LAMOST DR9中的强[ OIII ]λ5007发射线致密星系：蓝莓、绿豌豆和紫葡萄
Strong [OIII]λ5007 emission line compact galaxies in LAMOST DR9: Blueberries, Green Peas and Purple Grapes
摘要：
豌豆星系和蓝莓星系以其紧凑的尺寸、低质量、强发射线以及与高z Lyα发射星系的类似物而闻名。本研究从LAMOST DR 9中选取了1547个红移范围为0.0 ~ 0.59的强[OIII]λ5007发射线致密星系，共获得1694条光谱。根据红移分布，这些样品可以分为三类：蓝莓，青豆和紫葡萄。利用[MgII]λ2800光学谱线特征、BPT图、多波长SED拟合、MIR颜色和MIR变率，从这些样品中识别出23个活动星系核候选者，这些候选者将被排除在下面的SFR讨论之外。我们用GALEX UV和WISE MIR数据进行了多波长SED拟合。Balmer衰减的颜色过剩表明，这些强[OIII]λ5007发射线致密星系不是高度红化的。星系的恒星质量是通过拟合LAMOST校准光谱与屏蔽的发射线。我们发现SFR随红移的增加而增加，而对于同一红移仓内的源，SFR随质量的增加具有与SFMS相似的斜率。这些样品的金属丰度中值为12+log（O/H）8.10。金属丰度随质量的增加而增加，所有来源都低于质量-金属丰度关系。从[OIII]λ4363线直接导出的Te基金属丰度与经验N2基经验气相金属丰度一致。此外，这些致密的强[OIII]λ5007大多处于密度较低的环境中。
英文摘要：
Green Pea and Blueberry galaxies are well-known for their compact size, low mass, strong emission lines and analogs to high-z Lyα emitting galaxies. In this study, 1547 strong [OIII]λ5007 emission line compact galaxies with 1694 spectra are selected from LAMOST DR9 at the redshift range from 0.0 to 0.59. According to the redshift distribution, these samples can be separated into three groups: Blueberries, Green Peas and Purple Grapes. Optical [MgII]λ2800 line feature, BPT diagram, multi-wavelength SED fitting, MIR color, and MIR variability are deployed to identify 23 AGN candidates from these samples, which are excluded for the following SFR discussions. We perform the multi-wavelength SED fitting with GALEX UV and WISE MIR data. Color excess from Balmer decrement shows these strong [OIII]λ5007 emission line compact galaxies are not highly reddened. The stellar mass of the galaxies is obtained by fitting LAMOST calibrated spectra with the emission lines masked. We find that the SFR is increasing with the increase of redshift, while for the sources within the same redshift bin, the SFR increases with mass with a similar slope as the SFMS. These samples have a median metallicity of 12+log(O/H) of 8.10. The metallicity increases with mass, and all the sources are below the mass-metallicity relation. The direct-derived Te-based metallicity from the [OIII]λ4363 line agrees with the empirical N2-based empirical gas-phase metallicity. Moreover, these compact strong [OIII]λ5007 are mostly in a less dense environment.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
