JCMT Mapping of CO(3-2) in the Circumnuclear Region of M31

Abstract

We present a survey of CO(3-2) molecular line emission in the circumnuclear region of M31 with the James Clerk Maxwell Telescope (JCMT), aiming to explore the physical conditions of the molecular gas. Significant CO(3-2) lines are detected primarily along the so-called nuclear spiral, out to a projected galactocentric radius of 700 pc at a linear resolution of ~50 pc. We find that the velocity field of the molecular gas is in rough agreement with that of the ionized gas previously determined from optical observations. Utilizing existed CO(2-1) and CO(1-0) measurements in selected regions of the nuclear spiral, we derive characteristic intensity ratios of CO(3-2)/CO(2-1) and CO(3-2)/CO(1-0), which are both close to unity and are significantly higher than the typical intensity ratios in the disk. Such line ratios suggest high kinetic temperatures of the gas, which might be due to strong interstellar shocks prevalent in the circumnuclear region.

11 pages, 8 figure, accepted publication by MNRAS

References in corpus (3)

• An almost head-on collision as the origin of two off-centre rings in the Andromeda galaxy
• The JCMT Nearby Galaxies Legacy Survey I. Star Forming Molecular Gas in Virgo Cluster Spiral Galaxies
• Unravelling the mystery of the M31 bar

Cited by in corpus (6)

• XMM-Newton RGS spectroscopy of the M31 bulge. I: Evidences for a past AGN half a million years ago
• The HASHTAG project I. A Survey of CO(3-2) Emission from the Star Forming Disc of M31
• Large-scale Hydrodynamical Shocks as the Smoking Gun Evidence for a Bar in M31
• NOEMA Detection of Circumnuclear Molecular Gas in X-ray Weak Dual Active Galactic Nuclei: No Evidence for Heavy Obscuration
• CAHA/PPAK Integral-field Spectroscopic Observations of M81 -- I. Circumnuclear ionized gas
• A Herschel mapping of [C ii], [O i] and [O iii] lines from the circumnuclear region of M31