Interpreting the first quiescent dwarf galaxy

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The surprising JWST discovery of a quiescent low-mass galaxy at redshift z = 7.3 represent a unique opportunity to study the imprint of feedback processes on early galaxy evolution. To interpret this finding we use the SERRA suite of cosmological zoom-in simulations and built a sample of 130 low-mass galaxies, 30% of which are quiescent.
Gelli, Salvadori et al. ApJ submitted Continue reading Interpreting the first quiescent dwarf galaxy→

PISN signature in the MW Bulge?

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Can we indirectly prove the existence of Pair Instability SuperNovae (PISN)? We demonstrate that the mean [C/Fe] of first stars polluted environments decreases with the increasing contribution of PISNe, and thus with the characteristic mass of the first stars. We conclude that the dearth of C-enhanced metal-poor stars in the Galactic bulge indirectly probes the existence of elusive PISNe, and propose a novel method which exploits this lack to constrain the mass distribution of the first stars.

Pagnini, Salvadori et al. 2023 MNRAS Continue reading PISN signature in the MW Bulge?→

What are C-enhanced metal-poor stars?

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We show that CEMP stars with A(C) > 6 are mainly enriched by AGB Pop II stars. We identify a new class of “moderate CEMP-s stars” with A(C) ~7 and 0 < [Ba/Fe] < + 1, imprinted by winds from AGB stars. Pop III descendants have A(C) < 6 and a constant [C/Mg] with [Fe/H], in perfect agreement with observations in Böotes I and the MW halo. Rossi, Salvadori+2023, MNRAS Letter Continue reading What are C-enhanced metal-poor stars?→