NGC 5953/54: BVRIHαJK photometry and [N II] Fabry-Perot interferometry. I. The data

Abstract

We present new BVRIHαJK 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 μ ɛ = 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 (>=1.5 kpc) in all the observed bands and traces of faint external fan-like features in Hα and [N II]. A compact flocculent spiral pattern (<=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.

Based on data obtained at the 1.5-m and 2.1-m telescopes of the Observatorio Astronomico Nacional, San Pedro Mártir, Baja California, México, operated by the Instituto de Astronomía, UNAM.

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