Atacama Cosmology Telescope: Constraints on cosmic birefringence

Toshiya Namikawa, Yilun Guan, Omar Darwish, Blake D. Sherwin, Simone Aiola, Nicholas Battaglia, James A. Beall, Daniel T. Becker, J. Richard Bond, Erminia Calabrese, Grace E. Chesmore, Steve K. Choi, Mark J. Devlin, Joanna Dunkley, Rolando Dünner, Anna E. Fox, Patricio A. Gallardo, Vera Gluscevic, Dongwon Han, Matthew HasselfieldGene C. Hilton, Adam D. Hincks, Reneé HloŽek, Johannes Hubmayr, Kevin Huffenberger, John P. Hughes, Brian J. Koopman, Arthur Kosowsky, Thibaut Louis, Marius Lungu, Amanda Macinnis, Mathew S. Madhavacheril, Maya Mallaby-Kay, Loïc Maurin, Jeffrey Mcmahon, Kavilan Moodley, Sigurd Naess, Federico Nati, Laura B. Newburgh, John P. Nibarger, Michael D. Niemack, Lyman A. Page, Frank J. Qu, Naomi Robertson, Alessandro Schillaci, Neelima Sehgal, Cristóbal Sifón, Sara M. Simon, David N. Spergel, Suzanne T. Staggs, Emilie R. Storer, Alexander Van Engelen, Jeff Van Lanen, Edward J. Wollack

Research output: Contribution to journalArticlepeer-review

54 Scopus citations


We present new constraints on anisotropic birefringence of the cosmic microwave background polarization using two seasons of data from the Atacama Cosmology Telescope covering 456 square degrees of sky. The birefringence power spectrum, measured using a curved-sky quadratic estimator, is consistent with zero. Our results provide the tightest current constraint on birefringence over a range of angular scales between 5 arc minutes and 9°. We improve previous upper limits on the amplitude of a scale-invariant birefringence power spectrum by a factor of between 2 and 3. Assuming a nearly massless axion field during inflation, our result is equivalent to a 2σ upper limit on the Chern-Simons coupling constant between axions and photons of gαγ<4.0×10-2/HI, where HI is the inflationary Hubble scale.

Original languageEnglish (US)
Article number083527
JournalPhysical Review D
Issue number8
StatePublished - Apr 15 2020

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


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