arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2011.13749astro-ph.GA
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局域宇宙中大质量红旋涡星系的恒星形成历史

Star formation histories of massive red spiral galaxies in the local universe

Shuang Zhou, Cheng Li, Cai-Na Hao, Rui Guo, Houjun Mo, Xiaoyang Xia

摘要:

研究了恒星质量为$M_\ast>10^{10.5}M_\odot$的大质量红色旋涡星系的恒星形成历史,并与质量相近的蓝色旋涡星系和红色椭圆星系进行了比较。我们利用积分场光谱从SDSS-IV/DR 15的MaNGA样品,并估计空间分辨SFH和恒星星族属性的每个星系通过应用贝叶斯光谱拟合代码的MaNGA光谱。我们发现红螺旋星系和红椭圆星系在早期都只经历过一次主要的恒星形成事件,并且这一结果与所采用的SFH模型无关。平均而言,它们的恒星质量中有一半以上是在10 Gyrs前形成的,而90%以上是在$>$ Gyrs前形成的。这两种类型的星系在不同的恒星星族参数上显示出相似的平坦轮廓:由$D4000$表示的老恒星年龄(光谱突变在4000 nm左右),高恒星金属丰度,大的Mgb/Fe比率表明快速形成,以及很少的恒星尘埃衰减。相比之下,虽然蓝色螺旋也在10 Gyrs前形成了它们的中心区域$>$,但它们的中心区域和外部盘都在很长的时间尺度上不断形成恒星。我们的研究结果表明,大质量红旋涡与大质量红椭圆星系可能有一些共同的形成过程(也可能是淬灭过程),即两种类型都是在$z > 2$通过快速形成过程形成的,并讨论了大质量红旋涡形成和淬灭的可能机制.

英文摘要:

We investigate the star formation histories (SFHs) of massive red spiral galaxies with stellar mass $M_\ast>10^{10.5}M_\odot$, and make comparisons with blue spirals and red ellipticals of similar masses. We make use of the integral field spectroscopy from the SDSS-IV/DR15 MaNGA sample, and estimate spatially resolved SFHs and stellar population properties of each galaxy by applying a Bayesian spectral fitting code to the MaNGA spectra. We find that both red spirals and red ellipticals have experienced only one major star formation episode at early times, and the result is independent of the adopted SFH model. On average, more than half of their stellar masses were formed $>$10 Gyrs ago, and more than 90\% were formed $>6$ Gyrs ago. The two types of galaxies show similarly flat profiles in a variety of stellar population parameters: old stellar ages indicated by $D4000$ (the spectral break at around 4000Å), high stellar metallicities, large Mgb/Fe ratios indicating fast formation, and little stellar dust attenuation. In contrast, although blue spirals also formed their central regions $>$10 Gyrs ago, both their central regions and outer disks continuously form stars over a long timescale. Our results imply that, massive red spirals are likely to share some common processes of formation (and possibly quenching) with massive red ellipticals in the sense that both types were formed at $z > 2$ through a fast formation process.Possible mechanisms for the formation and quenching of massive red spirals are discussed.

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