2024/09/16 by Serena Perrotta, Perrotta, Serena, Alison L. Coil +24 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2409.10013
openalex publication_date 2024/09/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
High-velocity outflows are ubiquitous in compact, massive (M_* ∼ 1011 M\odot), z ∼ 0.5 galaxies with extreme star formation surface densities (ΣSFR ∼ 2000 M\odot yr-1 kpc-2). We have previously detected and characterized these outflows using MgII absorption lines. To probe their full extent, we present Keck/KCWI integral field spectroscopy of the [OII] and MgII emission nebulae surrounding all of the 12 galaxies in this study. We find that [OII] is more effective than MgII in tracing low surface brightness, extended emission in these galaxies. The [OII] nebulae are spatially extended beyond the stars, with radial extent R90 between 10 and 40 kpc. The nebulae exhibit non-gravitational motions, indicating galactic outflows with maximum blueshifted velocities ranging from -335 to -1920 km s-1. The outflow kinematics correlate with the bursty star formation histories of these galaxies. Galaxies with the most recent bursts of star formation (within the last < 3 Myr) exhibit the highest central velocity dispersions (σ> 400 km s-1), while the oldest bursts have the lowest-velocity outflows. Many galaxies exhibit both high-velocity cores and more extended, slower-moving gas indicative of multiple outflow episodes. The slower, larger outflows occurred earlier and have decelerated as they propagate into the CGM and mix on timescales > 50 Myr.