Speaker
Description
Recent observations of the Sunburst Arc galaxy have uncovered the presence of young ($\sim 2-4\,\rm Myr$), massive ($M_\star \sim 10^7\,\rm M_\odot$), and compact ($R_{\rm eff} \sim 8\,\rm pc$) super star clusters. These clusters are characterized by high-pressure, low-metallicity gas ($0.2\,Z_\odot$) with an anomalously elevated nitrogen-to-oxygen ratio $\log ({\rm N/O}) \geq -0.5$, deviating from typical empirical relations. In this talk, we present a suite of three-dimensional magnetohydrodynamic simulations of star formation to investigate analogs of the Sunburst Arc supercluster, which initializes from turbulent giant molecular clouds (GMCs) and evolves for 10 Myr. Our results suggest that the progenitor GMC of such a supercluster may have had a mass of $M_{\rm cl} \geq 3 \times 10^7\,\rm M_\odot$ and a radius of $R_{\rm cl} \sim 70 \pm 10 \,\rm pc$, yielding a high surface density of $\sim 10^3 -10^4\,\rm M_\odot\, pc^{-2}$. By incorporating chemical feedback from individual very massive stars (VMS), we find that stellar winds from these stars can efficiently enrich the surrounding gas with nitrogen. A significant fraction of this enriched gas is funneled toward the cluster center by gravitational collapse, where it undergoes further enrichment and is irradiated by newly forming VMS, creating the high-pressure gas observed. We conclude that the Sunburst Arc supercluster can be naturally explained by star formation in high-density GMCs that considers VMS-driven feedback, potentially providing indirect evidence for a substantial population of VMS in such environments. We further speculate that the mechanism could also apply to high-redshift, nitrogen enriched galaxies and AGNs recently revealed by the JWST.
| Session Selection | Astronomy and Astrophysics |
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