Systematics in virial mass estimators for pressure-supported systems
Systematics in virial mass estimators for pressure-supported systems
复制标题
压力支持系统的维里质量估计器的系统学
DOI：
--
复制
发表时间：
2018
影响因子：
4.8
通讯作者：
M. Walker
中科院分区：
文献类型：
--
作者：
Raphael Errani;J. Peñarrubia;M. Walker
质量估计是推断暗物质含量的关键工具，在压力支持的系统，如矮球状星系（dSphs）。我们基于维里定理构建了一个封闭质量的估计器，该定理对速度色散中的各向异性不敏感，并被定制为产生具有最小不确定性的质量，这些不确定性是由我们对（i）内晕轮廓的形状以及（ii）恒星组件嵌入晕内的深度引起的：$M（<1.8\，R_h}）\approximately 3.5 \times 1.8\，R_h} \langle \sigma_\mathrm{los}^2 \rangle G^{-1}$，其中，$R_\mathrm{h}$表示投影半光半径，$\langle \sigma_\mathrm{los}^2 \rangle$表示亮度平均平方线，视速度色散对控制模拟测试表明，该估计提供了无偏封闭群众的准确性为$\sim 10$百分之。这证实了以前提出的类似质量估计的鲁棒性。银河系dSphs公布的运动学数据的应用程序揭示了封闭的质量和光度之间的紧密相关性。使用$N$体模型，我们表明，潮汐剥离这种关系的影响不大。与从宝瓶座A2合并树的受控再模拟中提取的尖状和核心暗物质晕的比较表明，超暗星系的高质量密度与大的暗物质核心不相容，并且经典银河系dSphs的（总）晕质量跨度非常窄（$8 \lesssim \mathrm{log_{10}}\，（M/\mathrm{M_\odot}）\lesssim 10$），没有显示出星系大小或光度的明显趋势。
Mass estimators are a key tool to infer the dark matter content in pressure-supported systems like dwarf spheroidal galaxies (dSphs). We construct an estimator for enclosed masses based on the virial theorem which is insensitive to anisotropy in the velocity dispersion and tailored to yield masses with minimum uncertainty introduced by our ignorance on (i) the shape of the inner halo profile, and (ii) how deeply the stellar component is embedded within the halo: $M(<1.8\,R_\mathrm{h}) \approx 3.5 \times 1.8\,R_\mathrm{h} \langle \sigma_\mathrm{los}^2 \rangle G^{-1}$, where by $R_\mathrm{h}$ we denote the projected half-light radius and by $\langle \sigma_\mathrm{los}^2 \rangle$ the luminosity-averaged squared line-of-sight velocity dispersion. Tests against controlled simulations show that this estimator provides unbiased enclosed masses with an accuracy of $\sim 10$ per cent. This confirms the robustness of similar previously proposed mass estimators. Application to published kinematic data of Milky Way dSphs reveals a tight correlation between enclosed mass and luminosity. Using $N$-body models we show that tidal stripping has little effect on this relation. Comparison against cuspy and cored dark matter haloes extracted from controlled re-simulations of the Aquarius A2 merger tree shows that the high mass densities of ultrafaint galaxies are not compatible with large dark matter cores, and that the (total) halo masses of the classical Milky Way dSphs span a remarkably narrow range ($8 \lesssim \mathrm{log_{10}}\,(M/\mathrm{M_\odot}) \lesssim 10$) at present, showing no clear trend with either galaxy size or luminosity.
DOI：
10.1086/590336
发表时间：
2008-05
期刊：
The Astrophysical Journal
影响因子：
--
作者：
N. Martin;J. D. de Jong;H. Rix
通讯作者：
N. Martin;J. D. de Jong;H. Rix
DOI：
10.3847/1538-4357/aacdfb
发表时间：
2018-04
期刊：
The Astrophysical Journal
影响因子：
--
作者：
J. Simon
通讯作者：
J. Simon