PEGASUS (Pfs Emission-line GAlaxy SUrvey with Subaru): I. Three-dimensional large-scale structures at $z > 1$ probed with emission-line galaxies
Year: 2026
Type: preprint
Abstract: To comprehensively understand the environmental effects on galaxy evolution, it is crucial to precisely map the distribution and thoroughly examine the properties of galaxies, including low-mass building blocks. Deep narrow-band imaging observations conducted with Hyper Suprime-Cam (HSC) on the Subaru Telescope systematically probed the distribution of low-mass star-forming galaxies as H$α$, [O {\footnotesize II}], and [O {\footnotesize III}] emission-line galaxies at $0.4\leq z\leq1.6$. We perform a comprehensive spectroscopic follow-up observation of these emission-line galaxies with narrow-band-based emission-line fluxes $\geq 2\times10^{-17}$ erg s$^{-1}$ cm$^{-2}$ within $\approx1.8$ deg$^2$ area centered on the COSMOS field using `Ōnohi`ula - Prime Focus Spectrograph (PFS) on the Subaru Telescope. In this paper, we outline the data product and present the large-scale structures at $z>1$. 9079 out of 9917 of the targets are observed, and the redshifts of 92\%~of the observed targets are successfully confirmed. We survey groups, filamentary large-scale structures, and voids at $z=1.19$, $1.47$, and $1.60$ based on the three-dimensional distribution of $520-920$ [O {\footnotesize II}] emission-line galaxies with stellar masses $M_\star\geq10^{9.5}~M_{\odot}$ at each redshift. Groups with halo masses $1\times10^{12}-6\times10^{13}~M_{\odot}$ are identified along the filaments, whereas the most massive groups are located at the densest intersections of filaments as predicted by cosmological simulations. Voids hidden on the surface density maps are robustly extracted on the volume density map. Our spectroscopic sample provides a powerful basis for quantifying the evolution of galaxies along the diverse environments back in time toward cosmic noon epoch in forthcoming papers.
Source: arXiv (Cornell University)
Authors: Kubo, Mariko, Kodama, Tadayuki, Shimakawa, Rhythm, Koyama, Yusei, Onodera, Masato, Inoue, Akio K., Uchiyama, Hisakazu, Nagao, Tohru, Tadaki, Ken-ichi, Laishram, Ronaldo, Wagatsuma, Ryoma, Nuo, Chen, Kusakabe, Haruka, Kikuta, Satoshi, Sugahara, Yuma, Motohara, Kentaro, Daikuhara, Kazuki, Osato, Ken, Liang, Yongming
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, Princeton University, California Institute of Technology, Johns Hopkins University, Space Telescope Science Institute, European Space Agency, Queen's University Belfast, Durham University, Ministry of Education, Culture, Sports, Science and Technology, Academia Sinica, Cabinet Office, Government of Japan, Max-Planck-Gesellschaft, University of Tokyo, National Central University, Universidade de São Paulo, National Astronomical Observatory of Japan, High Energy Accelerator Research Organization, Eötvös Loránd Tudományegyetem, Max-Planck-Institut für Astrophysik, Max-Planck-Institut für Astronomie, Toray Science Foundation, Jet Propulsion Laboratory, Smithsonian Astrophysical Observatory, Science Mission Directorate, Japan Society for the Promotion of Science, Japan Science and Technology Agency, Planetary Science Division, Los Alamos National Laboratory
Awards: G1388641319, 宇宙の歴史の中間地点から俯瞰する大質量楕円銀河の形成史, Towards Ultimate Subaru: Galaxy formation history probed by deep near-infrared imaging with wide-field adaptive optics, Evolution of massive galaxies in the early Universe revealed through observations of massive galaxies searched by multi-wavelength wide and deep surveys, G4474636675, Unveiling the Diversity and Complete Census of Protoclusters through Multi-wavelength, Wide-field, High-resolution Observations with Ground- and Space-based Telescopes, G5627313610, G618131832, G6531013582, A NEO SEARCH PROGRAM USING THE PAN-STARRS PS1 TELESCOPETHE GOAL OF THE PROPOSED RESEARCH IS TO USE T, Galaxy Overdense Regions in the Distant Universe Revealed by Wide-Area Sky Survey and TAO, Comprehensive understanding of the formation history of structures in the Universe, G7187964967, Pan-STARRS1: Operations; Public Data Release; Education and Outreach, Subaru and TAO dual NB survey for gas accretion and star formation along large-scale structures at cosmic noon, Elucidating the Trigger and Feedback Mechanisms of the Most Concentrated Quasars at Cosmic Noon, G833430883, Multi-phase ionized-gas structures characteristic of early galaxies investigated by multi-wave integrated field spectroscopy
OpenAlex ID: W7214100630