239.01 - Stacking the Cosmic Web in Lyman α Emission with MUSE & EAGLE

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Jan 8th at 2:00 PM until 2:10 PM

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Author(s): S. Gallego Gallego, S. Cantalupo, S. Lilly, ETH Zürich, Zürich, SWITZERLAND|
Institution(s): 1. ETH Zürich, Zürich, Switzerland.
Contributing team(s): MUSE Collaboration
Cosmological simulations suggest that most of the matter in the Universe is distributed along filaments connecting galaxies. Illuminated by the cosmic UV background (UVB), these structures are expected to glow in fluorescent Ly α emission with a surface brightness (SB) that is well below current limits for individual detections. We perform a stacking analysis of the deepest MUSE/VLT data using three-dimensional regions (subcubes) with orientations determined by the position of neighboring Ly α galaxies at 3 We construct mock cubes from the EAGLE simulations in order to constrain the Ly α signal from the Cosmic Web and the filament-galaxy connectivity. We found a strong correlation between the neighboring galaxy distance and the filament detection, and a small correlation with galaxy magnitudes and halo mass. Using our MUSE stacking results in combination with EAGLE constraints, we estimate a covering fraction of LLSs of about 10%, implying a photoionization rate below 2 x 1e-12 s^-1 at z~3.5.