arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1703.00545astro-ph.GA
收藏

The Origin and Evolution of Fast and Slow Rotators in the Illustris Simulation

Zephyr Penoyre, Benjamin P. Moster, Debora Sijacki, Shy Genel

英文摘要:

Using the Illustris simulation, we follow thousands of elliptical galaxies back in time to identify how the dichotomy between fast and slow rotating ellipticals (FRs and SRs) develops. Comparing to the $\textrm{ATLAS}^\textrm{3D}$ survey, we show that Illustris reproduces similar elliptical galaxy rotation properties, quantified by the degree of ordered rotation, $λ_\textrm{R}$. There is a clear segregation between low-mass ($M_{\rm *} < 10^{11} M_{\rm \odot}$) ellipticals, which form a smooth distribution of FRs, and high-mass galaxies ($M_{\rm *} > 10^{11.5} M_{\rm \odot}$), which are mostly SRs, in agreement with observations. We find that SRs are very gas poor, metal rich and red in colour, while FRs are generally more gas rich and still star forming. We suggest that ellipticals begin naturally as FRs and, as they grow in mass, lose their spin and become SRs. While at $z = 1$, the progenitors of SRs and FRs are nearly indistinguishable, their merger and star formation histories differ thereafter. We find that major mergers tend to disrupt galaxy spin, though in rare cases can lead to a spin-up. No major difference is found between the effects of gas-rich and gas-poor mergers and the amount of minor mergers seem to have little correlation with galaxy spin. In between major mergers, lower-mass ellipticals, which are mostly gas-rich, tend to recover their spin by accreting gas and stars. For galaxies with $M_{\rm *}$ above $\sim 10^{11} M_{\rm \odot}$, this trend reverses; galaxies only retain or steadily lose their spin. More frequent mergers, accompanied by an inability to regain spin, lead massive ellipticals to lose most of ordered rotation and transition from FRs to SRs.

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。

↑