VERTICO: The Virgo Environment Traced In CO Survey
  We present the Virgo Environment Traced in CO (VERTICO) survey, a new effort
to map $^{12}$CO($2-1$), $^{13}$CO($2-1$), and C$^{18}$O($2-1$) in 51 Virgo
Cluster galaxies with the Atacama Compact Array, part of the Atacama Large
Millimeter/submillimeter Array (ALMA). The primary motivation of VERTICO is to
understand the physical mechanisms that perturb molecular gas disks, and
therefore star formation and galaxy evolution, in dense environments. This
first paper contains an overview of VERTICO's design and sample selection,
$^{12}$CO($2-1$) observations, and data reduction procedures. We characterize
global $^{12}$CO($2-1$) fluxes and molecular gas masses for the 49 detected
VERTICO galaxies, provide upper limits for the two non-detections, and produce
resolved $^{12}$CO($2-1$) data products (median resolution $= 8^{\prime\prime}
\approx 640~{\rm pc}$). Azimuthally averaged $^{12}$CO($2-1$) radial intensity
profiles are presented along with derived molecular gas radii. We demonstrate
the scientific power of VERTICO by comparing the molecular gas size--mass
scaling relation for our galaxies with a control sample of field galaxies,
highlighting the strong effect that radius definition has on this correlation.
We discuss the drivers of the form and scatter in the size--mass relation and
highlight areas for future work. VERTICO is an ideal resource for studying the
fate of molecular gas in cluster galaxies and the physics of environment-driven
processes that perturb the star formation cycle. Upon public release, the
survey will provide a homogeneous legacy dataset for studying galaxy evolution
in our closest cluster.
