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arXiv · astro-ph/9812476

Mid-Infrared Images of Luminous Infrared Galaxies in a Merging Sequence

Chorng-Yuan Hwang·K. Y. Lo·Yu Gao·Robert A. Gruendl·Nanyao Y. Lu
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Abstract

We report mid-infrared observations of several luminous infrared galaxies (LIGs) carried out with the Infrared Space Observatory. Our sample was chosen to represent different phases of a merger sequence of galaxy-galaxy interaction with special emphasis on early/intermediate stages of merging. The mid-infrared emission of these LIGs shows extended structures for the early and intermediate mergers, indicating that most of the mid-infrared luminosities are not from a central active galactic nucleus (AGN). Both the infrared hardness (indicated by the IRAS 12, 25, and 60 $\micron$ flux density ratios) and the peak-to-total flux density ratios of these LIGs increase as projected separation of these interacting galaxies become smaller, consistent with increasing star formation activities that are concentrated to a smaller area as the merging process advances. These observations provide among the first observational constraint of largely theoretically based scenarios.

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Chorng-Yuan Hwang, K. Y. Lo, Yu Gao, Robert A. Gruendl, Nanyao Y. Lu. 1998-12-30. Mid-Infrared Images of Luminous Infrared Galaxies in a Merging Sequence. https://doi.org/10.1086/311839

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