The Atacama cosmology telescope: Data characterization and mapmaking

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

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79 Scopus citations


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 hr of data (11 TB for the 148 GHz band only), with a daily average of 10.5 hr of observation. From these, 1085 hr were devoted to an 850 deg2 stripe (11.2 hr by 9.°1) centered on a declination of -52.°7, while 175 hr were devoted to a 280 deg2 stripe (4.5 hr by 4.°8) centered at the celestial equator. The remaining 163 hr correspond to calibration runs. We discuss sources of statistical and systematic noise, calibration, telescope pointing, and data selection. For the 148 GHz band, out of 1260 survey hours and 1024 detectors in the array, 816 hr and 593 effective detectors remain after data selection, 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 in cosmic microwave background 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. Simulations, as well as cross-correlations with Wilkinson Microwave Anisotropy Probe sky maps on large angular scales, reveal that our maps are unbiased at multipoles ℓ > 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.

Original languageEnglish (US)
Article number10
JournalAstrophysical Journal
Issue number1
StatePublished - Jan 1 2013

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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