ACT Data Products - Temperature Maps 2008-2010, 148 GHz & 217 GHz

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Description

These files contain the Atacama Cosmology Telescope (ACT) temperature maps of the southern and equatorial fields, observed during the 2008-2010 seasons, in the 148 GHz and 217 GHz bands, and produced for the ACT data release in February 2014.


The map boundaries are given below:

  Ra0 Ra1 Dec0 Dec1 Area ( >5000 hits per pixel)
AR1 Season 2 South: -74.7 142.2 -57.2 -48.0 854.54
AR1 Season 3 South (1): 53.8 120.7 -57.2 -48.0  
AR1 Season 3 South (2): 246.2 308.2 -57.2 -48.0 516.79 Combined
AR1 Season 4 South: 247.4 307.9 -57.2 -48.0 554.71
AR1 Season 3 Equa (1): -77.6 63.8 -2.4 2.5  
AR1 Season 3 Equa (2): 205.0 256.6 -2.4 2.5  
AR1 Season 3 Equa (3): 111.8 146.7 -2.4 2.5 822.16 Combined
AR1 Season 4 Equa (1): -63.9 65.4 -2.3 2.6  
AR1 Season 4 Equa (2): 111.7 257.8 -2.3 2.6 1072.7 Combined
AR2 Season 2 South: -65.7 137.4 -57.2 -48.0 872.62
AR2 Season 3 South: 55.0 116.0 -57.2 -48.1 511.31
AR2 Season 4 South (1): 52.1 120.0 -57.2 -48.1 565.85 Combined
AR2 Season 4 South (2): 246.8 306.4 -57.2 -48.1  
AR2 Season 3 Equa: -77.3 64.3 -2.3 2.4 554.86
AR2 Season 4 Equa: 110.0 296.5 -2.3 2.4 580.88

These maps are stored in the primary image arrays of FITS files. The units of the maps are uK-CMB, expressing deviations from the average measured intensity as equivalent fluctuations in the CMB in microkelvins.

The maps were computed by solving the maximum likelihood problem (inverse-noise-weighted average) for approximately 1012 calibrated data samples in the time domain.

The map-making process can be summarized as follows: The median level of each detector was removed together with a single array-wide slope across the 15-minute file; a pre-calculated data selection, calibration and pointing solution were applied (67% of the total raw data were left after data selection); 7 pre-computed dark modes were de-projected from each detector time stream; and the expected signal from the bright point sources using the ACT beam were also subtracted from them. Then the maps were solved for by minimizing chi-square over a noise model, which included correlated modes, cut data, with detector noises described by bins in the frequency domain. For maps with "src_free" in the title the flux from point sources has been removed, while maps with "summed" in the title have had the point source flux re-added to the maps. The resulting maps are expected to be unbiased at the scales of interest, and have shown to be consistent with WMAP at multipoles l > 300.

The 4way maps are used for the power spectrum analysis, where the data have been split into 4 subsets by TOD to enable cross correlation. The 1way maps are made from the entire subset together.

Back To ACT (MBAC): Products for the 2008-2010 Season at 148 GHz and 218 GHz

A service of the HEASARC and of the Astrophysics Science Division at NASA/GSFC
Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Alan P. Smale
LAMBDA Director: Dr. Thomas M. Essinger-Hileman
NASA Official: Dr. Thomas M. Essinger-Hileman
Web Curator: Mr. Michael R. Greason