Planck Pre-Launch Status: the Planck-LFI Programme N
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
CMB Telescopes and Optical Systems to Appear In: Planets, Stars and Stellar Systems (PSSS) Volume 1: Telescopes and Instrumentation
CMB Telescopes and Optical Systems To appear in: Planets, Stars and Stellar Systems (PSSS) Volume 1: Telescopes and Instrumentation Shaul Hanany ([email protected]) University of Minnesota, School of Physics and Astronomy, Minneapolis, MN, USA, Michael Niemack ([email protected]) National Institute of Standards and Technology and University of Colorado, Boulder, CO, USA, and Lyman Page ([email protected]) Princeton University, Department of Physics, Princeton NJ, USA. March 26, 2012 Abstract The cosmic microwave background radiation (CMB) is now firmly established as a funda- mental and essential probe of the geometry, constituents, and birth of the Universe. The CMB is a potent observable because it can be measured with precision and accuracy. Just as importantly, theoretical models of the Universe can predict the characteristics of the CMB to high accuracy, and those predictions can be directly compared to observations. There are multiple aspects associated with making a precise measurement. In this review, we focus on optical components for the instrumentation used to measure the CMB polarization and temperature anisotropy. We begin with an overview of general considerations for CMB ob- servations and discuss common concepts used in the community. We next consider a variety of alternatives available for a designer of a CMB telescope. Our discussion is guided by arXiv:1206.2402v1 [astro-ph.IM] 11 Jun 2012 the ground and balloon-based instruments that have been implemented over the years. In the same vein, we compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). CMB interferometers are presented briefly. We con- clude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and Planck, to demonstrate a remarkable evolution in design, sensitivity, resolution, and complexity over the past thirty years. -
Small-Scale Anisotropies of the Cosmic Microwave Background: Experimental and Theoretical Perspectives
Small-Scale Anisotropies of the Cosmic Microwave Background: Experimental and Theoretical Perspectives Eric R. Switzer A DISSERTATION PRESENTED TO THE FACULTY OF PRINCETON UNIVERSITY IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY RECOMMENDED FOR ACCEPTANCE BY THE DEPARTMENT OF PHYSICS [Adviser: Lyman Page] November 2008 c Copyright by Eric R. Switzer, 2008. All rights reserved. Abstract In this thesis, we consider both theoretical and experimental aspects of the cosmic microwave background (CMB) anisotropy for ℓ > 500. Part one addresses the process by which the universe first became neutral, its recombination history. The work described here moves closer to achiev- ing the precision needed for upcoming small-scale anisotropy experiments. Part two describes experimental work with the Atacama Cosmology Telescope (ACT), designed to measure these anisotropies, and focuses on its electronics and software, on the site stability, and on calibration and diagnostics. Cosmological recombination occurs when the universe has cooled sufficiently for neutral atomic species to form. The atomic processes in this era determine the evolution of the free electron abundance, which in turn determines the optical depth to Thomson scattering. The Thomson optical depth drops rapidly (cosmologically) as the electrons are captured. The radiation is then decoupled from the matter, and so travels almost unimpeded to us today as the CMB. Studies of the CMB provide a pristine view of this early stage of the universe (at around 300,000 years old), and the statistics of the CMB anisotropy inform a model of the universe which is precise and consistent with cosmological studies of the more recent universe from optical astronomy. -
Cosmic Microwave Background
