论文标题
玫瑰花星云和NGC 2244的恒星种群：概率随机森林的应用
Stellar population of the Rosette Nebula and NGC 2244: application of the probabilistic random forest
论文作者
论文摘要
（删节）在这项工作中，我们研究了以年轻的NGC NGC 2244为中心的象征性玫瑰花ne的2.8x2.6 deg2区域，目的是构建迄今为止最可靠的候选成员列表，确定各种结构性和运动学参数，并了解该地区的过去和未来。从包含光学到中印刷光度法的目录以及Gaia EDR3的位置和适当运动开始，我们应用了概率随机森林算法，并为每个源提供了成员概率。 Based on the list of almost 3000 probable members, of which about a third are concentrated within the radius of 20' from the centre of NGC 2244, we identify various clustered sources and stellar concentrations, and estimate the average distance of 1489+-37 pc (entire region), 1440+-32 pc (NGC 2244) and 1525+-36 pc (NGC 2237).质量，灭绝和年龄是通过SED拟合得出的，并且相对于NGC 2244的平均正确运动，通过适当的运动来评估内部动力学。NGC2244显示出明显的膨胀模式，其膨胀速度随半径增加而增加。它的IMF由两种功率定律（DN/DM \ Propto m^{ - α}）很好地表示，质量范围为0.2-1.5 msun的斜率α= 1.05+-0.02，质量范围为1.5-20 msun，与其他星形区域一致。该地区的平均年龄为〜2 Myr。我们发现证据表明NGC 2244与与分子云相关的区域之间的年龄差异，这似乎略年轻。 NGC 2244的速度分散率远高于源自总质量（1000+-70 msun）和半质量半径（3.4+-0.2 PC）的病毒速度分散体。从比较到其他簇和数值模拟，我们得出结论，NGC 2244可能是未结合的，甚至可能在超级病毒状态下形成。
(Abridged) In this work, we study the 2.8x2.6 deg2 region in the emblematic Rosette Nebula, centred at the young cluster NGC 2244, with the aim of constructing the most reliable candidate member list to date, determining various structural and kinematic parameters, and learning about the past and the future of the region. Starting from a catalogue containing optical to mid-infrared photometry, as well as positions and proper motions from Gaia EDR3, we apply the Probabilistic Random Forest algorithm and derive membership probability for each source. Based on the list of almost 3000 probable members, of which about a third are concentrated within the radius of 20' from the centre of NGC 2244, we identify various clustered sources and stellar concentrations, and estimate the average distance of 1489+-37 pc (entire region), 1440+-32 pc (NGC 2244) and 1525+-36 pc (NGC 2237). The masses, extinction, and ages are derived by SED fitting, and the internal dynamic is assessed via proper motions relative to the mean proper motion of NGC 2244. NGC 2244 is showing a clear expansion pattern, with an expansion velocity that increases with radius. Its IMF is well represented by two power laws (dN/dM\propto M^{-α}), with slopes α= 1.05+-0.02 for the mass range 0.2 - 1.5 MSun, and α= 2.3+-0.3 for the mass range 1.5 - 20 MSun, in agreement with other star forming regions. The mean age of the region is ~2 Myr. We find evidence for the difference in ages between NGC 2244 and the region associated with the molecular cloud, which appears slightly younger. The velocity dispersion of NGC 2244 is well above the virial velocity dispersion derived from the total mass (1000+-70 MSun) and half-mass radius (3.4+-0.2 pc). From the comparison to other clusters and to numerical simulations, we conclude that NGC 2244 may be unbound, and possibly even formed in a super-virial state.
