The Atacama Cosmology Telescope: Modeling Bulk Atmospheric Motion

Abstract

Fluctuating atmospheric emission is a dominant source of noise for ground-based millimeter-wave observations of the CMB temperature anisotropy at angular scales $\gtrsim 0.5^{\circ }$. We present a model of the atmosphere as a discrete set of emissive turbulent layers that move with respect to the observer with a horizontal wind velocity. After introducing a statistic derived from the time-lag dependent correlation function for detector pairs in an array, referred to as the pair-lag, we use this model to estimate the aggregate angular motion of the atmosphere derived from time-ordered data from the Atacama Cosmology Telescope (ACT). We find that estimates derived from ACT's CMB observations alone agree with those derived from satellite weather data that additionally include a height-dependent horizontal wind velocity and water vapor density. We also explore the dependence of the measured atmospheric noise spectrum on the relative angle between the wind velocity and the telescope scan direction. In particular, we find that varying the scan velocity changes the noise spectrum in a predictable way. Computing the pair-lag statistic opens up new avenues for understanding how atmospheric fluctuations impact measurements of the CMB anisotropy.

References in corpus (16)

• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• The Atacama Cosmology Telescope: The polarization-sensitive ACTPol instrument
• The Atacama Cosmology Telescope: Data Characterization and Map Making
• MOSE: optical turbulence and atmospherical parameters operational forecast at ESO ground-based sites. I: Overview and atmospherical parameters vertical stratification on [0-20] km
• The Impact of Atmospheric Fluctuations on Degree-scale Imaging of the Cosmic Microwave Background
• An Instrument For Investigation of the Cosmic Microwave Background Radiation at Intermediate Angular Scales
• Characterization of the Mid-Frequency Arrays for Advanced ACTPol
• The Atacama Cosmology Telescope: Calibration with WMAP Using Cross-Correlations
• Global Distribution of Water Vapor and Cloud Cover--Sites for High Performance THz Applications
• Parque Astronómico de Atacama: An ideal site for millimeter, submillimeter, and mid-infrared astronomy
• Modeling atmospheric emission for CMB ground-based observations
• Millimeter Wavelength Brightness Fluctuations of the Atmosphere Above the South Pole
• Twenty years of PWV measurements in the Chajnantor Area
• Measurements of tropospheric ice clouds with a ground-based CMB polarization experiment, POLARBEAR
• Two-year Cosmology Large Angular Scale Surveyor (CLASS) Observations: A First Detection of Atmospheric Circular Polarization at Q Band
• Advanced ACTPol TES Device Parameters and Noise Performance in Fielded Arrays

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• The Atacama Cosmology Telescope: DR6 Gravitational Lensing Map and Cosmological Parameters
• The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and its Implications for Structure Growth
• The conceptual design of the 50-meter Atacama Large Aperture Submillimeter Telescope (AtLAST)
• The Atacama Cosmology Telescope: Map-Based Noise Simulations for DR6
• The Atacama Cosmology Telescope: Measurement and Analysis of 1D Beams for DR4
• The Atacama Cosmology Telescope: DR6 Power Spectrum Foreground Model and Validation
• Measurement and Modeling of Polarized Atmosphere at the South Pole with SPT-3G
• The Simons Observatory: Beam characterization for the Small Aperture Telescopes
• The Atacama Cosmology Telescope: Quantifying Atmospheric Emission above Cerro Toco
• Simons Observatory Focal-Plane Module: Detector Re-biasing With Bias-step Measurements
• Energy Recovery System for Large Telescopes
• The Atacama Cosmology Telescope: Machine Learning Driven Tools for Detecting Millimeter Sources in Timestream Pre-processing