发表机构
Sternberg Astronomical Institute, Lomonosov Moscow State University; Lomonosov Moscow State University, Faculty of Physics（列昂尼德·莫索科夫国立莫斯科大学斯腾伯格天体物理研究所; 列昂尼德·莫索科夫国立莫斯科大学物理系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究基于Gaia DR3数据，利用运动学模型分析2384个年轻疏散星团，确定银河系旋转曲线及速度场参数，发现太阳处旋转速度242.3 km/s，并给出旋臂螺距角等参数。
AI 中文摘要
我们采用一个包含银盘圆周旋转的运动学模型，并纳入由旋涡密度波产生的效应，该模型具有恒定的径向和垂直速度弥散张量分量，并采用太阳到银心距离R_0=8.277kpc（由GRAVITY合作组于2022年推断），来推导来自Hunt和Reffert（2024）星表中2384个年龄不超过100 Myr的疏散星团样本的速度场参数，这些星团几乎全部位于银道距离5至14 kpc之间。我们使用最大似然法和Goodman和Weare（2010）提出的仿射不变马尔可夫链蒙特卡洛方法估计速度场参数，两种方法得出的参数值几乎相同。推断出的旋转曲线总体上与基于银河系脉泽样本的运动学分析结果一致。我们发现太阳距离处的线性旋转速度为V=242.3±1.1 km/s；在银道距离约R_g~7 kpc处达到最大值V~244 km/s，随后缓慢平滑下降，在R_g=14 kpc处V~227 km/s。推断的速度弥散张量的径向和垂直分量分别为(σU_0, σW_0)~(10.63±0.15, 4.56±0.15) km/s。对于四臂旋涡结构，我们发现螺距角和太阳相位分别为i~-11.7±0.3度和χ_0~138±5度，径向和切向扰动的振幅分别为f_R=-3.0±0.4和f_θ=-3.1±0.4 km/s。
英文摘要
We use a kinematical model including circular rotation of the Milky-Way disk incorporating effects produced by a spiral density wave with constant radial and vertical components of the velocity dispersion tensor and adopted solar Galactocentric distance R_0=8.277kpc (inferred by GRAVITY collaboration in 2022) to derive the velocity field parameters for a sample of 2384 open clusters from the Hunt and Reffert (2024) catalog having ages no greater than 100 Myr almost all of which reside at Galactoaxial distances between 5 and 14 kpc. We estimate the velocity-field parameters using maximum-likelyhood method and the affine-invariant variant of the Markov chain Monte-Carlo method proposed by Goodman and Weare (2010) with both methods yieilding almost identical parameter values. The inferred rotation curve, on the whole, is consistent with the results based on our kinematical analysis of a sample of Galactic masers. We find the linear rotation velocity at the solar distance to be V=242.3+/-1.1~km/s; it reaches its maximum V~244 km/s at Galactoaxial distance of about R_g~7 kpc followed by a slow and smooth decline with V~227 km/s at R_g=14 kpc. The inferred radial and vertical components of the velocity dispersion tensor are (sigma U_0, sigma W_0)~(10.63+/-0.15, 4.56+/-0.15) km/s. We find the pitch angle and the phase of the Sun for a four-armed spiral pattern to be i~-11.7+/-0.3 degrees and chi_0~138+/-5 degrees, respectively, and the amplitudes of radial and tangential perturbations, f_R=-3.0+/-0.4 and f_{theta}=-3.1+/-0.4 km/s, respectively.
Comments11 pages, 6 figures, Accepted to Astrophysical Bulletin
