SDSS-IV MaNGA: Bayesian analysis of the star formation history of low-mass galaxies in the local Universe
SDSS-IV MaNGA: Bayesian analysis of the star formation history of low-mass galaxies in the local Universe
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DOI：
10.1093/mnras/staa2337
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发表时间：
2020-03
影响因子：
4.8
通讯作者：
Shuang Zhou;H. Mo;Cheng Li;M. Boquien;G. Rossi
中科院分区：
文献类型：
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作者：
Shuang Zhou;H. Mo;Cheng Li;M. Boquien;G. Rossi
我们测量了来自SDSS-IV MaNGA巡天的一个M* < 109 M的低质量星系样本的星星形成历史。每个星系的大量IFU光谱要么被组合以达到高信噪比，要么被用来研究空间变化。我们使用基于全谱拟合的贝叶斯推断。我们的分析贝叶斯证据比的基础上表明，一个强烈的偏好的模型，允许存在一个老的恒星人口，和一个不适当的模型SFH可以显着低估这些星系中的老人口。在约束数据中加入近红外测光可以进一步区分不同的SFH模型族，并显着收紧对旧总体质量分数的约束。平均而言，现今低质量星系中超过一半的恒星质量至少在8 Gyr前形成，而大约30%的恒星质量在过去的4 Gyr内形成。卫星星系平均比中央星系更早形成恒星质量。SFH的径向依赖性很弱。我们的研究结果表明，大多数低质量星系都有一个活跃的星星形成的早期插曲，产生了它们现在恒星质量的很大一部分。
We measure the star formation histories (SFHs) of a sample of low-mass galaxies with M* < 109 M⊙ from the SDSS-IV MaNGA survey. The large number of IFU spectra for each galaxy are either combined to reach a high signal to noise ratio or used to investigate spatial variations. We use Bayesian inferences based on full spectrum fitting. Our analysis based on Bayesian evidence ratio indicates a strong preference for a model that allows the presence of an old stellar population, and that an improper model for the SFH can significantly underestimate the old population in these galaxies. The addition of near-infrared photometry to the constraining data can further distinguish between different SFH model families and significantly tighten the constraints on the mass fraction in the old population. On average more than half of the stellar mass in present-day low-mass galaxies formed at least 8 Gyr ago, while about 30 per cent within the past 4 Gyr. Satellite galaxies on average have formed their stellar mass earlier than central galaxies. The radial dependence of the SFH is quite weak. Our results suggest that most of the low-mass galaxies have an early episode of active star formation that produces a large fraction of their present stellar mass.