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arXiv · 1704.05979

The nature of H$α$-selected galaxies along the large-scale structure at z=0.4 revealed by Subaru Hyper Suprime-Cam survey

Yusei Koyama·Masao Hayashi·Masayuki Tanaka·Tadayuki Kodama·Rhythm Shimakawa·Moegi Yamamoto·Fumiaki Nakata·Ichi Tanaka·Tomoko Suzuki·Ken-ichi Tadaki·Atsushi J. Nishizawa·Kiyoto Yabe·Yoshiki Toba·Lihwai Lin·Hung-Yu Jian·Yutaka Komiyama
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Abstract

We present the environmental dependence of colour, stellar mass, and star formation (SF) activity in H-alpha-selected galaxies along the large-scale structure at z=0.4 hosting twin clusters in DEEP2-3 field, discovered by Subaru Strategic Programme of Hyper Suprime-Cam (HSC SSP). By combining photo-z selected galaxies and H-alpha emitters selected with broad-band and narrow-band (NB) data of the recent data release of HSC SSP (DR1), we confirm that galaxies in higher-density environments or galaxies in the cluster central regions show redder colours. We find that there still remains a possible colour-density and colour-radius correlation even if we restrict the sample to H-alpha-selected galaxies, likely due to the presence of massive H-alpha emitters in denser regions. We also find a hint of increased star formation rates (SFR) amongst H-alpha emitters towards the highest-density environment, again primarily driven by the excess of red/massive H-alpha emitters in high-density environment, while their specific SFR does not significantly change with environment. This work demonstrates the power of the HSC SSP NB data to study SF galaxies across environment in the distant universe.

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Yusei Koyama, Masao Hayashi, Masayuki Tanaka, Tadayuki Kodama, Rhythm Shimakawa, Moegi Yamamoto, Fumiaki Nakata, Ichi Tanaka, Tomoko Suzuki, Ken-ichi Tadaki, Atsushi J. Nishizawa, Kiyoto Yabe, Yoshiki Toba, Lihwai Lin, Hung-Yu Jian, Yutaka Komiyama. 2017-07-28. The nature of H$α$-selected galaxies along the large-scale structure at z=0.4 revealed by Subaru Hyper Suprime-Cam survey. https://doi.org/10.1093/pasj%2Fpsx078

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