论文标题
球状簇在cuspy fornax中的生存
The survival of globular clusters in a cuspy Fornax
论文作者
论文摘要
长期以来一直有人争辩说，Fornax Dwarf Galaxy中球形簇（GC）的径向分布要求其暗物质光环具有大小$ \ sim 1 $ kpc的核心。我们通过研究在E-Mosaics中形成的Fornax的类似物来重新审视这一论点，这是一种宇宙学水动力学模拟，它自愿遵循Eagle Galaxy形成模型中GC的形成和演变。在Eagle中，Fornax-Mas Haloes cuspy且由Navarro-Frenk-White曲线很好地描述。我们后处理电子模型是为了解释动态摩擦的GC轨道衰变，该摩擦未包含在原始模型中。动态摩擦会导致33％的GC带有质量$ M _ {\ rm GC} \ geq4 \ geq4 \ times10^4 {〜\ rm m_ \ odot} $沉没到他们的主机中心，在他们潮湿的地方。 Fornax共有五个GC，与其他类似恒星质量的星系相比，数量非常大。在模拟中，我们发现只有3％的FORNAX类似物具有五个或更多的GC，而30％的类似物只有一个和35％的GC没有。我们发现，卫星中的GC系统比矮人中的集中浓缩更加集中，并且与原位形成的GC系统相比，原位形成的卫星比被吸收的卫星更集中。 GC的生存概率随着其形成的径向距离（$ r _ {\ rm Init} $）的迅速增加：对于带有$ r _ {\ rm Init} \ leq 1 $ kpc的GC的GC为37％，使用$ rm _ rm _ rm _ rm _ rm rm rm rm rm iits} $ rm rm rm rm rm nit} $ kpc 1 $ kp \ geq 1 $ kpc。 E-Mosaics中GC的当今径向分布与Fornax中的径向分布没有区别，这表明，与文献中的主张相反，Fornax中央的千层次中存在五个GC并不排除cuspy dm halo。
It has long been argued that the radial distribution of globular clusters (GCs) in the Fornax dwarf galaxy requires its dark matter halo to have a core of size $\sim 1$ kpc. We revisit this argument by investigating analogues of Fornax formed in E-MOSAICS, a cosmological hydrodynamical simulation that self-consistently follows the formation and evolution of GCs in the EAGLE galaxy formation model. In EAGLE, Fornax-mass haloes are cuspy and well described by the Navarro-Frenk-White profile. We post-process the E-MOSAICS to account for GC orbital decay by dynamical friction, which is not included in the original model. Dynamical friction causes 33 per cent of GCs with masses $M_{\rm GC}\geq4\times10^4 {~\rm M_\odot}$ to sink to the centre of their host where they are tidally disrupted. Fornax has a total of five GCs, an exceptionally large number compared to other galaxies of similar stellar mass. In the simulations, we find that only 3 per cent of the Fornax analogues have five or more GCs, while 30 per cent have only one and 35 per cent have none. We find that GC systems in satellites are more centrally concentrated than in field dwarfs, and that those formed in situ (45 per cent) are more concentrated than those that were accreted. The survival probability of a GC increases rapidly with the radial distance at which it formed ($r_{\rm init}$): it is 37 per cent for GCs with $r_{\rm init} \leq 1$ kpc and 92 per cent for GCs with $r_{\rm init} \geq 1$ kpc. The present-day radial distribution of GCs in E-MOSAICS turns out to be indistinguishable from that in Fornax, demonstrating that, contrary to claims in the literature, the presence of five GCs in the central kiloparsec of Fornax does not exclude a cuspy DM halo.
