천문학회보 (The Bulletin of The Korean Astronomical Society)
- 제45권1호
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- Pages.63.1-63.1
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- 2020
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- 1226-2692(pISSN)
Effect of Recent Star Formation of Galaxies on their Chemical Abundance Estimation
- Yoo, Dasol (Department of Astronomy, Yonsei University) ;
- Chung, Chul (Department of Astronomy, Yonsei University) ;
- Na, Chongsam (Department of Astronomy, Yonsei University) ;
- Moon, Jun-Sung (Department of Astronomy, Yonsei University) ;
- Yoon, Suk-Jin (Department of Astronomy, Yonsei University)
- 발행 : 2020.10.13
초록
We investigate the effect of recent star formation (RSF) on the α-elements-to-iron ratio ([α/Fe]) estimation for galaxies. Measuring galactic [α/Fe] is a powerful tool to pinpointing the timescale of chemical evolution and star formation. Our working hypothesis is that, with increasing stellar surface temperature, absorption equivalent width (EW) of α-elements decreases faster than that of Fe-peak elements, and thus RSF will lower the line ratio of EW(α)/EW(Fe). Moreover, young stars outshine, effectively lowering EW(α)/EW(Fe) of integrated light of RSF galaxies. Here we test our hypothesis using SDSS (optical spectrophotometric), GALEX (UV photometric) and IllustrisTNG datasets, and show that, if RSF is not considered thoroughly, EW(α)/EW(Fe) lowered by RSF can be routinely misinterpreted as low [α/Fe]. We discuss possible implications of the result in the context of the conventional [α/Fe]-mass relation of galaxies.
키워드