The Atacama Cosmology Telescope: Microwave Intensity and Polarization
  Maps of the Galactic Center
  We present arcminute-resolution intensity and polarization maps of the
Galactic center made with the Atacama Cosmology Telescope (ACT). The maps cover
a 32 deg$^2$ field at 98, 150, and 224 GHz with $\vert l\vert\le4^\circ$,
$\vert b\vert\le2^\circ$. We combine these data with Planck observations at
similar frequencies to create coadded maps with increased sensitivity at large
angular scales. With the coadded maps, we are able to resolve many known
features of the Central Molecular Zone (CMZ) in both total intensity and
polarization. We map the orientation of the plane-of-sky component of the
Galactic magnetic field inferred from the polarization angle in the CMZ,
finding significant changes in morphology in the three frequency bands as the
underlying dominant emission mechanism changes from synchrotron to dust
emission. Selected Galactic center sources, including Sgr A*, the Brick
molecular cloud (G0.253+0.016), the Mouse pulsar wind nebula (G359.23-0.82),
and the Tornado supernova remnant candidate (G357.7-0.1), are examined in
detail. These data illustrate the potential for leveraging ground-based Cosmic
Microwave Background polarization experiments for Galactic science.
