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Paper: Mid-IR Imaging of Toomre's Merger Sequence
Volume: 197, XVth IAP Meeting Dynamics of Galaxies: From the Early Universe to the Present
Page: 335
Authors: Charmandaris, V.; Laurent, O.; Mirabel, I. F.; Gallais, P.
Abstract: We present results on mid-IR (5--16 microns) spectral imaging of a sequence of interacting galaxies, observed by ISOCAM. The galaxies are part of the well known Toomre's ``merger sequence'' which was defined as a sample of galaxies depicting progressive snapshots in the time evolution of a merging event. To trace the intensity of the radiation field in a starburst, we use the ratio of the 15 microns to 7 microns flux. Our analysis indicates that this ratio increases as galaxies move from the pre-starburst to the starburst phase and goes again down to ~ 1 in the post-starburst phase, a value typical of normal star forming regions in galactic disks. Moreover, we find that the variation of this ratio is well correlated with the one of the IRAS 25 microns/12 microns and 60 microns/100 microns flux ratios.
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