真实模拟星系观测中旋转曲线拟合及其对核心的致命吸引力
Rotation curve fitting and its fatal attraction to cores in realistically simulated galaxy observations
摘要：
我们研究的尖核问题的观测研究的最小光盘近似下使用一套高分辨率（25 PC软化长度）的矮星系流体动力学模拟的系统效应的作用。我们模仿现实的运动学观测和拟合模拟旋转曲线与两个分析模型通常用于区分核心尖点的暗物质分布。我们发现，核心的伪等温球（ISO）模型是强烈青睐的减少$χ^2_ν$的拟合，尽管事实上，我们的模拟包含尖的Navarro-Frenk-White配置文件（NFW）。我们表明，即使理想化的气体圆周运动的测量可能导致不正确的答案，如果速度低估引起的压力支持，一个典型的大小为$\sim$ 5公里s $^{-1}$在中央千秒差距，被忽略。增加模拟观测的空间分辨率会导致更多的误导性结果，因为内部区域，其中压力支持的影响是最显着的，是更好的采样。与空间分辨率为100 pc（10 Mpc时为2 arcsec）的观测结果相吻合，78- 90%的情况下支持ISO模型，而在800 pc分辨率下，40- 78%的星系表明虚构的暗物质核心的存在。我们的最佳拟合模型的系数与观测研究中报道的一致，因此，我们得出结论，NFW晕不能从这种类型的分析可靠地排除。
英文摘要：
We study the role of systematic effects in observational studies of the cusp-core problem under the minimum disc approximation using a suite of high-resolution (25-pc softening length) hydrodynamical simulations of dwarf galaxies. We mimic realistic kinematic observations and fit the mock rotation curves with two analytic models commonly used to differentiate cores from cusps in the dark matter distribution. We find that the cored pseudo-isothermal sphere (ISO) model is strongly favoured by the reduced $χ^2_ν$ of the fits in spite of the fact that our simulations contain cuspy Navarro-Frenk-White profiles (NFW). We show that even idealized measurements of the gas circular motions can lead to the incorrect answer if velocity underestimates induced by pressure support, with a typical size of order $\sim$5 km s$^{-1}$ in the central kiloparsec, are neglected. Increasing the spatial resolution of the mock observations leads to more misleading results because the inner region, where the effect of pressure support is most significant, is better sampled. Fits to observations with a spatial resolution of 100 pc (2 arcsec at 10 Mpc) favour the ISO model in 78-90 per cent of the cases, while at 800-pc resolution, 40-78 per cent of the galaxies indicate the fictitious presence of a dark matter core. The coefficients of our best-fit models agree well with those reported in observational studies; therefore, we conclude that NFW haloes can not be ruled out reliably from this type of analysis.
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