arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1902.05955astro-ph.GA
收藏

盘星系化学演化的宇宙学模拟

Chemical evolution of disc galaxies from cosmological simulations

Milena Valentini, Stefano Borgani, Alessandro Bressan, Giuseppe Murante, Luca Tornatore, Pierluigi Monaco

摘要:

我们进行了一套盘星系的宇宙学流体动力学模拟,放大的初始条件导致形成的质量$M_{\rm halo, \, DM} \simeq 2 \cdot 10^{12}$ M $_{\odot}$在红移$z=0$的晕。这些模拟的目的是研究盘状星系中金属的化学演化和分布,并量化$(i)$(假设的IMF)、$(ii)$(采用的恒星产额)和$(iii)$(起源于SNe Ia的双星系统对化学富集过程的影响)的影响。我们考虑Kroupa et al.(1993)或更头重脚轻的Kroupa(2001)IMF,两组恒星产额和适合产生Ia型超新星的双星系统比例的不同值。我们调查恒星年龄,SN率,恒星和气体金属丰度梯度,恒星$α$ -模拟增强,并与观测比较预测。我们发现,Kroupa等(1993)IMF的晚型星系在本地宇宙中的建模时,必须首选。另一方面,恒星金属丰度剖面和$α$增强趋势与银河系恒星观测结果的比较表明,当假设Kroupa(2001)IMF时,两者的一致性更好。比较预测的SN率和恒星$α$ -增强与观测支持的分数的二进制系统生产SNe Ia的$0.03$,至少对于晚型星系和所考虑的IMF。采用恒星产额是至关重要的调节冷却和恒星的形成,并在确定模式的化学富集的恒星,特别是那些位于星系的隆起。

英文摘要:

We perform a suite of cosmological hydrodynamical simulations of disc galaxies, with zoomed-in initial conditions leading to the formation of a halo of mass $M_{\rm halo, \, DM} \simeq 2 \cdot 10^{12}$ M$_{\odot}$ at redshift $z=0$. These simulations aim at investigating the chemical evolution and the distribution of metals in a disc galaxy, and at quantifying the effect of $(i)$ the assumed IMF, $(ii)$ the adopted stellar yields, and $(iii)$ the impact of binary systems originating SNe Ia on the process of chemical enrichment. We consider either a Kroupa et al. (1993) or a more top-heavy Kroupa (2001) IMF, two sets of stellar yields and different values for the fraction of binary systems suitable to give rise to SNe Ia. We investigate stellar ages, SN rates, stellar and gas metallicity gradients, and stellar $α$-enhancement in simulations, and compare predictions with observations. We find that a Kroupa et al. (1993) IMF has to be preferred when modelling late-type galaxies in the local universe. On the other hand, the comparison of stellar metallicity profiles and $α$-enhancement trends with observations of Milky Way stars shows a better agreement when a Kroupa (2001) IMF is assumed. Comparing the predicted SN rates and stellar $α$-enhancement with observations supports a value for the fraction of binary systems producing SNe Ia of $0.03$, at least for late-type galaxies and for the considered IMFs. Adopted stellar yields are crucial in regulating cooling and star formation, and in determining patterns of chemical enrichment for stars, especially for those located in the galaxy bulge.

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。

↑