http://arxiv.org/abs/2211.09160
Massive ($\geq$8 $M_\odot$) stars perish via one of two fates: core-collapse supernovae (CCSNe), which release synthesized heavy elements, or failed supernovae, thereby forming black holes. In the conventional Galactic chemical evolution (GCE) scheme, a substantial portion of massive stars, e.g., all stars in the mass range of 8-100 $M_{\odot},$ are assumed to enrich the Galaxy with their nucleosynthetic products. However, this hypothesis conflicts with the observations, namely, few CCSNe whose progenitor stars are more massive than $\sim$18 $M_{\odot}.$ Here, we show that the chemical characteristics shaped by local thin disk stars are compatible with the predictions by enrichment via CCSNe limited to less massive progenitors in the new paradigm of Galactic dynamics that allows stars to migrate from the inner disk. This renewed GCE model predicts that the bursting star formation events$-$which are considered to take place in the Galactic bulge as well as in the thick disk$-$generate more numerous low-mass CCSNe than those expected from the locally determined canonical initial mass function. This finding suggests a high rate of CCSNe in early-type galaxies, which reflects a unique cosmic history of the CCSN rate. With considerable contributions from these galaxies to the cosmic star formation rates in the early Universe, we predict a more steeply increasing slope of the CCSN rate with increasing redshift than that in proportion to cosmic star formation. This predicted redshift evolution agrees well with the measured rates for 0 $\lesssim$ z $\lesssim$ 0.8; however, its predicted CCSN rate for higher-$z$ calls for more precise data from future surveys.
T. Tsujimoto
Fri, 18 Nov 22
39/70
Comments: 7 pages including 4 figures, accepted for publication in MNRAS
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