Poster Presentation
First detections of Sill* halos at z=2-4 with MUSE
Presenter: Haruka Kusakabe (NAOJ)
The hydrogen of the circumgalactic medium (CGM) is found to be common among star-forming galaxies through extended Lya emission (Lya halos, e.g., Steidel+11; Leclercq+17; Kusakabe+22). The CGM is supposed to be metal enriched even at z > 2 from absorption line studies (e.g., Lehner+16; Muzahid+21; Davies+22). However, this method does not provide the spatial distribution of the CGM around individual galaxies. Recently the metal-enriched CGM has been mapped with [OII], MgII, and FeII* emission at z = 0-1.5 (e.g., Yuma+13; Finley+17; Leclercq+22) as well as with [CII] at z > 4 for massive galaxies (e.g., Fujimoto+19). At z =2-4, there is no bright emission tracer of the CGM, and the most promising but extremely faint tracer would be SiII*. In this project, we search for SiII* extended emission around 39 individual galaxies at z=2-4 using deep MUSE data (Bacon+23) and find 5 detections of SiII* halos. We also stack a subsample of UV-bright galaxies and confirm the presence of SiII* haloes. We investigate the surface brightness profiles of SiII* and discuss the origin of SiII* emission. We also compare observed surface brightness profiles and those in simulations in Mauerhofer+21.
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