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arXiv · 2305.09191

Ionized gas metallicity of the strong [OIII]{\lambda} emission-line compact galaxies in the LAMOST survey

Siqi Liu·A-Li Luo·Wei Zhang·Xiao Kong·Yong-Heng Zhao
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Abstract

This article reports a sample of 1830 strong [O III] {\lambda}5007 emission-line compact galaxies discovered with the LAMOST spectroscopic survey and the photometric catalog of SDSS. We newly identify 402 spectra of 346 strong [O III]{\lambda}5007 emission-line compact galaxies by finding compact isolated point sources. Combined with the samples in our previous work (Liu et al. 2022), this returns a sample of 1830 unique strong [O III]{\lambda}5007 emission-line compact galaxies with 2033 spectra of z <= 0.53. For the sources with 2{\sigma} [OIII]{\lambda}4363 detections, we calculate the gas-phase metallicity with the direct-Te method, and verify that the strong-line metallicity diagnostics calibrated with the direct-Te method also applies to this sample. The strong [O III]{\lambda}5007 emission-line compact galaxies fall below several Te-calibrated mass-metallicity relations. The N/O measurements of the strong [O iii]{\lambda}5007 emission-line compact galaxies mainly locate at a plateau at low metallicity, indicating the product of primary nucleosynthesis. The Ne3O2 and O32 relation follows a tight linear relation with no redshift evolution. The Ne3O2 anti-correlates with the stellar mass, and at fixed stellar mass the Ne3O2 increase with the redshift. Eight sources with asymmetric [O III]{\lambda}5007 emission-line profiles have been identified, however with no [O III]{\lambda}4363 detection, which proves the rich metal content and complex ionized gas kinematics within the galaxies. Higher-resolution spectroscopy will be necessary to identify the ionized gas components in detail.

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Siqi Liu, A-Li Luo, Wei Zhang, Xiao Kong, Yong-Heng Zhao. 2023-05-16. Ionized gas metallicity of the strong [OIII]{\lambda} emission-line compact galaxies in the LAMOST survey. https://doi.org/10.3847/1538-4365/acd69c

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