Molecular Gas in the Inner 100 Parsecs of M51
Abstract
We report imaging of CO (2-1) emission in the nucleus of M51 at 1'' (47 pc) resolution. Molecular gas is found closely associated with the nuclear radio jet and the X-shaped dust absorption feature seen in the Hubble Space Telescope images. The CO emission lies along the side of the nuclear radio continuum ``jet.'' The strongest molecular emission is not symmetric in either position or velocity with respect to the nucleus--the dominant feature is at redshifted velocities and peaks 1'' to the west of the radio/optical nucleus. The CO (2-1) emission has an integrated flux implying a molecular gas mass of 107 Msolar for a standard Galactic giant molecular cloud CO-to-H2 conversion ratio, which is consistent with the total virial mass of the individual complexes. The redshifted CO emission is elongated with a deconvolved semimajor axis of 65 pc (1.38"). Assuming the molecular gas moves in circular orbit about the nucleus (defined by the point radio source), we find a dynamical mass of 2×108 Msolar at R>=47 pc with no correction for inclination. The molecular gas has sufficient density (>=105 cm-3) to collimate the radio jet and ionized outflow from the active galactic nucleus (AGN), and this gas may in fact be the reservoir of matter that supplies the AGN.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1998
- DOI:
- 10.1086/311128
- Bibcode:
- 1998ApJ...493L..63S
- Keywords:
-
- GALAXIES: INDIVIDUAL MESSIER NUMBER: M51;
- ISM: MOLECULES;
- Galaxies: Individual: Messier Number: M51;
- ISM: Molecules