The Atacama Cosmology Telescope: Quantifying atmospheric emission above Cerro Toco
At frequencies below 1 Hz, fluctuations in atmospheric emission in the Chajnantor region in northern Chile are the primary source of interference for bolometric millimeter-wave observations. This paper focuses on characterizing the statistics of these fluctuations using measurements from the Atacama Cosmology Telescope (ACT) and the Atacama Pathfinder Experiment (APEX) water vapor radiometer. We show that the total precipitable water vapor (PWV) is not in general an accurate estimator of the level of fluctuations in millimeter-wave atmospheric emission. We also show that the microwave frequency spectrum of atmospheric fluctuations is in good agreement with predictions by the am code for frequency bands above 90 GHz. We introduce a new method for separating atmospheric and systematic fluctuations, allowing us to fit a robust atmospheric flat field, as well as to study in the atmosphere in greater detail than previous works. We present a direct measurement of the temporal outer scale of turbulence of ${\ensuremath{\tau}}_{0}\ensuremath{\approx}50\text{ }\text{ }\mathrm{s}$ corresponding to a spatial scale of ${L}_{0}\ensuremath{\approx}500\text{ }\text{ }\mathrm{m}$. Lastly, we show the variance of fluctuations in ACT's mm-wave bands correlate with the variance of fluctuations in PWV measured by APEX, even though the observatories are 6 km apart and observe different lines of sight.
Authors
- Sigurd Næss (ORCID: https://orcid.org/0000-0002-4478-7111)
- E. S. Battistelli (ORCID: https://orcid.org/0000-0001-5210-7625)
- Joshiwa van Marrewijk (ORCID: https://orcid.org/0000-0001-9830-3103)
- Jo Dunkley (ORCID: https://orcid.org/0000-0002-7450-2586)
- Rolando Dünner (ORCID: https://orcid.org/0000-0003-3892-1860)
- Adriaan J. Duivenvoorden (ORCID: https://orcid.org/0000-0003-2856-2382)
- Steve K. Choi (ORCID: https://orcid.org/0000-0002-9113-7058)
- Yuhan Wang (ORCID: https://orcid.org/0000-0002-8710-0914)
- Cristobál Sifón (ORCID: https://orcid.org/0000-0002-8149-1352)
- Yilun Guan (ORCID: https://orcid.org/0000-0002-1697-3080)
- Tony Mroczkowski (ORCID: https://orcid.org/0000-0003-3816-5372)
- Ricardo Bustos (ORCID: https://orcid.org/0000-0001-8468-9391)
- Edward J. Wollack (ORCID: https://orcid.org/0000-0002-7567-4451)
- Maria Salatino (ORCID: https://orcid.org/0000-0003-4006-1134)
- T. W. Morris (ORCID: https://orcid.org/0000-0002-5564-997X)
- Lyman A. Page
- Bruce Partridge
- Mark Halpern
- Michael D. Niemack
- Roberto Puddu (ORCID: https://orcid.org/0000-0002-2799-512X)
Institutions
- Pontificia Universidad Católica de Valparaíso (CL)
- Goddard Space Flight Center (US)
- University of British Columbia (CA)
- Haverford College (US)
- Pontificia Universidad Católica de Chile (CL)
- University of Oslo (NO)
- University of Toronto (CA)
- Princeton University (US)
- Cornell University (US)
- University of California System (US)
- Yale University (US)
- Universidad Católica de la Santísima Concepción (CL)
- Kavli Institute for Particle Astrophysics and Cosmology (US)
- Instituto de Física La Plata (AR)
- Stanford Synchrotron Radiation Lightsource (US)
- Flatiron Health (United States) (US)
- Flatiron Institute (US)
- National Synchrotron Light Source II
- Sapienza University of Rome (IT)
- Stanford University (US)
Publication Details
- Journal
- Physical review. D/Physical review. D.
- Published
- 2025-04-01
- DOI
- https://doi.org/10.1103/physrevd.111.082001
- Citations
- 2
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 2.31
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- Simons Foundation
- Princeton University
- University of Pennsylvania
- Compute Canada
- Government of Ontario
- Canada Foundation for Innovation
- University of Toronto
- University of British Columbia
- Agencia Nacional de Investigación y Desarrollo