Context: Previous molecular gas observations at arcsecond-scale resolution of the Seyfert 2 galaxy
Aims: To image the putative circumnuclear molecular gas disk at sub-arcsecond resolution to better understand both the spatial distribution and kinematics of the molecular gas.
Methods: We carried out CO(2-1) and CO(1-0) line observations of the nuclear region of
Results: The high resolution images show no clear evidence of a disk, aligned nearly east-west and perpendicular to the radio jet axis, as suggested by previous observations, but show two separate features located on the eastern and western sides of the nucleus. The western feature shows an elongated structure along the jet and a good velocity correspondence with optical emission lines associated with the jet, suggesting that this feature is a jet-entrained gas. The eastern feature is elongated nearly east-west ending around the nucleus. A velocity gradient appears in the same direction with increasingly blueshifted velocities near the nucleus. This velocity gradient is in the opposite sense of that previously inferred for the putative circumnuclear disk. Possible explanations for the observed molecular gas distribution and kinematics are that a rotating gas disk disturbed by the jet, gas streaming toward the nucleus, or a ring with another smaller counter- or Keplarian-rotating gas disk inside.
Astronomy and Astrophysics
- Pub Date:
- June 2007
- galaxies: individual: <ASTROBJ>M 51</ASTROBJ>;
- galaxies: individual: <ASTROBJ>NGC 5194</ASTROBJ>;
- galaxies: ISM;
- galaxies: Seyfert;
- 5 pages, 4 figures, to appear in A&