: Concept and experimental results Enrique Villa,1,a) Juan L. Cano,1 Jaime Cagigas,1 David Ortiz,2 Francisco J. Casas,2 Ana R. Pérez,1 Beatriz Aja,1 J. Vicente Terán,1 Luisa de la Fuente,1 Eduardo Artal,1 Roger Hoyland,3 and Ángel Mediavilla1 1Departamento Ingeniería de Comunicaciones, Universidad de Cantabria, Plaza de la Ciencia s/n, Santander 39005, Spain 2Instituto de Física de Cantabria, Avda. Los Castros s/n, Santander 39005, Spain 3Instituto de Astrofísica de Canarias, Vía Láctea s/n, La Laguna 38205, Spain (Received 12 December 2014; accepted 19 January 2015; published online 4 February 2015) This paper presents the analysis, design, and characterization of the thirty gigahertz instrument receiver developed for the Q-U-I Joint Tenerife experiment. The receiver is aimed to obtain polarization data of the cosmic microwave background radiation from the sky, obtaining the Q, U, and I Stokes parameters of the incoming signal simultaneously. A comprehensive analysis of the theory behind the proposed receiver is presented for a linearly polarized input signal, and the functionality tests have demonstrated adequate results in terms of Stokes parameters, which validate the concept of the receiver based on electronic phase switching. C 2015 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4907015] I. INTRODUCTION the moment right after the Big Bang.6 Among ground-based projects, QUIET7 and FARADAY8 have developed sensitive The Cosmic Microwave Background (CMB) is the ther- radiometers based on the schemes of previous receivers per- mal radiation from the Big Bang explosion, which fills the forming high-quality sky maps. -