read more
Home arrow Document
   
Subscriber Authentication Point
 
   
Free access article

Issue A&A
Volume 423, Number 2, August IV 2004
Page(s) 481 - 493
Section Extragalactic astronomy
DOI 10.1051/0004-6361:20034336



A&A 423, 481-493 (2004)
DOI: 10.1051/0004-6361:20034336

The nuclear ring in the unbarred galaxy NGC 278: Result of a minor merger?

J. H. Knapen1, L. F. Whyte2, W. J. G. de Blok3 and J. M. van der Hulst4

1  Centre for Astrophysics Research, University of Hertfordshire, Hatfield, Herts AL10 9AB, UK
    e-mail: j.knapen@star.herts.ac.uk
2  University of Nottingham, School of Physics and Astronomy, University Park, Nottingham, NG7 2RD, UK
3  Department of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff CF24 3YB, UK
4  Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen, The Netherlands

(Received 17 September 2003 / Accepted 24 April 2004 )

Abstract
We present fully sampled high angular resolution two-dimensional kinematics in the H $\alpha$ spectral line, optical and near-infrared imaging, as well as 21 cm atomic hydrogen data of the spiral galaxy NGC 278. This is a small non-barred galaxy, which has a bright star forming inner region of about 2 kpc in diameter, reminiscent of nuclear rings seen mainly in barred galaxies. The H $\alpha$ kinematics show a disturbed velocity field, which may be partly the result of spiral density wave streaming motions. The 21 cm data trace the atomic hydrogen well outside the optical disk. The $\ion$ is not abundant but clearly shows disturbed morphology and kinematics. We postulate that the current structure of NGC 278 is a result of a recent interaction with a small gas-rich galaxy, which is now dispersed into the outer disk of NGC 278. Non-axisymmetries set up in the disk by this minor merger may well be the cause of the intense star formation in the inner region, which can be interpreted as a rare example of a nuclear ring in a non-barred galaxy. Rather than being induced by a bar, this nuclear ring would then be the direct result of an interaction event in the recent history of the galaxy.


Key words: galaxies: individual: NGC 278 -- galaxies: ISM -- galaxies: kinematics and dynamics -- galaxies: spiral -- galaxies: structure

SIMBAD Objects



© ESO 2004


What is OpenURL?