1 29. Cosmic Microwave Background 29. Cosmic Microwave Background Revised August 2019 by D. Scott (U. of British Columbia) and G.F. Smoot (HKUST; Paris U.; UC Berkeley; LBNL). 29.1 Introduction The energy content in electromagnetic radiation from beyond our Galaxy is dominated by the cosmic microwave background (CMB), discovered in 1965 [1]. The spectrum of the CMB is well described by a blackbody function with T = 2.7255 K. This spectral form is a main supporting pillar of the hot Big Bang model for the Universe. The lack of any observed deviations from a 7 blackbody spectrum constrains physical processes over cosmic history at redshifts z ∼< 10 (see earlier versions of this review). Currently the key CMB observable is the angular variation in temperature (or intensity) corre- lations, and to a growing extent polarization [2–4]. Since the first detection of these anisotropies by the Cosmic Background Explorer (COBE) satellite [5], there has been intense activity to map the sky at increasing levels of sensitivity and angular resolution by ground-based and balloon-borne measurements. These were joined in 2003 by the first results from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP)[6], which were improved upon by analyses of data added every 2 years, culminating in the 9-year results [7]. In 2013 we had the first results [8] from the third generation CMB satellite, ESA’s Planck mission [9,10], which were enhanced by results from the 2015 Planck data release [11, 12], and then the final 2018 Planck data release [13, 14]. Additionally, CMB an- isotropies have been extended to smaller angular scales by ground-based experiments, particularly the Atacama Cosmology Telescope (ACT) [15] and the South Pole Telescope (SPT) [16]. -
A Bit of History Satellites Balloons Ground-Based
Experimental Landscape ● A Bit of History ● Satellites ● Balloons ● Ground-Based Ground-Based Experiments There have been many: ABS, ACBAR, ACME, ACT, AMI, AMiBA, APEX, ATCA, BEAST, BICEP[2|3]/Keck, BIMA, CAPMAP, CAT, CBI, CLASS, COBRA, COSMOSOMAS, DASI, MAT, MUSTANG, OVRO, Penzias & Wilson, etc., PIQUE, Polatron, Polarbear, Python, QUaD, QUBIC, QUIET, QUIJOTE, Saskatoon, SP94, SPT, SuZIE, SZA, Tenerife, VSA, White Dish & more! QUAD 2017-11-17 Ganga/Experimental Landscape 2/33 Balloons There have been a number: 19 GHz Survey, Archeops, ARGO, ARCADE, BOOMERanG, EBEX, FIRS, MAX, MAXIMA, MSAM, PIPER, QMAP, Spider, TopHat, & more! BOOMERANG 2017-11-17 Ganga/Experimental Landscape 3/33 Satellites There have been 4 (or 5?): Relikt, COBE, WMAP, Planck (+IRTS!) Planck 2017-11-17 Ganga/Experimental Landscape 4/33 Rockets & Airplanes For example, COBRA, Berkeley-Nagoya Excess, U2 Anisotropy Measurements & others... It’s difficult to get integration time on these platforms, so while they are still used in the infrared, they are no longer often used for the http://aether.lbl.gov/www/projects/U2/ CMB. 2017-11-17 Ganga/Experimental Landscape 5/33 (from R. Stompor) Radek Stompor http://litebird.jp/eng/ 2017-11-17 Ganga/Experimental Landscape 6/33 Other Satellite Possibilities ● US “CMB Probe” ● CORE-like – Studying two possibilities – Discussions ongoing ● Imager with India/ISRO & others ● Spectrophotometer – Could include imager – Inputs being prepared for AND low-angular- the Decadal Process resolution spectrophotometer? https://zzz.physics.umn.edu/ipsig/ -
The Primordial Inflation Explorer (PIXIE)
The Primordial Inflation Explorer (PIXIE) Alan Koguta, Jens Chlubab, Dale J. Fixsenc,StephanMeyerd,andDavidSpergele aCode 665, NASA Goddard Space Flight Center, Greenbelt, MD USA 20771 bJodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, Manchester M13 9PL, UK cUniversity of Maryland, College Park MD USA dDept of Astronomy & Astrophysics, University of Chicago, Chicago, IL, USA eDept of Astrophysical Sciences, Princeton University, Princeton, NJ, USA 08544 ABSTRACT The Primordial Inflation Explorer is an Explorer-class mission to open new windows on the early universe through measurements of the polarization and absolute frequency spectrum of the cosmic microwave background. PIXIE will measure the gravitational-wave signature of primordial inflation through its distinctive imprint in linear polarization, and characterize the thermal history of the universe through precision measurements of distortions in the blackbody spectrum. PIXIE uses an innovative optical design to achieve background-limited sensitivity in 400 spectral channels spanning over 7 octaves in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded non-imaging optics feed a polarizing Fourier Transform Spectrometer to produce a set of interference fringes, proportional to the di↵erence spectrum between orthogonal linear polarizations from the two input beams. Multiple levels of symmetry and signal modulation combine to reduce systematic errors to negligible levels. PIXIE will map the full sky in Stokes I, Q, and U parameters with angular resolution 2.6◦ and sensitivity 70 nK per 1◦ square pixel. The principal science goal is the detection and characterization of linear 3 polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r<10− at 5 standard deviations. -