论文标题
校准BHB星星距离尺度和距银河中心的光环运动距离
Calibrating the BHB Star Distance Scale and the Halo Kinematic Distance to the Galactic Centre
论文作者
论文摘要
我们报告了基于光环对象的运动学的首次确定到银河中心的距离。我们将统计 - 帕拉克斯技术应用于Xue等人编译的〜2500蓝色水平分支（BHB）星的样品。 （2011）同时将校正因子限制为BHB星的光度距离，并由这些作者报道，到达银河中心的距离找到R0 = 8.2 +/- 0.6 kpc。我们还发现，BHB恒星样品在银河旋转方向上的平均速度，V0 = -240 +/- 4 km/s，绝对值的平均速度比晕光的速度（v0 = -222222222 +/- 4 km/s）在半间隔中的halo rr llyae型恒星的绝对值大约20 km/s，从6 kp的速度（v0 = -222 +/- 4 km/s）k. v）和径向（Sigma R）BHB样品的速度分散率比Halo RR Lyrae类型变量的速度分散椭圆形的相应参数小约40-45 km/s。光晕BHB星的速度色散张量与RR Lyrae类型变量的相应张量相比，其各向异性明显少：相应的各向异性参数值等于beta（BHB）= 0.51 +//- 0.02和BetA（RR）= 0.71 +/-01 = 0.71 +/- 0.03。
We report the first determination of the distance to the Galactic centre based on the kinematics of halo objects. We apply the statistical-parallax technique to the sample of ~2500 Blue Horizontal Branch (BHB) stars compiled by Xue et al. (2011) to simultaneously constrain the correction factor to the photometric distances of BHB stars as reported by those authors and the distance to the Galactic centre to find R0=8.2+/-0.6 kpc. We also find that the average velocity of our BHB star sample in the direction of Galactic rotation, V0=-240+/-4 km/s, is greater by about 20 km/s in absolute value than the corresponding velocity for halo RR Lyrae type stars (V0=-222+/-4 km/s) in the Galactocentric distance interval from 6 to 18 kpc, whereas the total (sigma V) and radial (sigma r) velocity dispersion of the of the BHB sample are smaller by about 40-45 km/s than the corresponding parameters of the velocity dispersion ellipsoid of halo RR Lyrae type variables. The velocity dispersion tensor of halo BHB stars proved to be markedly less anisotropic than the corresponding tensor for RR Lyrae type variables: the corresponding anisotropy parameter values are equal to beta(BHB)=0.51+/-0.02 and beta(RR)=0.71+/-0.03, respectively.
