ケック宇宙ウェブ・イメージャー、銀河をつなぐフィラメント状ネットワークをこれまでで最もよく見せてくれる Keck Cosmic Web Imager offers best glimpse yet of the filamentous network that connects galaxies
2023-09-28 カリフォルニア工科大学(Caltech)
◆これらのガスの流れは、宇宙の構造である「宇宙のウェブ」の一部で、これまで観測が難しかったが、カリフォルニア工科大学のKCWI装置によって初めて直接観測されました。この観測は、銀河がガスフィラメントから燃料を供給され、新しい星を生み出す「冷流モデル」を支持するもので、銀河形成や暗黒物質の分布を理解するための重要な情報を提供します。
＜関連情報＞
- https://www.caltech.edu/about/news/cosmic-web-lights-up-in-the-darkness-of-space
- https://www.nature.com/articles/s41550-023-02054-1
宇宙構造と相関するライマンαの大拡散発光 Extensive diffuse Lyman-α emission correlated with cosmic structure
D. Christopher Martin,Behnam Darvish,Zeren Lin,Renyue Cen,Mateusz Matuszewski,Patrick Morrissey,James D. Neill & Anna M. Moore
Nature Astronomy Published:28 September 2023
DOI:https://doi.org/10.1038/s41550-023-02054-1
Abstract
The intergalactic medium represents the dominant reservoir of baryons at high redshift, traces the architecture of the cosmic web dominated by dark matter and fuels ongoing galaxy evolution. The intergalactic medium has been studied using the absorption lines of quasi-stellar objects, including the Lyman-α forest, but these absorption lines are unable to provide the information that emission maps would give. However, because of the low surface brightness and extended, diffuse distribution, direct detection of an emission equivalent to the absorption Lyman-α forest has not been possible with existing instrumentation and observational approaches. Using a purpose-built instrument, with nod-and-shuffle and dual-field subtraction, we have detected an emission Lyman-α forest. The emission forest is highly extended, shows filamentary morphology with filaments connecting galaxies, exhibits statistics like the absorption Lyman-α forest, displays spectra resembling the absorption forest and is correlated with galaxy-traced overdensities consistent with bias like dark matter. We conclude that the emission Lyman-α forest may provide a new tool for tracing a substantial fraction of the cosmic web of baryons and dark matter.
