The Atacama Cosmology Telescope: DR4 maps and cosmological parameters
Authors: Aiola Simone , Calabrese Erminia , Maurin Loïc , Naess Sigurd , Schmitt Benjamin L. , Abitbol Maximilian H. , Addison Graeme E. , Ade Peter A. R. , Alonso David , Amiri Mandana , Amodeo Stefania , Angile Elio , Austermann Jason E. , Baildon Taylor , Battaglia Nick , Beall James A. , Bean Rachel , Becker Daniel T. , Bond J Richard , Bruno Sarah Marie , Calafut Victoria , Campusano Luis E. , Carrero Felipe , Chesmore Grace E. , Cho Hsiao-mei , Choi Steve K. , Clark Susan E. , Cothard Nicholas F. , Crichton Devin , Crowley Kevin T. , Darwish Omar , Datta Rahul , Denison Edward V. , Devlin Mark J. , Duell Cody J. , Duff Shannon M. , Duivenvoorden Adriaan J. , Dunkley Jo , Dünner Rolando , Essinger-Hileman Thomas , Fankhanel Max , Ferraro Simone , Fox Anna E. , Fuzia Brittany , Gallardo Patricio A. , Gluscevic Vera , Golec Joseph E. , Grace Emily , Gralla Megan , Guan Yilun , Hall Kirsten , Halpern Mark , Han Dongwon , Hargrave Peter , Hasselfield Matthew , Helton Jakob M. , Henderson Shawn , Hensley Brandon , Hill J. Colin , Hilton Gene C. , Hilton Matt , Hincks Adam D. , Hložek Renée , Ho Shuay-Pwu Patty , Hubmayr Johannes , Huffenberger Kevin M. , Hughes John P. , Infante Leopoldo , Irwin Kent , Jackson Rebecca , Klein Jeff , Knowles Kenda , Koopman Brian , Kosowsky Arthur , Lakey Vincent , Li Dale , Li Yaqiong , Li Zack , Lokken Martine , Louis Thibaut , Lungu Marius , MacInnis Amanda , Madhavacheril Mathew , Maldonado Felipe , Mallaby-Kay Maya , Marsden Danica , McMahon Jeff , Menanteau Felipe , Moodley Kavilan , Morton Tim , Namikawa Toshiya , Nati Federico , Newburgh Laura , Nibarger John P. , Nicola Andrina , Niemack Michael D. , Nolta Michael R. , Orlowski-Sherer John , Page Lyman A. , Pappas Christine G. , Partridge Bruce , Phakathi Phumlani , Pisano Giampaolo , Prince Heather , Puddu Roberto , Qu Frank J. , Rivera Jesus , Robertson Naomi , Rojas Felipe , Salatino Maria , Schaan Emmanuel , Schillaci Alessandro , Sehgal Neelima , Sherwin Blake D. , Sierra Carlos , Sievers Jon , Sifon Cristobal , Sikhosana Precious , Simon Sara , Spergel David N. , Staggs Suzanne T. , Stevens Jason , Storer Emilie , Sunder Dhaneshwar D. , Switzer Eric R. , Thorne Ben , Thornton Robert , Trac Hy , Treu Jesse , Tucker Carole , Vale Leila R. , Engelen Alexander Van , Lanen Jeff Van , Vavagiakis Eve M. , Wagoner Kasey , Wang Yuhan , Ward Jonathan T. , Wollack Edward J. , Xu Zhilei , Zago Fernando , Zhu Ningfeng 
Published: December 2020

We present new arcminute-resolution maps of the Cosmic Microwave Background temperature and polarization anisotropy from the Atacama Cosmology Telescope, using data taken from 2013–2016 at 98 and 150 GHz. The maps cover more than 17,000 deg2, the deepest 600 deg2with noise levels below 10μK-arcmin. We use the power spectrum derived from almost 6,000 deg2of these maps to constrain cosmology. The ACT data enable a measurement of the angular scale of features in both the divergence-like polarization and the temperature anisotropy, tracing both the velocity and density at last-scattering. From these one can derive the distance to the last-scattering surface and thus infer the local expansion rate,H0. By combining ACT data with large-scale information fromWMAPwe measureH0=67.6± 1.1 km/s/Mpc, at 68% confidence, in excellent agreement with the independently-measuredPlancksatellite estimate (from ACT alone we findH0=67.9± 1.5 km/s/Mpc). The ΛCDM model provides a good fit to the ACT data, and we find no evidence for deviations: both the spatial curvature, and the departure from the standard lensing signal in the spectrum, are zero to within 1σ; the number of relativistic species, the primordial Helium fraction, and the running of the spectral index are consistent with ΛCDM predictions to within 1.5–2.2σ. We compare ACT,WMAP, andPlanckat the parameter level and find good consistency; we investigate how the constraints on the correlated spectral index and baryon density parameters readjust when adding CMB large-scale information that ACT does not measure. The DR4 products presented here will be publicly released on the NASA Legacy Archive for Microwave Background Data Analysis.