Oral Presentation

[Remote] Ruby-Rush; Investigating accelerated growth of massive galaxies at z~5

Author(s): Kosuke Takahashi, Tadayuki Kodama, Kazuki Daikuhara, Riho Okazaki(Tohoku Univ.), Jun Toshikawa(Univ. of Hyogo), Ken-ichi Tadaki(Hokkai Gakuen Univ.), Yusei Koyama, Kentaro Motohara(NAOJ), Masahiro Konishi(Univ. of Tokyo), and Ruby-Rush team members.

Presenter: Kosuke Takahashi (Tohoku University)

Identifying when/where massive galaxies first appeared in the Universe and knowing how the star-forming activities of those galaxies were quenched is critical for understanding galaxy formation and early evolution. It can also put strong constraints on the efficiency of galaxy formation in the early Universe and, eventually, on the current standard theory of hierarchical structure formation. Recent observations have confirmed the existence of the massive galaxies (~10^11Msun) at z~4.6. In this study, we aim to go further back in time and search for protoclusters at z~5 to discover mature, massive galaxies of comparable mass that have already quenched star-forming activities. We will report our discoveries of strong candidates of massive galaxies at z~5 and discuss the accelerated massive galaxy formation in the high-density regions only a billion years after the Big Bang.