Year: 2026
Type: preprint
Abstract: The Simons Observatory (SO) is a cosmic microwave background (CMB) survey experiment observing from an altitude of 5,200 m in the Atacama Desert in Chile. The SO Small Aperture Telescopes (SATs) will cover six spectral bands between 30 and 280 GHz primarily to search for evidence of primordial gravitational waves in the large angular scale $B$-modes of the CMB polarization. The first two Mid-Frequency (MF) SATs, operating in the 90 and 150 GHz frequency bands, began commissioning observations in late 2023, and we present the results of those observations here. Each MF SAT operates with approximately 9,400 biased transition-edge sensors (TES) at 1 mm of precipitable water vapor (PWV), representing a typical 80% yield. Planet observations confirm the telescope optics performance, calibrate the instrument response, and measure the end-to-end optical efficiency of the SATs. The realized instrument efficiencies are within the range expected based on instrument model predictions. In nominal observing conditions, the noise equivalent temperatures from both telescopes combined are $2.4~\mathrm{μK_{CMB}\sqrt{s}}$ at 90 GHz and $3.2~\mathrm{μK_{CMB}\sqrt{s}}$ at 150 GHz, substantially outperforming the baseline instantaneous sensitivity targets for the observatory.
Source: arXiv (Cornell University)
Authors: Harrington, Kathleen, Gerras, Remington, Galitzki, Nicholas, Day-Weiss, Samuel, Sueno, Yoshinori, Alford, Thomas, Randall, Michael J., Yamada, Kyohei, Silva-Feaver, Maximiliano, Crowley, Kevin, Adachi, Shunsuke, Adler, Alexandre E., Agrawal, Prakamya, Aiola, Simone, Alonso, David, Arnold, Kam, Azzoni, Susanna, Bazarko, Andrew, Bhimani, Sanah, Biquard, Simon, Bixler, Bryce, Borrow, Josh, Brown, Michael L., Calabrese, Erminia, Chinone, Yuji, Choi, Steve K., Dachlythra, Nadia, Devlin, Mark, Dicker, Simon, Dow, Peter N., Duff, Shannon M., Dunkley, Jo, Dunner, Rolando, Dutcher, Daniel, Bouhargani, Hamza El, Errard, Josquin, Foster, Allen, Ganga, Ken, Groh, John, Guan, Yilun, Gudmundsson, Jon E., Haridas, Saianeesh, Hasegawa, Masaya, Hasselfield, Matthew, Henderson, Shawn W., Hervías-Caimapo, Carlos, Hincks, Adam D., Hložek, Renée, Hubmayr, Johannes, Johnson, Bradley R., Kasai, Yutaro, Keating, Brian, Keller, Ben, Kisner, Theodore, Koopman, Brian J., Kusaka, Akito, Lee, Adrian, Lloyd, JB, Lonappan, Anto, Lungu, Marius, Mangu, Aashrita, McCrackan, Michael, McMahon, Jeff, Moore, Jenna, Morris, Thomas W., Nakata, Hironobu, Nati, Federico, Newburgh, Laura, Nguyen, David V., Orlowski-Scherer, John, Page, Lyman, Paraskevakos, Ioannis, Pinsonneault-Marotte, Tristan, Rosenberg, Erik, Sakurai, Yuki, Sathyanathan, Goureesankar, Satterthwaite, Thomas P., Seino, Yudai, Shaw, Elle, Simon, Sara M., Staggs, Suzanne T., Sugiyama, Junna, Suzuki, Junya, Takakura, Satoru, Tajima, Osamu, Thomas, Alex, Thomas, Daniel B., Tsan, Tran, Vavagiakis, Eve, Wang, Yuhan, Wilson, John
Institutions: Argonne National Laboratory, University of Chicago, University of Southern California, The University of Texas at Austin, Kavli Institute for the Physics and Mathematics of the Universe, Princeton University, The University of Tokyo, University of California San Diego, Flatiron Institute, University of Oxford, University of Manchester, University of Pennsylvania, University of California, Riverside, University of Virginia, National Institute of Standards and Technology, Pontificia Universidad Católica de Chile, Lawrence Berkeley National Laboratory, University of Toronto, Kyoto University, Cornell University, Space Sciences Laboratory, University of California, Berkeley, Simons Foundation, Yale University, Duke University, University of Milano-Bicocca, SLAC National Accelerator Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Suwa University of Science
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Princeton University, National Energy Research Scientific Computing Center, European Commission, Science Foundation Ireland, University of Toronto, Háskóli Íslands, Agencia Nacional de Investigación y Desarrollo, Office of Science, Natural Sciences and Engineering Research Council of Canada, Science and Technology Facilities Council, Japan Society for the Promotion of Science, High Energy Physics, Argonne National Laboratory, Fermilab
Awards: G102163711, G107546177, 形態情報処理にもとづく細胞形態変化の機構に関する研究, Simons Observatory:UK technology development and demonstration, G1313983767, G1664757510, SO:UK - A major UK contribution to Simons Observatory, G2011917337, G2110534122, G2287611682, G2296787436, G2376186588, G262962599, G2710870262, G2724668986, G3075337988, G4347000405, G498139845, G4998900716, G513797252, G5560389312, G6256534168, Mid-scale RI-2: Advanced Millimeter Survey Instrumentation in Chile, G6471802762, G6918803902, G7086350903, G790377542, G8459464503, G8581667079, G8755702448, CENTRO DE ASTROFISICA Y TECNOLOGIAS AFINES (CATA), G993149817
OpenAlex ID: W7214162934