The connecting molecular ridge in the Galactic center

Abstract

We report new observations of multiple transitions of the CS molecular lines in the SgrA region of the Galactic center, at an angular resolution of 40" (=1.5 pc). The objective of this paper is to study the polar arc, which is a molecular ridge near the SgrA region, with apparent non-coplanar motions, and a velocity gradient perpendicular to the Galactic plane. With our high resolution dense-gas maps, we search for the base and the origin of the polar arc, which is expected to be embedded in the Galactic disk. We find that the polar arc is connected to a continuous structure from one of the disk ring/arm in both the spatial and velocity domains. This structure near SgrA* has high CS(J=4-3)/CS(J=2-1) ratios >1. That this structure has eluded detection in previous observations, is likely due to the combination of high excitation and low surface brightness temperature. We call this new structure the connecting ridge. We discuss the possible mechanism to form this structure and to lift the gas above the Galactic plane.

19 pages

References in corpus (16)

• Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
• Evidence for Ubiquitous Collimated Galactic-Scale Outflows along the Star-Forming Sequence at z~0.5
• The Starburst-Driven Molecular Wind in NGC 253 and the Suppression of Star Formation
• The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline
• The SAMI Galaxy Survey: Shocks and Outflows in a normal star-forming galaxy
• On the Formation of Compact Stellar Disks Around Sgr A*
• Detection of Widespread Hot Ammonia in the Galactic Center
• A Wide-area VLA Continuum Survey near the Galactic Center at 6 and 20 cm Wavelengths
• Infrared Tip of the Red Giant Branch and Distances to the Maffei/IC 342 Group
• SOFIA/FORCAST Imaging of the Circumnuclear Ring at the Galactic Center
• GBT Multiwavelength Survey of the Galactic Center Region
• ATCA Survey of Ammonia in the Galactic Center: The Temperatures of Dense Gas Clumps between SgrA* and SgrB2
• Self-Regulated Fueling of Galaxy Centers: Evidence for Star-Formation Feedback in IC342's Nucleus
• Very Large Array Observations of Galactic Center OH 1720 MHz Masers in Sagittarius A East and in the Circumnuclear Disk
• Radio Detection of A Candidate Neutron Star Associated with Galactic Center Supernova Remnant Sagittarius A East
• A New Perspective on the Radio Active Zone at The Galactic Center - Feedback from Nuclear Activities

Cited by in corpus (5)

• The Galactic center chimneys: The base of the multiphase outflow of the Milky Way
• Molecular Gas Feeding the Circumnuclear Disk of the Galactic Center
• Nuclear Spiral Shocks and Induced Gas Inflows in Weak Oval Potentials
• The Fossil Nuclear Outflow in the Central 30 pc of the Galactic Center
• The Chemistry and Kinematics of Two Molecular Clouds near Sagittarius A*