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Searching for cosmic missing baryons with DIOS -- Diffuse Intergalactic Oxygen Surveyor --

Yasushi Suto·Kohji Yoshikawa·Noriko Y. Yamasaki·Kazuhisa Mitsuda·Ryuichi Fujimoto·Tae Furusho·Takaya Ohashi·Manabu Ishida·Shin Sasaki·Yoshitaka Ishisaki·Yuzuru Tawara·Akihiro Furuzawa
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Abstract

Approximately 30 to 50 percent of the total baryons in the present universe is supposed to take a form of warm/hot intergalactic medium (WHIM) whose X-ray continuum emission is very weak. In order to carry out a direct and homogeneous survey of elusive cosmic missing baryons, we propose a dedicated soft-X-ray mission, {\it DIOS} (Diffuse Intergalactic Oxygen Surveyor). The unprecedented energy resolution ($\sim 2$eV) of the XSA (X-ray Spectrometer Array) on-board {\it DIOS} enables us to identify WHIM with gas temperature $T=10^{6-7}$K and overdensity $δ=10-100$ located at $z<0.3$ through emission lines of O{\sc vii} and O{\sc viii}. {\it DIOS}, hopefully launched in several years, promises to open a new window of detection and characterization of cosmic missing baryons, and to provide yet another important and complementary tool to trace the large-scale structure of the universe.

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Yasushi Suto, Kohji Yoshikawa, Noriko Y. Yamasaki, Kazuhisa Mitsuda, Ryuichi Fujimoto, Tae Furusho, Takaya Ohashi, Manabu Ishida, Shin Sasaki, Yoshitaka Ishisaki, Yuzuru Tawara, Akihiro Furuzawa. 2004-02-17. Searching for cosmic missing baryons with DIOS -- Diffuse Intergalactic Oxygen Surveyor --. https://arxiv.org/abs/astro-ph/0402389

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