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A 100 kpc Galactic Wind Feeding the Circumgalactic Medium

Alison Coil

UC San Diego

The origin of the metal-enriched and massive circumgalactic medium (CGM) remains elusive. Theory points to expulsion from galaxies through outflowing winds as a dominant mechanism, but no directly-imaged winds reach far into the physical scale of the CGM. Using KCWI on Keck, we have discovered an enormous (100 kpc x 80 kpc) ionized gas outflow directly connecting the galactic wind from a massive, compact starburst galaxy at z~0.5 to its surrounding CGM. This wind is depositing metal-enriched gas to over 20 times the stellar radius of the galaxy through an hourglass-shaped nebula; the outflow is the largest galactic wind ever observed. Multiple gas phases (ionized, neutral, and molecular) are observed extending to 20 kpc moving at extremely high speeds up to ~1500 km/s. This outflow may be feeding the CGM both by depositing gas directly and by entraining and cooling hot halo gas. I will further discuss the galaxy sample that this wind was discovered within and on-going work to characterize the properties of both the host galaxies and their outflows.

Date: Thursday, 17 February 2022
Time: 11:30
Where: Université de Montréal

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