Does HL Tau disc polarization in ALMA band 3 come from radiatively aligned grains?
Does HL Tau disc polarization in ALMA band 3 come from radiatively aligned grains?
复制标题
ALMA 带 3 中的 HL Tau 圆盘极化是否来自辐射排列的颗粒？
DOI：
10.1093/mnras/sty3263
复制
发表时间：
2018
影响因子：
4.8
通讯作者：
Looney, Leslie
中科院分区：
文献类型：
--
作者：
Yang, Haifeng;Li, Zhi-Yun;Stephens, Ian W;Kataoka, Akimasa;Looney, Leslie
在阿塔卡玛大型毫米/亚毫米阵列（阿尔马）时代，（亚）毫米尘埃连续谱中的圆盘偏振是一个快速发展的领域。它开辟了令人兴奋的可能性，检测和表征磁场和晶粒生长的光盘周围的年轻恒星物体。然而，使用偏振探测光盘的属性，其生产机制必须首先确定。到目前为止，传统的机制，包括磁性排列的晶粒未能解释在大多数光盘检测到的偏振模式。这对于阿尔马波段3（波长为3mm）中HL Tau的倾斜盘尤其如此，其具有椭圆偏振图案。椭圆图案被认为是尘埃颗粒偏振发射的证据，其长轴垂直于辐射通量的方向。我们发现，即使在倾斜的光盘，如HL头的辐射对齐的晶粒产生一个圆形，而不是椭圆形，偏振模式。椭圆偏振模式可以产生，如果晶粒排列空气动力学之间的差异，在旋转速度的尘埃和气体通过黄金机制。然而，一个强大的方位角变化的偏振强度预期的辐射和空气动力学的路线，但没有观察到在HL Tau盘在阿尔马带3。我们的结论是，这两种机制都不能单独解释的数据和起源的3毫米偏振仍然是一个谜。我们推测，这个谜可能是解决的直接排放和散射的空气动力学排列的颗粒相结合。
Disc polarization in (sub)millimeter dust continuum is a rapidly growing field in the Atacama Large Millimeter/submillimeter Array (ALMA) era. It opens up the exciting possibility of detecting and characterizing magnetic fields and grain growth in discs around young stellar objects. However, to use polarization for probing the disc properties, its production mechanism must be ascertained first. To date, the conventional mechanism involving magnetically aligned grains fails to explain the polarization patterns detected in most discs. This is especially true for the inclined disc of HL Tau in ALMA Band 3 (wavelength ∼3 mm), which has an elliptical polarization pattern. The elliptical pattern was taken as evidence for polarized emission by dust grains aligned with their long axes perpendicular to the direction of the radiative flux. We show that the radiatively aligned grains produce a circular, rather than elliptical, polarization pattern even in inclined discs such as HL Tau. An elliptical polarization pattern can be produced if the grains are aligned aerodynamically by the difference in rotation speed between the dust and the gas through the Gold mechanism. However, a strong azimuthal variation in polarized intensity is expected for both the radiative and aerodynamic alignments, but not observed in the HL Tau disc in ALMA Band 3. We conclude that neither of these two mechanisms alone can explain the data and the origin of the 3 mm polarization remains a mystery. We speculate that this mystery may be resolved by a combination of both direct emission and scattering by aerodynamically aligned grains.
登录
查看更多内容
DOI：
--
发表时间：
1967
期刊：
影响因子：
--
作者：
R. V. Jones;L. Spitzer
通讯作者：
L. Spitzer
两个年轻的边缘原恒星盘的 ALMA 尘埃偏振观测
DOI：
10.3847/1538-4357/aaa769
发表时间：
2018
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Lee, Chin-Fei;Li, Zhi-Yun;Ching, Tao-Chung;Lai, Shih-Ping;Yang, Haifeng
通讯作者：
Yang, Haifeng
ALMA 对英仙座分子云中 10 颗原恒星的偏振视图
DOI：
10.3847/1538-4357/aaacd2
发表时间：
2018
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Cox, Erin G.;Harris, Robert J.;Looney, Leslie W.;Li, Zhi-Yun;Yang, Haifeng;J. Tobin, John;Stephens, Ian
通讯作者：
Stephens, Ian
通过机械扭矩对齐不规则颗粒
DOI：
10.3847/1538-4357/aa9edc
发表时间：
2018
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Hoang, Thiem;Cho, Jungyeon;Lazarian, A.
通讯作者：
Lazarian, A.
年轻的环双星盘中的磁场
影响因子：
6.5
作者：
Felipe O. Alves;J. Girart;M. Padovani;Daniele Galli;Gabriel A. P. Franco;Paola Caselli;W. Vlemmings;Qizhou Zhang;H. Wiesemeyer
通讯作者：
H. Wiesemeyer