A relation between the characteristic stellar ages of galaxies and their intrinsic shapes
Stellar population and stellar kinematic studies provide unique but complementary insights into how galaxies build-up their stellar mass and angular momentum 1-3 . A galaxy's mean stellar age reveals when stars were formed, but provides little constraint on how the galaxy's mass was assemb...
Published in: | Nature Astronomy |
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Main Authors: | , , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2018
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Subjects: | |
Online Access: | https://researchers.mq.edu.au/en/publications/956fbba9-8023-4896-81f4-2bfc279e74a4 https://doi.org/10.1038/s41550-018-0436-x http://www.scopus.com/inward/record.url?scp=85048114651&partnerID=8YFLogxK http://purl.org/au-research/grants/arc/CE170100013 |
Summary: | Stellar population and stellar kinematic studies provide unique but complementary insights into how galaxies build-up their stellar mass and angular momentum 1-3 . A galaxy's mean stellar age reveals when stars were formed, but provides little constraint on how the galaxy's mass was assembled. Resolved stellar dynamics 4 trace the change in angular momentum due to mergers, but major mergers tend to obscure the effect of earlier interactions 5 . With the rise of large multi-object integral field spectroscopic surveys, such as SAMI 6 and MaNGA 7 , and single-object integral field spectroscopic surveys (for example, ATLAS 3D (ref. 8 ), CALIFA 9 , MASSIVE 10 ), it is now feasible to connect a galaxy′s star formation and merger history on the same resolved physical scales, over a large range in galaxy mass, morphology and environment 4,11,12 . Using the SAMI Galaxy Survey, here we present a combined study of spatially resolved stellar kinematics and global stellar populations. We find a strong correlation of stellar population age with location in the (V/σ, ϵe) diagram that links the ratio of ordered rotation to random motions in a galaxy to its observed ellipticity. For the large majority of galaxies that are oblate rotating spheroids, we find that characteristic stellar age follows the intrinsic ellipticity of galaxies remarkably well. |
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