1. SDSS-IV MaNGA: stellar rotational support in disc galaxies versus central surface density and stellar population age.
- Author
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Wang, Xiaohan, Luo, Yifei, Faber, S M, Koo, David C, Mao, Shude, Westfall, Kyle B, Lu, Shengdong, Wang, Weichen, Bundy, Kevin, Boardman, N, Avila-Reese, Vladimir, Fernández-Trincado, José G, and Lane, Richard R
- Subjects
STELLAR density (Stellar population) ,GALACTIC bulges ,GALACTIC evolution ,DISK galaxies ,GALAXY formation - Abstract
We investigate how the stellar rotational support changes as a function of spatially resolved stellar population age (|$D_n4000$|) and relative central stellar surface density (|$\Delta \Sigma _1$|) for MaNGA isolated/central disc galaxies. We find that the galaxy rotational support indicator |$\lambda _{R_\mathrm{e}}$| varies smoothly as a function of |$\Delta \Sigma _1$| and |$D_n4000$|. |$D_n4000$| versus |$\Delta \Sigma _1$| follows a 'J-shape', with |$\lambda _{R_\mathrm{e}}$| contributing to the scatters. In this 'J-shaped' pattern rotational support increases with central |$D_n4000$| when |$\Delta \Sigma _1$| is low but decreases with |$\Delta \Sigma _1$| when |$\Delta \Sigma _1$| is high. Restricting attention to low- |$\Delta \Sigma _1$| (i.e. large-radius) galaxies, we suggest that the trend of increasing rotational support with |$D_n4000$| for these objects is produced by a mix of two different processes, a primary trend characterized by growth in |$\lambda _{R_\mathrm{e}}$| along with mass through gas accretion, on top of which disturbance episodes are overlaid, which reduce rotational support and trigger increased star formation. An additional finding is that star-forming galaxies with low |$\Delta \Sigma _1$| have relatively larger radii than galaxies with higher |$\Delta \Sigma _1$| at fixed stellar mass. Assuming that these relative radii rankings are preserved while galaxies are star forming then implies clear evolutionary paths in central |$D_n4000$| versus |$\Delta \Sigma _1$|. The paper closes with comments on the implications that these paths have for the evolution of pseudo-bulges versus classical bulges. The utility of using |$\rm D_n4000$| – |$\Delta \Sigma _1$| to study |$\lambda _{R_\mathrm{e}}$| reinforces the notion that galaxy kinematics correlate both with structure and with stellar-population state, and indicates the importance of a multidimensional description for understanding bulge and galaxy evolution. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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