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C. J. Lonsdale (Caltech)
The most luminous galaxies known are dominated by their infrared and submillimeter emission and they are far more numerous at early epochs than in the present day. Moreover they dominate the cosmic infrared extragalactic background, which roughly equals the total luminous energy output of galaxies at all other wavelengths combined. Are these enigmatic objects signposts to the formation of the most massive galaxies as the most massive haloes began to collapse? I will describe the power of Spitzer, and in particular the Spitzer Wide-area InfraRed Extragalactic Survey (SWIRE), to assess the nature of this population and its role in the development of galaxies as we see them today, and I will outline the important contributions we expect from future large IR and submm surveys. I will also examine the relationship of this population to high redshift massive galaxies detected by other means, highlighting a multiwavelength approach.
I will then consider how IR-luminous galaxies fare in current \LambdaCDM galaxy formation models, and I will highlight critical areas where observations and theory can jointly focus to address the most outstanding questions in our understanding of the formation of structures in the Universe. Key to fitting the pieces of the puzzle together is to map in space and time the distributions of galaxies of all kinds - passively evolving spheroids; quiescently star-forming systems; starbursts; AGN - within the dark matter density field, and in particular as a function of dark matter halo mass. I will highlight Spitzer surveys which are undertaking such studies from an infrared perspective, and will emphasize the importance of sensitive matching surveys across the electromagnetic spectrum to provide us with a complete picture of galaxy and structure formation, from galaxy cluster scales to >100Mpc scales.
This work is supported by NASA under the Spitzer Legacy Science Program.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.