Formation of star clusters and enrichment by massive stars in simulations of low-metallicity galaxies with a fully sampled initial stellar mass function
Journal
Monthly Notices of the Royal Astronomical Society
Journal Volume
522
Journal Issue
2
Start Page
3092
End Page
3116
ISSN
0035-8711
1365-2966
Date Issued
2023-04-18
Author(s)
Natalia Lahén
Thorsten Naab
Guinevere Kauffmann
Dorottya Szécsi
Jessica May Hislop
Antti Rantala
Alexandra Kozyreva
Stefanie Walch
Abstract
We present new GRIFFIN project hydrodynamical simulations that model the formation of galactic star cluster populations in low-metallicity (Z = 0.00021) dwarf galaxies, including radiation, supernova, and stellar wind feedback of individual massive stars. In the simulations, stars are sampled from the stellar initial mass function (IMF) down to the hydrogen-burning limit of 0.08 M☉. Mass conservation is enforced within a radius of 1 pc for the formation of massive stars. We find that massive stars are preferentially found in star clusters and follow a correlation set at birth between the highest initial stellar mass and the star cluster mass that differs from pure stochastic IMF sampling. With a fully sampled IMF, star clusters lose mass in the galactic tidal field according to mass-loss rates observed in nearby galaxies. Of the released stellar feedback, 60 per cent of the supernova material and up to 35 per cent of the wind material reside either in the hot interstellar medium (ISM) or in gaseous, metal-enriched outflows. While stellar winds (instantaneously) and supernovae (delayed) start enriching the ISM right after the first massive stars form, the formation of supernova-enriched stars and star clusters is significantly delayed (by >50 Myr) compared to the formation of stars and star clusters enriched by stellar winds. Overall, supernova ejecta dominate the enrichment by mass, while the number of enriched stars is determined by continuous stellar winds. These results present a concept for the formation of chemically distinct populations of stars in bound star clusters, reminiscent of multiple populations in globular clusters.
Subjects
galaxies: dwarf
galaxies: star clusters: general
galaxies: star formation
methods: numerical
radiative transfer
stars: massive
SDGs
Publisher
Oxford University Press (OUP)
Type
journal article