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Two formation paths for cluster dwarf galaxies?

Bianca M. Poggianti·Nobunari Kashikawa·Terry Bridges·Bahram Mobasher·Yutaka Komiyama·Dave Carter·Sadanori Okamura·Masafumi Yagi
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Abstract

A surprising result of our recent spectroscopic survey of galaxies in the Coma cluster has been the discovery of a possible bimodal distribution in the metallicities of faint galaxies at $M_B>-17$. We identified a group of dwarfs with luminosity-weighted metallicities around solar and a group with [M/H] around -1.5. A metallicity bimodality among galaxies of similar luminosities is unexpected and suggests that faint cluster galaxies could be an heterogeneous population that formed through more than one evolutionary path, possibly as a consequence of the cluster environment.

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Bianca M. Poggianti, Nobunari Kashikawa, Terry Bridges, Bahram Mobasher, Yutaka Komiyama, Dave Carter, Sadanori Okamura, Masafumi Yagi. 2003-10-15. Two formation paths for cluster dwarf galaxies?. https://arxiv.org/abs/astro-ph/0310404

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