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The Atacama Cosmology Telescope: Data Characterization and Map MakingWe 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% or the 90 TB collected by ACT from 2007 to 2010. In 2008 we observed for 136 days, producing a total of 142h of data (11 TB for the 148 GHz band only), with a daily average of 10.5 h of observation. From these, 108.5 h were devoted to 850 sq deg stripe (11.2 h by 9 deg.1) centered on a declination of -52 deg.7, while 175 h were devoted to a 280 square deg stripe (4.5 h by 4 deg.8) 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 h 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 muK square root of s in CMB units. Atmospheric brightness fluctuations constitute the main contaminant in the data and dominate the detector and noise covariance at low frequencies in the TOD. The maps were made by solving the lease 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 the our maps are unbiased at 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.
Document ID
20120015668
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Duenner, Rolando
(Pontificia Univ. Catolica de Chile Santiago, Chile)
Hasselfield, Matthew
(British Columbia Univ. Vancouver, British Columbia Canada)
Marriage, Tobias A.
(Princeton Univ. Princeton, NJ, United States)
Sievers, Jon
(Princeton Univ. Princeton, NJ, United States)
Acquaviva, Viviana
(Princeton Univ. Princeton, NJ, United States)
Addison, Graeme E.
(Oxford Univ. Oxford, United Kingdom)
Ade, Peter A. R.
(Cardiff Univ. United Kingdom)
Aguirre, Paula
(Pontificia Univ. Catolica de Chile Santiago, Chile)
Amiri, Mandana
(British Columbia Univ. Vancouver, British Columbia Canada)
Appel, John William
(Princeton Univ. Princeton, NJ, United States)
Barrientos, L. Felipe
(Pontificia Univ. Catolica de Chile Santiago, Chile)
Battistelli, Elia S.
(British Columbia Univ. Vancouver, British Columbia Canada)
Bond, J. Richard
(Toronto Univ. Ontario Canada)
Brown, Ben
(Pittsburgh Univ. Pittsburgh, PA, United States)
Burger, Bryce
(British Columbia Univ. Vancouver, British Columbia Canada)
Chervenak, Jay
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Calabrese, Erminia
(Oxford Univ. Oxford, United Kingdom)
Das, Sudeep
(Princeton Univ. Princeton, NJ, United States)
Devlin, Mark J.
(Pennsylvania Univ. Philadelphia, PA, United States)
Dicker, Simon R.
(Pennsylvania Univ. Philadelphia, PA, United States)
Doriese, W. Bertrand
(National Inst. of Standards and Technology Boulder, CO, United States)
Dunkley, Joanna
(Princeton Univ. Princeton, NJ, United States)
Essinger-Hileman, Thomas
(Princeton Univ. Princeton, NJ, United States)
Moseley, Harvey
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Wollack, Ed
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 26, 2013
Publication Date
January 1, 2012
Subject Category
Astronomy
Report/Patent Number
GSFC.JA.7097.2012
Funding Number(s)
CONTRACT_GRANT: NSF AST-0807790
CONTRACT_GRANT: DE-AC3-76SF00515
CONTRACT_GRANT: FONDAP 15010003
CONTRACT_GRANT: NSF AST-0408696
CONTRACT_GRANT: NSF PHY-0855887
CONTRACT_GRANT: NSF PHY-0114422
CONTRACT_GRANT: NSF PHY-1214379
CONTRACT_GRANT: FONDECYT-11100147
CONTRACT_GRANT: NSF AST-0965625
Distribution Limits
Public
Copyright
Public Use Permitted.
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