GREX-PLUS (Galaxy Reionization EXplorer and PLanetary Universe Spectrometer) is a mission candidate for a JAXA strategic L-class mission to be launched in the 2030s. Its primary science goals are two-fold: galaxy formation and evolution, and planetary system formation and evolution.
The GREX-PLUS spacecraft will carry a telescope with a 1 m primary mirror aperture cooled down to 50 K. The two science instruments will be onboard: a wide-field camera in the 2–8 μm wavelength band and a high-resolution spectrometer with a wavelength resolution of 30,000 in the 10–18 μm band. The GREX-PLUS wide-field camera aims to detect the first generation of galaxies at redshift z>15.
The GREX-PLUS high-resolution spectrometer aims to identify the location of the water “snowline” in protoplanetary disks. Both instruments will provide unique datasets for a broad range of scientific topics, including galaxy mass assembly, the origin of supermassive blackholes, infrared background radiation, molecular spectroscopy in the interstellar medium, transit spectroscopy of exoplanet atmospheres, planetary atmospheres in the Solar System, and so on.
This document is the second version of a collection of scientific themes that can be achieved with GREX-PLUS. Each section in Chapters~2 and 3 is based on presentations at several GREX-PLUS Science Workshops.
GREX-PLUS Science Team: Shunsuke Baba (ISAS/JAXA), Sirio Belli (Universita di Bologna), Pietro Benotto (INAF – Osservatorio Astronomico di Padova / Universita di Bologna), Ivan Delvecchio (INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna), Yoshinobu Fudamoto (Chiba University), Yuka Fujii (NAOJ), Yuichi Harikane (University of Tokyo), Yasuhiro Hirahara (Nagoya University), Akio K. Inoue (Waseda University), Yoshiyuki Inoue (University of Osaka), Hajime Kawahara (ISAS/JAXA / University of Tokyo), Taiki Kawamuro (University of Osaka), Yui Kawashima (Kyoto University), Lucas Kimmig (Ludwig-Maximilians-University / University of Nottingham), Tadayuki Kodama (Tohoku University), Mitsuru Kokubo (NAOJ), Hiroyuki Kurokawa (University of Tokyo), Katsunori Kusakabe (University of Osaka), Kosei Matsumoto (Ghent University), Noriyuki Matsunaga (University of Tokyo), Taro Matsuo (University of Osaka), Yoshiki Matsuoka (Ehime University), Shuji Matsuura (Kwansei Gakuin University), Toru Misawa (Shinshu University), Shota Miyazaki (ISAS/JAXA), Alessia Moretti (INAF – Osservatorio Astronomico di Padova), Kumiko Morihana (NAOJ), Takashi Moriya (NAOJ), Kentaro Nagamine (University of Osaka / University of Tokyo / University of Nevada Las Vegas), Kimihiko Nakajima (Kanazawa University), Hideko Nomura (NAOJ), Shota Notsu (University of Tokyo), Takafumi Ootsubo (University of Occupational and Environmental Health), Kazumasa Ohno (NAOJ), Giorgia Peluso (INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna), Bianca M. Poggianti (INAF – Osservatorio Astronomico di Padova), Mario Radovich (INAF – Osservatorio Astronomico di Padova), Giulia Rodighiero (University of Padova), Hideo Sagawa (Kyoto Sangyo University), Kazuhiro Shimasaku (University of Tokyo), Takashi Shimonishi (Niigata University), Ken-ichi Tadaki (Hokkai-Gakuen University), Kosuke Takahashi (Tohoku University), Michihiro Takami (ASIAA), Shuya Tan (JAMSTEC), Takumi Tanaka (University of Tokyo), Tsuyoshi Terai (NAOJ), Yoshiki Toba (Ritsumeikan University), Roberta Tripodi (INAF – Astronomical Observatory of Rome), Francesco Valentino (DAWN / Technical University of Denmark), Benedetta Vulcani (INAF – Osservatorio Astronomico di Padova), Taihei Yano (NAOJ), Chikako Yasui (NAOJ), Stefano Zibetti (INAF – Arcetri Astrophysical Observatory)
Comments: This is a major updated version from arXiv:2304.08104
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2606.05237 [astro-ph.IM](or arXiv:2606.05237v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2606.05237
Focus to learn more
Submission history
From: Akio Inoue
[v1] Wed, 3 Jun 2026 04:42:32 UTC (45,182 KB)
https://arxiv.org/abs/2606.0523
Astrobiology, Astronomy,
