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Infrared images of merging galaxiesInfrared imaging of interacting galaxies is especially interesting because their optical appearance is often so chaotic due to extinction by dust and emission from star formation regions, that it is impossible to locate the nuclei or determine the true stellar distribution. However, at near-infrared wavelengths extinction is considerably reduced, and most of the flux from galaxies originates from red giant stars that comprise the dominant stellar component by mass. Thus near infrared images offer the opportunity to study directly components of galactic structure which are otherwise inaccessible. Such images may ultimately provide the framework in which to understand the activity taking place in many of the mergers with high Infrared Astronomy Satellite (IRAS) luminosities. Infrared images have been useful in identifying double structures in the nuclei of interacting galaxies which have not even been hinted at by optical observations. A striking example of this is given by the K images of Arp 220. Graham et al. (1990) have used high resolution imaging to show that it has a double nucleus coincident with the radio sources in the middle of the dust lane. The results suggest that caution should be applied in the identification of optical bright spots as multiple nuclei in the absence of other evidence. They also illustrate the advantages of using infrared imaging to study the underlying structure in merging galaxies. The authors have begun a program to take near infrared images of galaxies which are believed to be mergers of disk galaxies because they have tidal tails and filaments. In many of these the merger is thought to have induced exceptionally luminous infrared emission (cf. Joseph and Wright 1985, Sanders et al. 1988). Although the optical images of the galaxies show spectacular dust lanes and filaments, the K images all have a very smooth distribution of light with an apparently single nucleus.
Document ID
19910007591
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Wright, G. S.
(Joint Astronomy Centre Hilo, HI., United States)
James, P. A.
(Hawaii Univ. Honolulu., United States)
Joseph, R. D.
(Hawaii Univ. Honolulu., United States)
Mclean, I. S.
(California Univ. Los Angeles., United States)
Doyon, R.
(Imperial Coll. of Science and Technology London, United Kingdom)
Date Acquired
September 6, 2013
Publication Date
November 1, 1990
Publication Information
Publication: NASA, Marshall Space Flight Center, Paired and Interacting Galaxies: International Astronomical Union Colloquium No. 124
Subject Category
Astrophysics
Accession Number
91N16904
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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