EDP Sciences
Free access
Volume 377, Number 3, October III 2001
Page(s) 745 - 758
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20010991

A&A 377, 745-758 (2001)
DOI: 10.1051/0004-6361:20010991

The velocity field of UGC 6697 revisited

G. Gavazzi1, M. Marcelin2, A. Boselli2, P. Amram2, J. M. Vílchez3, J. Iglesias-Paramo2 and M. Tarenghi4

1  Università degli Studi di Milano -Bicocca, P.zza delle scienze 3, 20126 Milano, Italy
2  Laboratoire d'Astrophysique de Marseille, 2 place Le Verrier, 13248 Marseille Cedex 4, France
3  Instituto de Astrofísica de Andalucía, CSIC, Apdo. 3004, 18080, Granada, Spain
4  European Southern Observatory, K. Schwarzschild Str. 2, 857448, Garching bei Muenchen, Germany

(Received 21 December 2000 / Accepted 5 July 2001)

The edge-on galaxy UGC 6697 has a peculiar morphological appearance: a high surface brightness SE component and what appears to be a tidal tail with blue color and low surface brightness extending toward the NW, as dramatically evidenced in subarcsecond broad band images taken with the VLT and in a deep $\rm H_{\alpha}$ frame. Long-slit spectroscopy shows a 500 km s-1 rigid-body rotation curve with a sudden central velocity jump, of more than 200 km s-1 amplitude. Fabry-Perot observations of the $\rm H_{\alpha}$ emission line enable us to trace a detailed 2D velocity field, confirming the complex kinematical behaviour, particularly in the circumnuclear region where multiple velocity components are clearly superposed on the same line of sight. This region hosts a double nucleus and shows sudden color and metallicity gradients, which can be reconciled with the complex velocity field assuming the presence of a second galaxy hidden behind the main body of UGC 6697.

Key words: galaxies: individual: UGC 6697 -- galaxies: interactions -- kinematics and dynamics

Offprint request: G. Gavazzi, Giuseppe.Gavazzi@mib.infn.it

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© ESO 2001