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Statistical properties of local and intermediate z galaxies

F. Hammer
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Abstract

Galaxy evolution during the last 9 Gyr is discussed. It can be traced back from well known present-day galaxies or directly observed for galaxies at different look back times. This requires clear and consistently matched selection criteria for galaxy samples. There is a net decrease of rest-frame, UV luminosity density, at least since z = 1. It is interpreted as an important decline of the star formation since the last ~9 Gyr. A similar trend is found for the evolution of the IR luminosity density which accounts for heavily extincted starbursts. Interestingly the global star formation density, after including IR selected galaxies, is twice the value of estimates based on the UV luminosity density, and this holds from z=0 to z=1. Large disks are not contributing much to the observed decrease, which is mainly related to significant changes with the epoch in the distribution of galaxy morphologies. A significant fraction of the global star formation occurs in luminous galaxies which are apparently small or in interacting galaxies detected in the deepest IR or radio surveys.

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F. Hammer. 1999-12-09. Statistical properties of local and intermediate z galaxies. https://arxiv.org/abs/astro-ph/9912196

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