3d Cmz. I. Central Molecular Zone Overview

The Central Molecular Zone (CMZ) is the largest reservoir of dense molecular gas in the Galaxy and is heavily obscured in the optical and near-IR. We present an overview of the far-IR dust continuum, where the molecular clouds are revealed, provided by Herschel in the inner 40 degrees (divided by l divided by < 20 degrees) of the Milky Way with a particular focus on the CMZ. We report a total dense gas (N(H-2) > 10(23) cm(-2)) CMZ mass of M-circle dot and confirm that there is a highly asymmetric distribution of dense gas, with about 70%-75% at positive longitudes. We create and publicly release complete fore/background-subtracted column density and dust temperature maps in the inner 40 degrees (divided by l divided by < 20 degrees) of the Galaxy. We find that the CMZ clearly stands out as a distinct structure, with an average mass per longitude that is at least 3x higher than the rest of the inner Galaxy contiguously from 18 > & ell; > -13. This CMZ extent is larger than previously assumed, but is consistent with constraints from velocity information. The inner Galaxy's column density peaks towards the SgrB2 complex with a value of about 2 x 10(24) cm(-2), and typical CMZ molecular clouds are about N(H-2) similar to 10(23) cm(-2). Typical CMZ dust temperatures range from similar to 12-35 K with relatively little variation. We identify a ridge of warm dust in the inner CMZ that potentially traces the base of the northern Galactic outflow seen with MEERKAT.