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arXiv · astro-ph/9712135

Faint Infrared-Excess Field Galaxies: FROGs

Abstract

Deep near-infrared and optical imaging surveys in the field reveal a curious population of galaxies that are infrared-bright (I-K>4), yet with relatively blue optical colors (V-I<2). Their surface density, several per square arcminute at K>20, is high enough that if placed at z>1 as our models suggest, their space densities are about one-tenth of phi-*. The colors of these ``faint red outlier galaxies'' (fROGs) may derive from exceedingly old underlying stellar populations, a dust-embedded starburst or AGN, or a combination thereof. Determining the nature of these fROGs, and their relation with the I-K>6 ``extremely red objects,'' has implications for our understanding of the processes that give rise to infrared-excess galaxies in general. We report on an ongoing study of several targets with HST & Keck imaging and Keck/LRIS multislit spectroscopy.

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BibTeXRIS

L. A. Moustakas, M. Davis, S. E. Zepf, A. J. Bunker. 1997-12-10. Faint Infrared-Excess Field Galaxies: FROGs. https://arxiv.org/abs/astro-ph/9712135

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