标题： NGC 1700中的三维质量分布 显示英文标题

标题： The Three-Dimensional Mass Distribution in NGC 1700

摘要： 使用来自文献的表面光电测量和最近获得的高精度恒星动力学数据的各种建模技术，来限制发光尖椭圆星系NGC 1700中的三维质量分布。 首先，我们对径向速度场和光电测量进行建模，并利用贝叶斯方法估计五个同心环带内的三轴性T和短轴与长轴之比c，这些环带大致位于1到3个有效半径之间。 结果完全一致表明T在大约2.5倍r_e（36弧秒；6.7/h千秒差距）以内是常数。 如果将T作为先验信息假设为常数，则可以得到一个上限T<0.16（95%置信度）；如果进一步假设角动量与星系固有短轴完全对齐，则这一上限放松至T<0.22。 近似轴对称允许我们随后使用轴对称模型来限制径向质量分布。 使用Jeans（矩）方程，我们证明了2积分、恒定M/L模型无法拟合数据；但一个2积分模型，在其中从中心向外到12/h千秒差距范围内累积的M/L增加了大约一倍，是可以的。 通过二次规划构建的各向异性3积分模型显示，实际上没有恒定M/L模型能与动力学数据一致。 具有可变M/L的各向异性3积分模型虽然不能唯一确定最小可接受的晕质量，但像矩模型一样，在12/h千秒差距处累积的M/L_B大约为10h。 我们得出结论，NGC 1700代表了迄今为止椭圆星系中暗物质的最佳恒星动力学证据。 显示英文摘要

摘要： A variety of modeling techniques is used with surface photometry from the literature and recently acquired high-accuracy stellar kinematic data to constrain the three-dimensional mass distribution in the luminous cuspy elliptical galaxy NGC 1700. First, we model the radial velocity field and photometry, and, using a Bayesian technique, estimate the triaxiality T and short-to-long axis ratio c in five concentric annuli between approximately 1 and 3 effective radii. The results are completely consistent with T being constant inside about 2.5 r_e (36 arcsec; 6.7/h kpc). Adding an assumption of constant T as prior information gives an upper limit of T < 0.16 (95% confidence); this relaxes to T < 0.22 if it is also assumed that there is perfect alignment between the angular momentum and the galaxy's intrinsic short axis. Near axisymmetry permits us then to use axisymmetric models to constrain the radial mass profile. Using the Jeans (moment) equations, we demonstrate that 2-integral, constant-M/L models cannot fit the data; but a 2-integral model in which the cumulative enclosed M/L increases by a factor of roughly 2 from the center out to 12/h kpc can. Three-integral models constructed by quadratic programming show that, in fact, no constant-M/L model is consistent with the kinematics. Anisotropic 3-integral models with variable M/L, while not uniquely establishing a minimum acceptable halo mass, imply, as do the moment models, a cumulative M/L_B approximately 10 h at 12/h kpc. We conclude that NGC 1700 represents the best stellar dynamical evidence to date for dark matter in elliptical galaxies.