EDP Sciences
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Volume 412, Number 3, December IV 2003
Page(s) 669 - 687
Section Galactic structure and dynamics
DOI http://dx.doi.org/10.1051/0004-6361:20031445

A&A 412, 669-687 (2003)
DOI: 10.1051/0004-6361:20031445

NGC 5953/54: BVRIH$\alpha$JK photometry and [N II] Fabry-Perot interferometry

I. The data
H. M. Hernández-Toledo, I. Fuentes-Carrera, M. Rosado, I. Cruz-González, A. Franco-Balderas and D. Dultzin-Hacyan

Instituto de Astronomía - UNAM - Apartado Postal 70-264, 04510 México D.F., México
    e-mail: [margarit;irene;iqui;alfred;deborah]@astroscu.unam.mx
(Received 14 April 2003 / Accepted 15 September 2003 )

We present new BVRIH $\alpha$JK imaging and [N II] scanning Fabry-Perot observations for the interacting galaxy pair NGC 5953/54. Morphology is reviewed using a combination of contrast-enhanced images, color-index maps, and geometric (radial  $\mu$, $\epsilon = 1 - b/a$, PA and  a4/a) profile parameters. Our data are complemented by archived V/ R/ H images from HST. The Seyfert 2 NGC 5953 shows an underlying featureless disk ( $\geq$ 1.5 kpc) in all the observed bands and traces of faint external fan-like features in H $\alpha$ and [N II]. A compact flocculent spiral pattern ( $\leq$ 1.5 kpc), and a ~ 60 pc bar-like central structure are also observed. The Liner galaxy NGC 5954 is an inclined and distorted spiral with a strong circumnuclear starburst region and star-forming regions throughout the disk. A tidal bridge or distorted arm appears to link the two galaxies, extending to the northwest as a linear feature (plume). NGC 5954 also shows blue filaments delineating bubble-like features on the north side of the nucleus where our Fabry-Perot observations reveal double emission line profiles. We derive BVRIJK magnitudes and surface brightness profiles for the galaxies. HST  V/ R and H-band surface brightness profiles are also presented for NGC 5953. Fabry-Perot observations yield an [N II] velocity field and rotation curves for the components. The observations coupled with results from a simulation atlas of tidal features allow us 1) to suggest a tentative geometry of the encounter in NGC 5953/54, and 2) to comment about a suspected secular transformation in NGC 5953/54 via the interaction process. A forthcoming paper is devoted to a more detailed analysis of our observations including HI synthesis observations and n-body numerical simulations.

Key words: galaxies: spiral -- galaxies: structure -- galaxies: photometry -- galaxies: interactions -- galaxies: fundamental parameters -- galaxies: kinematics and dynamics

Offprint request: H. M. Hernández-Toledo, hector@astroscu.unam.mx

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© ESO 2003