EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 373/2 Article
Free access article

Issue A&A
Volume 373, Number 2, July II 2001
Page(s) 402 - 437
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20010548



A&A 373, 402-437 (2001)
DOI: 10.1051/0004-6361:20010548

Properties of tidally-triggered vertical disk perturbations

U. Schwarzkopf1, 2 and R.-J. Dettmar2

1  Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, Arizona 85721, USA
2  Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany

(Received 17 July 2000 / Accepted 9 April 2001 )

Abstract
We present a detailed analysis of the properties of warps and tidally-triggered perturbations perpendicular to the plane of 47 interacting/merging edge-on spiral galaxies. The derived parameters are compared with those obtained for a sample of 61 non-interacting edge-on spirals. The entire optical (R-band) sample used for this study was presented in two previous papers. We find that the scale height of disks in the interacting/merging sample is characterized by perturbations on both large ($\simeq$ disk cut-off radius) and short ($\simeq$ z0) scales, with amplitudes of the order of 280pc and 130pc on average, respectively. The size of these large (short) -scale instabilities corresponds to 14% (6% ) of the mean disk scale height. This is a factor of 2 (1.5) larger than the value found for non-interacting galaxies. A hallmark of nearly all tidally distorted disks is a scale height that increases systematically with radial distance. The frequent occurrence and the significantly larger size of these gradients indicate that disk asymmetries on large scales are a common and persistent phenomenon, while local disturbances and bending instabilities decline on shorter timescales. Nearly all (93% ) of the interacting/merging and 45% of the non-interacting galaxies studied are noticeably warped. Warps of interacting/merging galaxies are $\approx $2.5 times larger on average than those observed in the non-interacting sample, with sizes of the order of 340pc and 140pc, respectively. This indicates that tidal distortions do considerably contribute to the formation and size of warps. However, they cannot entirely explain the frequent occurrence of warped disks.


Key words: galaxies: evolution -- galaxies: general -- galaxies: interactions -- galaxies: spiral -- galaxies: structure -- galaxies: statistics

Offprint request: U. Schwarzkopf, schwarz@as.arizona.edu

SIMBAD Objects



© ESO 2001


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.