论文标题
极化，极化效率和谷物对准簇NGC 2345
Polarization, Polarizing Efficiency, and Grain alignment towards the direction of the cluster NGC 2345
论文作者
论文摘要
我们使用多波段光学偏光观测值研究了谷物对齐和灰尘特性朝向NGC 2345的方向。对于大多数恒星，发现观察到的极化是由于星际培养基的最大值和波长的平均值分别为1.55％和0.58 $μm$。这揭示了灰尘晶粒的尺寸分布与NGC 2345方向上的一般星际介质中的尺寸分布相似。在NGC 2345的方向上，已经注意到了1.2 kpc距离NGC 2345方向的灰尘特性的改变。发现位于此距离之外的尘埃颗粒与银河磁场对齐，而在该距离前景中的灰尘晶粒方向分散。发现晶粒在这个方向上的偏振效率接近我们银河系的平均效率。晶粒尺寸减小以及对簇的核心区域的偏振效率的提高表明，在集群中，局部辐射场较高，这导致小晶粒的比对效率提高。还发现最大极化的波长（与对齐晶粒的平均大小相关）随着灭绝的灭绝和减小而随着偏振效率的提高而增加，这可以通过辐射扭矩比对机制来解释。
We have investigated the grain alignment and dust properties towards the direction of the cluster NGC 2345 using the multi-band optical polarimetric observations. For the majority of the stars, the observed polarization is found to be due to the interstellar medium with average values of maximum polarization and wavelength corresponding to it as 1.55% and 0.58 $μm$, respectively. This reveals a similar size distribution of dust grains to that in the general interstellar medium in the direction of NGC 2345. Alteration of dust properties near the distance of 1.2 kpc towards the direction of NGC 2345 has been noticed. The dust grains located beyond this distance are found to be aligned with the Galactic magnetic field, whereas a dispersion in orientation of the dust grains lying in the foreground of this distance is found. Polarizing efficiency of grains in this direction is found to be close to the average efficiency for our Galaxy. The decreased grain size along with the increased polarizing efficiency towards the core region of the cluster indicates the local radiation field is higher within the cluster which is responsible for the increased alignment efficiency of small grains. The wavelength of maximum polarization (associated with the average size of aligned grains) is also found to increase with extinction and reduces with the increase in polarizing efficiency, which can be explained by the radiative torque alignment mechanism.
