We present Spitzer observations of Tidal Dwarf Galaxies (TDGs) in three interacting systems: NGC 5291, Arp105 and Stephan's Quintet. The spectra show bright emission from polyaromatic hydrocarbons (PAHs), nebular lines and warm molecular hydrogen, characteristic of recent episodes of star formation. The PAH emission that falls in the IRAC 8.0 micron band leads to the TDGs having an extremely red IRAC color, with [4.5] - [8.0] > 3. The emission from PAHs is characterized by a model with mainly neutral 100-C PAH atoms.
@article{arxiv.0709.1468,
title = {Spitzer Observations of Tidal Dwarf Galaxies},
author = {Sarah J. U. Higdon and James L. Higdon},
journal= {arXiv preprint arXiv:0709.1468},
year = {2009}
}
Comments
To be published in the proceedings of IAU Symposium 244: "Dark Galaxies and Lost Baryons", J. I. Davies & M. D. Disney. eds., Cambridge University Press. 2 pages