Two-Component Spectral Emission Lines in NGC 3227 (Poster paper)

Summary

ABSTRACT

We have obtained bi-dimensional spectroscopy of intermediate spectral resolution of the circumnuclear region of NGC 3227. We found two-peaked emission line profiles which evidence the presence of different kinematical components. The classification of the line profiles after attempting their two-components Gaussian fitting is discussed.

INTRODUCTION

The presence of asymmetries in the profiles of the narrow emission lines (NEL) of Seyfert nuclei is a common result (see e.g. Veilleux 1991). In NGC 3227 the asymmetrical profiles of the NEL corresponding to the optical nucleus suggest the existence of a substructure. Observing with intermediate spectral resolution an extended region in the environment of the nucleus of this galaxy, we obtained profiles showing at least two components. We present here this result whose importance for kinematics is obvious.

Our instrumental set-up is based on an optical fiber bundle of 95 fibers disposed in an hexagonal lattice, covering a projected rectangle of 9 arcsec × 12 arcsec. The spatial sampling was ∼ 1 arcsec, and the spectral resolution 2Å. The spectral range covered was (4600–5400Å) which includes the Hβ and [0 III]λλ4959,5007 lines. We used this fiber bundle in combination with the ISIS spectrograph and the 4.2m WHT sited on the island of La Palma. The data were acquired on December 10, 1992. For details about bi-dimensional spectroscopy with optical fibers see Arribas, Mediavilla, and Rasilla (1991), Vanderriest (1993), or Shapovalova (these proceedings).