Elliptical Galaxies with Emission Lines from the Sloan Digital Sky Survey

Zhao, Yi; Gu, Qiusheng; Peng, Zhixin; Shi, Lei; Luo, Xiaochun; Peng, Qiu‐He

doi:10.1088/1009-9271/6/1/002

Cited by 4 publications

(1 citation statement)

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“…In the previous work, such as Fukugita et al (2004), Zhao et al (2006) and S07, several EGs have been detected with residual star‐forming activities. In order to isolate weak active galactic nuclei (AGN), EGs are classified by emission lines according to their ionization states estimated from the flux ratios (Baldwin, Phillips & Terlevich 1981; Veilleux & Osterbrock 1987).…”

Section: Data Analysesmentioning

confidence: 88%

Recent star-forming activity in local elliptical galaxies

Huang¹,

Gu²

2009

Monthly Notices of the Royal Astronomical Society

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The formation and evolution of elliptical galaxies (EGs) are still an open question. In particular, recent observations suggest that EGs are not only simple spheroidal systems of old stars. In this paper, we analyse a sample of EGs selected from the Sloan Digital Sky Survey in order to study the star‐forming activity in local EGs. Among these 487 ellipticals, we find that 13 EGs show unambiguous evidence of recent star formation activity betrayed by conspicuous nebular emission lines. Using the evolutionary stellar population synthesis models and Lick absorption line indices, we derive stellar ages, metallicities and α‐element abundances, and thus reconstruct the star formation and chemical evolution history of the star‐forming elliptical galaxies (SFEGs) in our sample. We find that SFEGs have relative younger stellar population age, higher metallicity and lower stellar mass, and that their star formation history can be well described by a recent minor and short starburst superimposed on old stellar component. We also detect 11 E+A galaxies whose stellar population properties are closer to those of quiescent (normal) ellipticals than to star‐forming ones. However, from the analysis of their absorption line indices, we note that our E+A galaxies show a significant fraction of intermediate‐age stellar populations, remarkably different from the quiescent galaxies. This might suggest an evolutionary link between E+As and star‐forming ellipticals. Finally, we confirm the relations between age, metallicity, α‐element abundance and stellar mass for local EGs.

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Section: Data Analysesmentioning

confidence: 88%