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Double-barred starburst galaxies viewed by ISOCAM

H. Wozniak 1, D. Friedlik 2, L. Martinetk 2, & D. Pfennigerk 2

1 IRAP/Observatoire de Marseille, 2, Place Le Verrier, F-13248 Marseille cedex 4
2 Geneva Observatory, Switzerland

Double-barred galaxies has gained strong new interests from the point of view of observations (e.g. Wozniak et al. 1995; Friedli et al. 1996), numerical simulations (e.g Friedli & Martinet 1993; Friedli 1996) and theory (e.g. Shlosman et al. 1989). Indeed, double-barred galaxies or galaxies with central non-axisymmetric deformations are very common, especially in early-type disk galaxies. Moreover, bars within bars systems might play a crucial role in fueling central activity of galaxies and shaping circumnuclear starbursts.

The present study is part of a global project intended to clarify the interplay between central starburst activity and the non-axisymmetric dynamics of barred galaxies. Our general approach makes use of multiwavelength observations coupled with self-consistent numerical simulations. ISOCAM observations in LW2 and LW3 bands offer us exploring the characteristics of the radiation coming from ``unidentified infrared emission bands'' and hot dust. An extended comparison with the radiation at optical, near-infrared and millimeter wavelengths allows to describe the typical characteristics (SFR, age, stellar populations, etc.) of the circumnuclear star forming regions.

In this talk, a special emphasis is given on the fresh 6.75 and 15$\mu$m data that have been obtained with ISOCAM on board of ISO for two galaxies, namely:

We compare NGC 1097 to NGC 4321. Recent results from numerical simulations bring new clues to understand the major and striking differences between the MIR emission from NGC 1097 and NGC 4321.


next up previous contents index
Next: Poster session F Cosmology Up: Poster session E Galaxies Previous: The physical structure of
"The Universe as seen by ISO", 20 - 23 October 1998, Paris: Abstract Book