论文标题
伊卡洛斯：银河系磁盘中的平坦而快速的前列恒星流
Icarus: a Flat and Fast Prograde Stellar Stream in the Milky Way disk
论文作者
论文摘要
我们通过化学和运动学测量值探索了银河系的局部体积，该测量来自Gaia，Apogee和Galah程序最近发布的高质量的星体和光谱数据。 我们从化学上选择了$ 1137 $的星星，最高$ 2.5 $ 〜kpc的太阳和$ \ rm {[fe/h]} \ le -1.0 $ 〜DEX，并找到具有统计学意义的子结构的证据。速度空间中的聚类分析将$ 163 $的对象分为八个运动组，其起源是通过单个合并事件的高分辨率N体数值模拟进一步研究的。 这两个逆行组似乎与Gaia-Sausage-cenceladus有关，而略微的前列组可以连接到GSE或Wukong。 我们找到了我们命名Icarus的新的44名成员的前列过程的证据；据我们所知，iCarus是迄今为止最接近银河系磁盘的快速旋转流（$ \ langle z _ {\ rm max} \ rangle \ lysesim 0.5 $ 〜kpc，$ \ langle v+v+v+v _ { 231〜 \ rm {km〜s^{ - 1}} $）。它的特殊化学物质（$ \ langle \ rm {[fe/h]} \ rangle \ simeq -1.45 $，$ \ langle \ rm {[mg/fe]} \ rangle \ rangle \ simeq -0.02 $）和动态（平均值$ \ simeq acime $ \ simeq a properies at acimeq acimeq acimeq acimeq acimeq a properies are perties arty atimenties arty ate ate atie ate a prathies at de aperies at de a prate at de aperies at de aperies是矮星祖先在初始前列轨道上具有$ \ sim 10^9 m_ \ sun $的恒星质量，$ \ sim 10^\ circ $。 剩余的前列组是先前由伊卡洛斯（或NYX）的祖细胞释放的流，或者是在较高倾斜度下在初始轨道上积聚的不同卫星的残余物。
We explore the local volume of the Milky Way via chemical and kinematical measurements from high quality astrometric and spectroscopic data recently released by the Gaia, APOGEE and GALAH programs. We chemically select $1137$ stars up to $2.5$~kpc of the Sun and $\rm{[Fe/H]} \le -1.0$~dex, and find evidence of statistically significant substructures. Clustering analysis in velocity space classifies $163$ objects into eight kinematical groups, whose origin is further investigated with high resolution N-body numerical simulations of single merging events. The two retrograde groups appear associated with Gaia-Sausage-Enceladus, while the slightly prograde group could be connected to GSE or possibly Wukong. We find evidence of a new 44-member-strong prograde stream we name Icarus; to our knowledge, Icarus is the fast-rotating stream closest to the Galactic disk to date ($\langle Z_{\rm max} \rangle \lesssim 0.5$~kpc, $\langle V+V_{\rm{LSR}}\rangle \simeq 231~\rm{km~s^{-1}}$). Its peculiar chemical ($\langle \rm{[Fe/H]}\rangle \simeq -1.45$, $\langle \rm{[Mg/Fe]}\rangle \simeq -0.02$) and dynamical (mean eccentricity $\simeq 0.11$) properties are consistent with the accretion of debris from a dwarf galaxy progenitor with a stellar mass of $\sim 10^9 M_\sun$ on an initial prograde low-inclination orbit, $\sim 10^\circ$. The remaining prograde groups are either streams previously released by the same progenitor of Icarus (or Nyx), or remnants from different satellites accreted on initial orbits at higher inclination.
