Dark matter in elliptical galaxies – I. Is the total mass density profile of the NFW form or even steeper?
Dark matter in elliptical galaxies – I. Is the total mass density profile of the NFW form or even steeper?
复制标题
椭圆星系中的暗物质 – I. NFW 形式的总质量密度分布是否更陡峭？
DOI：
10.1111/j.1365-2966.2005.09225.x
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发表时间：
2004
影响因子：
4.8
通讯作者：
Poland
中科院分区：
文献类型：
--
作者：
G. Mamon;E. L. L. Iap;París;France.;Camk;Warsaw;Poland
在无耗散的CDM N体模拟中，椭圆星系被模拟为具有密度分布(DPS)的椭圆星系，其总质量来自于晕的DPS。事实证明，椭圆线与代表总质量的尖尖低浓度NFW模型不一致，与更陡峭的1.5内斜率不一致，也与Navarro等人提出的较浅的模型不一致。根据几次X射线观测推断，NFW模型的密度也不是预测的10倍：向内外推的质量模型导致局部质光比小于有效半径(Re)内的恒星值，并导致中心孔径速度色散小于观测。只要暗物质(DM)DPS在0.01维里半径内没有急剧变陡(斜率<；2)，这一结论仍然成立。由类似NFW的总质量剖面在Re内产生的太小的总质量和速度色散表明，恒星分量应该使Dm 1至少达到Re。然后，应该很难从运动学上约束椭圆暗物质Dp的内侧斜率。从X射线观测得到的高浓度参数似乎是将NFW模型与主宰内部的恒星分量和主宰外部的Dm分量的总质量Dp相匹配的结果。附录给出了纳瓦罗等人的浓度参数、中心密度和总质量与维里质量的关系。模特。在第二个附录中，给出了沿视线、圆孔和狭缝中平均的速度色散的单一积分表达式，以及具有各向同性轨道的一般光度密度和质量分布。
Elliptical galaxies are modelled as Sersic luminosity dis tributions with density profiles (DPs) for the total mass adopted from the DPs of haloes within dissipationlessCDM N- body simulations. Ellipticals turn out to be inconsistent w ith cuspy low-concentration NFW models representing the total mass, nor are they consistent with a steeper 1.5 inner slope, nor with the shallower models proposed by Navarro et al. (2004), nor with NFW models 10 times more concentrated than predicted, as deduced from several X-ray observations: the mass models, extrapolated inwards, lead to local mass-to-light ratios that are smaller than the stellar value inside an effective radius (Re), and to central aperture velocity dispersions that are muc h smaller than observed. This conclusion remains true as long as there is no sharp steepening (slope < 2) of the dark matter (DM) DPs just inside 0.01 virial radii. The too low total mass and velocity dispersion produced within Re by an NFW-like total mass profile suggests that the stellar component should domi nate the DM one out to at least Re. It should then be difficult to kinematically constrain the i nner slope of the dark matter DP of ellipticals. The high concentration parameters deduced from X-ray observations appear to be a consequence of fitting an NFW model to the total mass DP m ade up of a stellar component that dominates inside and a DM component that dominates outwards. An appendix gives the virial mass dependence of the concentration parameter, central density, and total mass of the Navarro et al. model. In a 2nd appendix are given single integral expressions for the velocity dispersions averaged along the line-of-sight, in circular apertures and in thin slits, for general luminosity density and mass di stributions, with isotropic orbits.