论文标题

Nihao模拟中超弥漫星系的金属度曲线

Metallicity profiles of Ultra Diffuse Galaxies in NIHAO simulations

论文作者

Cardona-Barrero, S., Di Cintio, A., Battaglia, G., Macciò, A. V., Taibi, S.

论文摘要

Supernovae反馈驱动的扩张已被证明是解释超弥漫星系(UDGS)的平均特性的可行机制,例如大小,颜色,质量和内部运动学。在这里,我们探索了Nihao项目反馈驱动的模拟UDG中恒星金属性梯度的起源,并将它们与观察到的本地组矮人的金属性梯度以及最近观察到的UDG DF44的分布进行了比较。模拟的UDG显示了各种各样的金属度曲线,显示出平坦至负梯度,类似于LG矮人中观察到的梯度,而DF44数据则表明平坦至正梯度。模拟中的多种金属性梯度是通过恒星形成的半径与随后的超新星反馈反馈驱动的恒星重新分配的相互作用来设定的:旋转支持的系统倾向于具有平坦的金属曲线,而分散支持的星系支持星系为负和陡峭的轮廓。 我们的结果表明,与常规矮人相比,UDG在其金属性梯度方面并不是特殊的。尤其是,将来应提供更大的UDGS梯度的观察样本,以测试我们的预测。

Supernovae feedback driven expansion has proven to be a viable mechanism to explain the average properties of Ultra Diffuse Galaxies (UDGs) such as the sizes, colors, mass and internal kinematics. Here, we explore the origin of stellar metallicity gradients in feedback driven simulated UDGs from the NIHAO project and compare them with the observed distribution of metallicity gradients of both Local Group dwarfs as well as of the recently observed UDG DF44. Simulated UDGs display a large variety of metallicity profiles, showing flat to negative gradients, similarly to what is observed in LG dwarfs, while DF44 data suggest a flat to positive gradient. The variety of metallicity gradients in simulations is set by the interplay between the radius at which star formation occurs and the subsequent supernovae feedback driven stellar redistribution: rotation supported systems tend to have flat metallicity profiles while dispersion supported galaxies show negative and steep profiles. Our results suggest that UDGs are not peculiar in what regards their metallicity gradients, when compared to regular dwarfs. Desirably, a larger observational sample of UDGs' gradients shall be available in the future, in order to test our predictions.

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