The Atacama Cosmology Telescope: Component-separated maps of CMB
  temperature and the thermal Sunyaev-Zel'dovich effect
  Optimal analyses of many signals in the cosmic microwave background (CMB)
require map-level extraction of individual components in the microwave sky,
rather than measurements at the power spectrum level alone. To date, nearly all
map-level component separation in CMB analyses has been performed exclusively
using satellite data. In this paper, we implement a component separation method
based on the internal linear combination (ILC) approach which we have designed
to optimally account for the anisotropic noise (in the 2D Fourier domain) often
found in ground-based CMB experiments. Using this method, we combine
multi-frequency data from the Planck satellite and the Atacama Cosmology
Telescope Polarimeter (ACTPol) to construct the first wide-area,
arcminute-resolution component-separated maps (covering approximately 2100 sq.
deg.) of the CMB temperature anisotropy and the thermal Sunyaev-Zel'dovich
(tSZ) effect sourced by the inverse-Compton scattering of CMB photons off hot,
ionized gas. Our ILC pipeline allows for explicit deprojection of various
contaminating signals, including a modified blackbody approximation of the
cosmic infrared background (CIB) spectral energy distribution. The cleaned CMB
maps will be a useful resource for CMB lensing reconstruction, kinematic SZ
cross-correlations, and primordial non-Gaussianity studies. The tSZ maps will
be used to study the pressure profiles of galaxies, groups, and clusters
through cross-correlations with halo catalogs, with dust contamination
controlled via CIB deprojection. The data products described in this paper are
available on LAMBDA.
