Purpose of the Program

The central molecular zone in the inner galaxy was surveyed in [C II] emission using GREAT.

Principal Investigators

Rolf Güsten (MPIfR Bonn, Germany) and  Andrew Harris (University of Maryland, MD, USA)


05_0022, 06_0157, 06_0173, 83_0609, and GREAT Guaranteed Time

Proposal IDs and Data Access





Proposal Abstract

Context: Sgr C is a massive but relatively quiescent region at the western edge of the Galaxy’s Central Molecular zone (CMZ). Contrasting it with the far more active SgrB2 at the other side of the CMZ will explore the range of properties of massive clouds in the nuclei of normal galaxies.

Aims: We aim to add to our understanding of the Galactic center and galactic nuclei in general by searching for CO-dark dense neutral gas that may be streaming into the center from crossing x1-x2 orbits or associated with swept-up material from supernovae or colliding clouds.

Methods: We will trace 158μm[CII] and 63μm[OI] associated with dense neutral gas components that are missing in molecular line tracers. upGREAT provides an order of magnitude improvement in sensitivity over the Herschel-HIFI receivers, as well as probing lines Herschel- HIFI could not.

Anticipated results: Comparison of [C II], [O I], and complementary molecular observations with APEX will firmly establish the location and kinematics of all dense neutral gas components. This is also the second sub-project within a long-term project to produce a [C II] and [O I] data cube for the entire Central Molecular Zone (CMZ) with uniform sensitivity, velocity resolution, and sampling. A preliminary look at yesterday’s data from the first step, imaging SgrB2, shows unexpected results, and comparisons across the CMZ will be extremely interesting.

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