论文标题
L1521 F的恒星形成过程中的扭曲磁场,使用James Clerk Maxwell望远镜亚毫米二重带极化表揭示
Twisted magnetic field in star formation processes of L1521 F revealed by submillimeter dual band polarimetry using James Clerk Maxwell Telescope
论文作者
论文摘要
了解恒星形成的初始条件需要考虑磁场的观察性研究和理论工作,这在恒星形成过程中起着重要作用。在此,我们在金牛座分子云中研究了附近的年轻云核L1521 f($ n $(h $ _2 $)$ \ sim 10^{4-6} $ cm $^{ - 3} $)。该密集的核心托有一个0.2 $ m_ \ odot $ Protostar,被归类为具有复杂速度结构的非常低的光度对象,尤其是在Protostar的附近。为了追踪密集芯内的磁场,我们使用位于Scuba-2亚略微计算机相机前的POL-2偏光仪在James Clerk Maxwell TeteScope上的POL-2极光计,对$λ$ = 850 $ $ m $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ = 850 $ $ m,进行了高灵敏度的磁力光计。将其与Alma的$λ$ = 3.3毫米所采用的毫米偏振法进行了比较。磁场以$λ$ = 850 $μ$ m的位置检测到外围区域,该区域朝北方向螺纹,而中央区域则以$λ$ = 450 $μ$ M的追溯,显示了一个具有东西方向的磁场,即与外围区域的正交相关。磁场强度估计是$ \ sim $ 70 $ $ g和200 $ $ g $ g和200 $ $ g,分别使用davis-chandrasekhar-fermi方法,分别在外围和中央区域。对于两个区域而言,所得的质量频率比大于磁性临界状态的质量比率大3倍,这表明L1521 F是磁性超临界的,即引力力在磁性湍流力上占主导地位。将观测数据与MHD模拟相结合,首次得出了该令人困惑对象的形态学特性的详细参数。
Understanding the initial conditions of star formation requires both observational studies and theoretical works taking into account the magnetic field, which plays an important role in star formation processes. Herein, we study the young nearby dense cloud core L1521 F ($n$(H$_2$) $\sim 10^{4-6}$ cm$^{-3}$) in the Taurus Molecular Cloud. This dense core hosts a 0.2 $M_\odot$ protostar, categorized as a Very Low Luminosity Objects with complex velocity structures, particularly in the vicinity of the protostar. To trace the magnetic field within the dense core, we conducted high sensitivity submillimeter polarimetry of the dust continuum at $λ$= 850 $μ$m and 450 $μ$m using the POL-2 polarimeter situated in front of the SCUBA-2 submillimeter bolometer camera on James Clerk Maxwell Tetescope. This was compared with millimeter polarimetry taken at $λ$= 3.3 mm with ALMA. The magnetic field was detected at $λ$= 850 $μ$m in the peripheral region, which is threaded in a north-south direction, while the central region traced at $λ$= 450 $μ$m shows a magnetic field with an east-west direction, i.e., orthogonal to that of the peripheral region. Magnetic field strengths are estimated to be $\sim$70 $μ$G and 200 $μ$G in the peripheral- and central-regions, respectively, using the Davis-Chandrasekhar-Fermi method. The resulting mass-to-flux ratio of 3 times larger than that of magnetically critical state for both regions indicates that L1521 F is magnetically supercritical, i.e., gravitational forces dominate over magnetic turbulence forces. Combining observational data with MHD simulations, detailed parameters of the morphological properties of this puzzling object are derived for the first time.