Work

Link between the properties of circumgalactic outflows and the recent star formation history of their host galaxies

Year: 2026

Type: article

Abstract: Galactic outflows play a key role in galaxy evolution, yet their connection to the star formation history (SFH) of their host galaxies remains poorly constrained. Building on previous work modeling the extended emission of galaxies observed with VLT/MUSE to infer outflow properties, we investigate how these properties depend on the recent SFH. We derive non-parametric SFHs by fitting spectroscopic and photometric data with linear combinations of single stellar population models, and compute star formation rates (SFRs) over different timescales sensitive to recent stochastic bursts. We find moderate correlations between these SFRs (and sSFRs) and the kinematic properties of the outflows, namely their maximum velocity and radial acceleration rate. Such correlations are not recovered using SFR tracers based on Mg II O II luminosity or parametric SFHs, highlighting the importance of capturing bursty star formation in timescales consistent with the traveling time of ejected gas into the circumgalactic medium. Using the extent and kinematics of the halos, we further estimate the outflow launching time for each galaxy and compute a corresponding SFR averaged over the relevant timescale. We identify a correlation between this SFR and the maximum outflow velocity, although it is not significantly stronger than the correlations obtained using fixed averaging timescales. This suggests that the properties of halos are shaped by a series of star formation events rather than by a single dominant burst. Lastly, we find faster outflows in galaxies whose recent star formation is dominated by one or a few concentrated episodes, whereas galaxies with star formation spread more evenly over time exhibit slower outflows. These results indicate that the circumgalactic medium acts as a dynamical archive of recent star formation, linking bursty galaxy growth to outflow kinematics and providing a direct observational constraint on feedback models. Mg II Mg II

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202662252