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arXiv · 1607.04040

Enhanced Star Formation of Less Massive Galaxies in a Proto-Cluster at z=2.5

Masao Hayashi·Tadayuki Kodama·Ichi Tanaka·Rhythm Shimakawa·Yusei Koyama·Ken-ichi Tadaki·Tomoko L. Suzuki·Moegi Yamamoto
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Abstract

We investigate a correlation between star-formation rate (SFR) and stellar mass for Halpha emission line galaxies (HAEs) in one of the richest proto-clusters ever known at z~2.5, USS 1558-003 proto-cluster. This study is based on a 9.7-hour narrow-band imaging data with MOIRCS on the Subaru telescope. We are able to construct a sample, in combination with additional H-band data taken with WFC3 on Hubble Space Telescope (HST), of 100 HAEs reaching the dust-corrected SFRs down to 3 Msun/yr and the stellar masses down to $10^{8.0}$ Msun. We find that while the star-forming galaxies with >$10^{9.3}$ Msun are located on the universal SFR-mass main sequence irrespective of the environment, less massive star-forming galaxies with <$10^{9.3}$ Msun show a significant upward scatter from the main sequence in this proto-cluster. This suggests that some less massive galaxies are in a starburst phase, although we do not know yet if this is due to environmental effects.

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Masao Hayashi, Tadayuki Kodama, Ichi Tanaka, Rhythm Shimakawa, Yusei Koyama, Ken-ichi Tadaki, Tomoko L. Suzuki, Moegi Yamamoto. 2016-07-14. Enhanced Star Formation of Less Massive Galaxies in a Proto-Cluster at z=2.5. https://doi.org/10.3847/2041-8205/826/2/l28

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