Astron. Astrophys. Suppl. Ser. 144, 85-121

The influence of interactions and minor mergers on the structure of galactic disks

I. Observations and disk models

U. Schwarzkopf^1,2 - R.-J. Dettmar ¹

Send offprint request: U. Schwarzkopf,
e-mail: schwarz@as.arizona.edu

1 - Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
2 - Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, Arizona 85721, U.S.A.

Received July 22, 1999; accepted March 6, 2000

Abstract:

This paper is the first part in our series on the influence of tidal interactions and minor mergers on the radial and vertical disk structure of spiral galaxies. We report on the sample selection, our observations, and data reduction. Surface photometry of the optical and near infrared data of a sample of 110 highly-inclined/edge-on disk galaxies are presented. This sample consists of two subsamples of 61 non-interacting galaxies (control sample) and of 49 interacting galaxies/minor merging candidates. Additionally, 41 of these galaxies were observed in the near infrared. We show that the distribution of morphological types of both subsamples is almost indistinguishable, covering the range between $0 \le T \le 9$. An improved, 3-dimensional disk modelling- and fitting procedure is described in order to analyze and to compare the disk structure of our sample galaxies by using characteristic parameters. We find that the vertical brightness profiles of galactic disks respond very sensitive even to small deviations from the perfect edge-on orientation. Hence, projection effects of slightly inclined disks may cause substantial changes in the value of the disk scale height and must therefore be considered in the subsequent study.

Key words: galaxies: general, interactions, photometry, spiral, statistics -- infrared: galaxies