论文标题
动态限制银河条的长度
Dynamically constraining the length of the Milky Way bar
论文作者
论文摘要
我们提出了一种使用6D相空间信息来直接整合轨道的新方法来限制银河条的长度。我们根据被困的棒轨道的最大范围为银河棒定义了一个名为$ r_ {freq} $的伪长。我们发现，只有在钢筋的长度和上述电势的长度类似于轨道的初始相位空间坐标的模型时，从轨道测量的$ r_ {freq} $与假定潜力的$ r_ {freq} $一致。因此，可以通过确定哪些假定潜在导致自洽测得的$ r_ {freq} $来测量模型的或银河系的条形长度从6D相位坐标坐标。当我们将此方法应用于Apogee DR17和$ GAIA $ EDR3数据的$ \ $ \ $ \ $ 210,000星时，我们发现仅对于$ \ $ \ $ 3.5 kpc的潜在型号的潜在型号而言，只有一个一致的结果。我们发现银河系的被困的酒吧轨道仅扩展到$ \ $ 3.5 kpc，但是在酒吧末端的恒星末端也延伸到4.8 kpc，这可能与附带的螺旋臂有关。我们还发现，测得的钢筋轨道结构在很大程度上取决于假定电位的性质。
We present a novel method for constraining the length of the Galactic bar using 6D phase space information to directly integrate orbits. We define a pseudo-length for the Galactic bar, named $R_{Freq}$, based on the maximal extent of trapped bar orbits. We find the $R_{Freq}$ measured from orbits is consistent with the $R_{Freq}$ of the assumed potential only when the length of the bar and pattern speed of said potential is similar to the model from which the initial phase-space coordinates of the orbits are derived. Therefore, one can measure the model's or the Milky Way's bar length from 6D phase-space coordinates by determining which assumed potential leads to a self-consistent measured $R_{Freq}$. When we apply this method to $\approx$210,000 stars in APOGEE DR17 and $Gaia$ eDR3 data, we find a consistent result only for potential models with a dynamical bar length of $\approx$3.5 kpc. We find the Milky Way's trapped bar orbits extend out to only $\approx$3.5 kpc, but there is also an overdensity of stars at the end of the bar out to 4.8 kpc which could be related to an attached spiral arm. We also find that the measured orbital structure of the bar is strongly dependent on the properties of the assumed potential.
