论文标题
银河系矮小的矮小的光环外缘:首先坠落还是后挡板卫星?
Dwarfs in the Milky Way halo outer rim: first in-fall or backsplash satellites?
论文作者
论文摘要
狮子座是一个富含气体的矮人,位于414kpc $(1.4r _ {\ rm vir})$距离银河系(MW)的距离,目前被认为是其第一种方法。在这里,我们通过我们的新代码{\ sc delorean}对矮人的及时计算的轨道进行了分析,探索了一系列系统的不确定性,例如。 MW病毒质量和积聚,M31电位和宇宙扩张。我们发现,在银河标准框架中具有切向速度的轨道低于$ | \ vec {u} _ {\ rm t}^{\ rm gsr} | \!\!\ leq \! 63^{+47} _ { - 39} {\ rm \,km \,km \,s^{ - 1}} $导致Backsplash Solutions,即过去输入并留下MW Dark Matter Halo的轨道,并在过去的速度上及以上的速度,以及$ | \ vec | \ vec {u} _} gsr} | \!\ geq \!21^{+33} _ { - 21} {\ rm \,km \,km \,s^{ - 1}} $在宽阔的backsplashslash solutions中,最小围端范围为$ d _ {\ rm $ d _ {\ rm min} \!\ geq \!38^{+26} _ { - 16} {\ rm \,kpc} $,这将使该卫星能够在气体剥离和潮汐破坏中生存。此外,新的适当运动估计与我们的后挡解决方案区域相匹配。我们将方法应用于其他遥远的MW卫星,找到了一系列用于无气的CETUS和ERIDANUS II的反向挡板解决方案,为它们缺乏冷气提供了一种可能的解释,而仅针对Hi Rich Phoenix发现了第一次倒置解决方案。我们还发现,宇宙扩张可以延迟其第一次percenteral percenters vestect and-expect ancect ancect and-expect and-expect and-expect and-expect。这项研究探讨了这些遥远的矮人的出处,并对塑造其演变和当前特性的环境和内部过程提供了约束。
Leo T is a gas-rich dwarf located at 414kpc $(1.4R_{\rm vir})$ distance from the Milky Way (MW) and it is currently assumed to be on its first approach. Here, we present an analysis of orbits calculated backward in time for the dwarf with our new code {\sc delorean}, exploring a range of systematic uncertainties, e.g. MW virial mass and accretion, M31 potential, and cosmic expansion. We discover that orbits with tangential velocities in the Galactic Standard-of-Rest frame lower than $|\vec{u}_{\rm t}^{\rm GSR}|\!\leq\! 63^{+47}_{-39}{\rm\, km\, s^{-1}}$ result in backsplash solutions, i.e. orbits that entered and left the MW dark matter halo in the past, and that velocities above $|\vec{u}_{\rm t}^{\rm GSR}|\!\geq\!21^{+33}_{-21}{\rm\, km\, s^{-1}}$ result in wide orbit backsplash solutions with a minimum pericenter range of $D_{\rm min}\!\geq\!38^{+26}_{-16}{\rm \,kpc}$, which would allow this satellite to survive gas stripping and tidal disruption. Moreover, new proper motion estimates match with our region of backsplash solutions. We applied our method to other distant MW satellites, finding a range of gas stripped backsplash solutions for the gas-less Cetus and Eridanus II, providing a possible explanation for their lack of cold gas, while only first in-fall solutions are found for the HI rich Phoenix I. We also find that the cosmic expansion can delay their first pericenter passage when compared to the non-expanding scenario. This study explores the provenance of these distant dwarfs and provides constraints on the environmental and internal processes that shaped their evolution and current properties.