测试[O II]λ3727作为类星体宿主星系中恒星形成率示踪剂的可行性
Testing [O II] $\lambda3727$ as a Star Formation Rate Tracer in Quasar Host Galaxies
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中文总结 AI 辅助
研究测试[O II]λ3727作为类星体宿主星系恒星形成率示踪剂的可靠性，通过比较202个类星体样本的[O II] SFR与参考FIR SFR，经光谱拟合、校正等处理，得出相关偏移情况，表明其可作统计示踪剂，但个别对象需处理多种误差。
中文摘要 AI 辅助
[O II]λ3727发射线是广泛使用的恒星形成率（SFR）示踪剂。但将其应用于I型类星体并不简单，因该谱线会受尘埃消光、金属丰度和AGN窄线区（NLR）污染影响。本文通过比较202个SDSS和PG类星体样本的[O II] SFR与多波段SED分解得出的远红外（FIR）参考SFR，测试[O II] SFR的可靠性。经光谱拟合测量[O II]、[O III]和窄巴尔末发射线，校正尘埃消光和金属丰度后计算[O II] SFR，并与FIR SFR比较。结果表明校正后全样本和特定信噪比源的[O II]与FIR SFR的中值偏移情况。结论是[O II]可作为类星体宿主星系统计SFR示踪剂，但个别对象仍需仔细处理AGN污染、消光、金属丰度、孔径效应和红移相关系统误差。
英文摘要
The [O II] $\lambda3727$ emission line is a widely used star formation rate (SFR) tracer. However, its application to type I quasars is not straightforward, because the line can be affected by dust extinction, metallicity and contamination from the AGN narrow-line region (NLR). We test the reliability of [O II] SFRs using a sample of 202 SDSS and PG quasars, by comparing [O II] SFRs and reference far-infrared (FIR) SFRs derived from multiwavelength SED decomposition. We measure [O II], [O III], and narrow Balmer emission lines by spectral fitting. Then, we calculate [O II] SFRs after correcting dust extinction and metallicity. We then compare these SFRs with the FIR SFRs, both with and without subtracting the AGN contribution estimated from [O III]. After this correction, the median offset between [O II] and FIR SFRs is $-0.20\pm0.72$ dex for the full analysis sample and $-0.17\pm0.69$ dex for sources with S/N $>5$ in both [O II] and [O III]. Without subtracting the AGN contribution, the corresponding offsets are $0.00\pm0.69$ and $0.12\pm0.66$ dex. We conclude that [O II] is useful as a statistical SFR tracer for quasar host galaxies, but individual objects still require careful treatment of AGN contamination, extinction, metallicity, aperture effects, and redshift-dependent systematics.
