The Atacama Cosmology Telescope: Data Characterization and Map Making
Creators: name: Dünner, Rolando
name: Hasselfield, Matthew
name: Marriage, Tobias A.
name: Sievers, Jon
name: Acquaviva, Viviana
name: Addison, Graeme E.
name: Ade, Peter A. R.
name: Aguirre, Paula
name: Amiri, Mandana
name: Appel, John William
name: Barrientos, L. Felipe
name: Battistelli, Elia S.
name: Bond, J. Richard
name: Brown, Ben
name: Burger, Bryce
name: Calabrese, Erminia
name: Chervenak, Jay
name: Das, Sudeep
name: Devlin, Mark J.
name: Dicker, Simon R.
name: Doriese, W. Bertrand
name: Dunkley, Joanna
name: Essinger-Hileman, Thomas
name: Fisher, Ryan P.
name: Gralla, Megan B.
name: Fowler, Joseph W.
name: Hajian, Amir
name: Halpern, Mark
name: Hernández-Monteagudo, Carlos
name: Hilton, Gene C.
name: Hilton, Matt
name: Hincks, Adam D.
name: Hlozek, Renée
name: Huffenberger, Kevin M.
name: Hughes, David H.
name: Hughes, John P.
name: Infante, Leopoldo
name: Irwin, Kent D.
name: Juin, Jean Baptiste
name: Kaul, Madhuri
name: Klein, Jeff
name: Kosowsky, Arthur
name: Lau, Judy M.
name: Limon, Michele
name: Lin, Yen-Ting
name: Louis, Thibaut
name: Lupton, Robert H.
name: Marsden, Danica
name: Martocci, Krista
name: Mauskopf, Phil
name: Menanteau, Felipe
name: Moodley, Kavilan
name: Moseley, Harvey
name: Netterfield, Calvin B.
name: Niemack, Michael D.
name: Nolta, Michael R.
name: Page, Lyman A.
name: Parker, Lucas
name: Partridge, Bruce
name: Quintana, Hernán
name: Reid, Beth
name: Sehgal, Neelima
name: Sherwin, Blake D.
name: Spergel, David N.
name: Staggs, Suzanne T.
name: Swetz, Daniel S.
name: Switzer, Eric R.
name: Thornton, Robert
name: Trac, Hy
name: Tucker, Carole
name: Warne, Ryan
name: Wilson, Grant
name: Wollack, Ed
name: Zhao, Yue
Publisher: name: arXiv
Year: 2012
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present a description of the data reduction and mapmaking pipeline used for the 2008 observing season of the Atacama Cosmology Telescope (ACT). The data presented here at 148 GHz represent 12% of the 90 TB collected by ACT from 2007 to 2010. In 2008 we observed for 136 days, producing a total of 1423 hours of data (11 TB for the 148 GHz band only), with a daily average of 10.5 hours of observation. From these, 1085 hours were devoted to a 850 deg^2 stripe (11.2 hours by 9.1 deg) centered on a declination of -52.7 deg, while 175 hours were devoted to a 280 deg^2 stripe (4.5 hours by 4.8 deg) centered at the celestial equator. We discuss sources of statistical and systematic noise, calibration, telescope pointing, and data selection. Out of 1260 survey hours and 1024 detectors per array, 816 hours and 593 effective detectors remain after data selection for this frequency band, yielding a 38% survey efficiency. The total sensitivity in 2008, determined from the noise level between 5 Hz and 20 Hz in the time-ordered data stream (TOD), is 32 micro-Kelvin sqrt{s} in CMB units. Atmospheric brightness fluctuations constitute the main contaminant in the data and dominate the detector noise covariance at low frequencies in the TOD. The maps were made by solving the least-squares problem using the Preconditioned Conjugate Gradient method, incorporating the details of the detector and noise correlations. Cross-correlation with WMAP sky maps, as well as analysis from simulations, reveal that our maps are unbiased at multipoles ell &gt; 300. This paper accompanies the public release of the 148 GHz southern stripe maps from 2008. The techniques described here will be applied to future maps and data releases.
description: 20 pages, 18 figures, 6 tables, an ACT Collaboration paper