Effects of mass models on dynamical mass estimate: the case of ultradiffuse galaxy NGC 1052-DF2
Effects of mass models on dynamical mass estimate: the case of ultradiffuse galaxy NGC 1052-DF2
复制标题
质量模型对动态质量估计的影响：以超弥散星系 NGC 1052-DF2 为例
DOI：
10.1093/mnrasl/sly162
复制
发表时间：
2018
影响因子：
--
通讯作者：
Inoue Shigeki
中科院分区：
文献类型：
--
作者：
Hayashi Kohei;Inoue Shigeki
NGC 1052-DF2是van Dokkum等人最近发现的缺乏暗物质的星系。然而，由于样本的缺乏、统计方法和距离测量等因素，其动态质量估计存在较大的不确定性。在这项工作中，我们讨论了该星系示踪谱的建模差异对动态质量估计的影响。为了做到这一点，我们假设示踪剂密度是用幂律和sassrsic曲线建模的，然后我们求解球形Jeans方程来估计动态质量。将这些模型应用于NGC 1052-DF2的球状星团的运动学数据，我们比较了从这个分析和van Dokkum等人估计的动态质量光比的90%上限。我们发现幂律得到的上限与van Dokkum等人的结果基本相同，而ssamrsic估计的上限明显大于van Dokkum等人的结果，从而表明NGC 1052-DF2仍然可能是一个以暗物质为主的系统。因此，我们提出星系的动态质量估计在很大程度上不仅受到小运动样本的影响，而且受到示踪剂分布选择的影响，因此估计的质量仍然是相当不确定的。
NGC 1052-DF2 was recently discovered as the dark-matter-deficient galaxy claimed by van Dokkum et al. However, large uncertainties on its dynamical mass estimate have been pointed out, concerning the paucity of sample, statistical methods, and distance measurements. In this work, we discuss the effects of the difference in modelling of the tracer profile of this galaxy on the dynamical mass estimate. To do this, we assume that the tracer densities are modelled with power-law and Sérsic profiles, and then we solve the spherical Jeans equation to estimate the dynamical mass. Applying these models to kinematic data of globular clusters in NGC 1052-DF2, we compare 90 per cent upper limits of dynamical mass-to-light ratios estimated from this analysis and from van Dokkum et al. We find that the upper limit obtained by the power-law is virtually the same as the result from van Dokkum et al, whilst this limit estimated by the Sérsic is significantly greater than that from van Dokkum et al, thereby suggesting that NGC 1052-DF2 can still be a dark-matter-dominated system. Consequently, we propose that dynamical mass estimate of a galaxy is largely affected by not only the small kinematic sample but the choice of tracer distributions, and thus the estimated mass still remains quite uncertain.
了解未知数：银河动力质量简单估计的不确定性。
影响因子：
4.8
作者：
D. Campbell;C. Frenk;A. Jenkins;V. Eke;J. Navarro;Till Sawala;M. Schaller;Azadeh Fattahi;K. Oman;T. Theuns
通讯作者：
T. Theuns
影响因子：
4.8
作者：
Ogiya, Go
通讯作者：
Ogiya, Go
压力支持系统的维里质量估计器的系统学
影响因子：
4.8
作者：
Raphael Errani;J. Peñarrubia;M. Walker
通讯作者：
M. Walker