A&A 408, 873-885 (2003)
DOI: 10.1051/0004-6361:20030951

Minor-axis velocity gradients in spirals and the case of inner polar disks

E. M. Corsini, A. Pizzella, L. Coccato and F. Bertola

Dipartimento di Astronomia, Università di Padova, vicolo dell'Osservatorio 2, 35122 Padova, Italy
(Received 4 March 2003 / Accepted 3 June 2003)

Abstract
We measured the ionized-gas and stellar kinematics along the major and minor axis of a sample of 10 early-type spirals. Much to our surprise we found a remarkable gas velocity gradient along the minor axis of 8 of them. According to the kinematic features observed in their ionized-gas velocity fields, we divide our sample galaxies in three classes of objects. (i) NGC 4984, NGC 7213, and NGC 7377 show an overall velocity curve along the minor axis without zero-velocity points, out to the last measured radius, which is interpreted as due to the warped structure of the gaseous disk. (ii) NGC 3885, NGC 4224, and NGC 4586 are characterized by a velocity gradient along both major and minor axis, although non-zero velocities along the minor axis are confined to the central regions. Such gas kinematics have been explained as being due to non-circular motions induced by a triaxial potential. (iii) NGC 2855 and NGC 7049 show a change of slope of the velocity gradient measured along the major axis (which is shallower in the center and steeper away from the nucleus), as well as non-zero gas velocities in the central regions of the minor axis. This has been attributed to the presence of a kinematically-decoupled gaseous component in orthogonal rotation with respect to the galaxy disk, namely an inner polar disk. The case and origin of inner polar disks are discussed and the list of their host galaxies is presented.

Key words: galaxies: kinematics and dynamics -- galaxies: spiral -- galaxies: structure

Offprint request: E. M. Corsini, corsini@pd.astro.it

SIMBAD Objects
Tables at the CDS

© ESO 2003

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

• If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
• You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
• You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.