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This study examines the neutral hydrogen gas content of lenticular (S0) galaxies, comparing star-forming S0s (SFS0s) to quiescent S0s (qS0s) and spiral galaxies using data from the MaNGA survey. The research finds that SFS0s have intermediate hydrogen properties between qS0s and spirals but are more similar to spirals, and that SFS0s have significantly lower masses than qS0s. The findings suggest that SFS0s and qS0s represent two distinct evolutionary populations with different formation pathways, rather than SFS0s being a transitional phase that evolves into qS0s.
Why it matters
This research clarifies the evolutionary pathways of lenticular galaxies, which are important for understanding how galaxies transition from active star formation to quiescence. The findings challenge simple linear models of galaxy evolution and suggest that galaxy mass plays a critical role in determining evolutionary outcomes.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: Lenticular (S0) galaxies that remain actively star-forming (SFS0s) are a unique transition population among galaxies. We investigated the HI (21cm) neutral hydrogen content of a sample of lenticular galaxies identified from within the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey and which have been classified as star-forming or quiescent (qS0s). We compared these populations to each other and to a sample of star-forming spiral (SFSp) galaxies in MaNGA. We found that the HI mass fraction and HI deficiency of the SFS0s were intermediate between the qS0s and the SFSps, but more similar to the spirals. The HI depletion time of the qS0s is very much longer than that of the SFS0s and spirals, which have roughly similar times. We also compared the molecular gas fractions of the three groups which shows that the lowest fraction of the three populations is found in the qS0s, followed by the SFS0s and then the SFSps. A comparison of total baryonic mass indicates that the SFS0s have significantly lower masses than the qS0s in the sample. This suggests that the SFS0s must form from lower mass progenitors (unobserved by MaNGA) which either accrete external gas or lose spiral arms. The more massive qS0s are a completely separate population, most likely to be formed either from fading SFSps or from medium- to high-mass spirals undergoing mergers. The SFS0s in this sample cannot form from the qS0s in this sample that receive in-falling gas, nor can they fade to create these qS0s.
Source: The Neutral Hydrogen Gas Content of Star-forming and Quiescent S0 Galaxies