JCMT POL-2 and BISTRO Survey Observations of Magnetic Fields in the L1689 Molecular Cloud-猫眼课题宝

DOI：

10.3847/1538-4357/abcc6c

发表时间：

2020-11

期刊：

The Astrophysical Journal

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

K. Pattle;S. Lai;J. Francesco;S. Sadavoy;D. Ward-Thompson;D. Johnstone;Thiem C. Hoang;D. Arzoumanian;P. Bastien;T. Bourke;S. Coud'e;Y. Doi;C. Eswaraiah;L. Fanciullo;R. Furuya;J. Hwang;C. Hull;Ji-hyun Kang;Kee-Tae Kim;F. Kirchschlager;J. Kwon;W. Kwon;C. Lee;Tie Liu;M. Redman;A. Soam;M. Tahani;M. Tamura;Xindi Tang

我们用詹姆斯·克拉克麦克斯韦望远镜（JCMT）上的POL-2偏振仪对附近蛇夫座分子云复合体的一部分L1689分子云进行了850 μm偏振观测。我们观测到L1689的三个区域：包含IRAS 16293-2433原恒星系统的L1689 N团，无星的SMM-16团和无星的核心L1689 B。我们使用Davis-Prasekhar-Fermi方法估计L1689 N的天平面场强为366 ± 55 μG，SMM-16为284 ± 34 μG，L1689 B为72 ± 33 μG，作为我们的尘埃不透明度基准值。这些值表明，所有这三个地区可能是磁跨临界亚阿尔夫文湍流。在这三个区域中，推断出的平均磁场方向近似垂直于赫歇尔太空望远镜观测中确定的当地灯丝方向。L1689 N和L1689 B的核心尺度场形态与普朗克空间天文台测量的云尺度场形态一致，表明这些源的物质可以从大尺度自由流动到小尺度。基于这些磁场测量，我们认为，从云到L1689 N和L1689 B的吸积可能是磁调节的。然而，在SMM-16中，团尺度场几乎垂直于普朗克在云尺度上看到的场，这表明它可能无法有效地从周围吸积更多的物质。

We present 850 μm polarization observations of the L1689 molecular cloud, part of the nearby Ophiuchus molecular cloud complex, taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope (JCMT). We observe three regions of L1689: the clump L1689N which houses the IRAS 16293-2433 protostellar system, the starless clump SMM-16, and the starless core L1689B. We use the Davis–Chandrasekhar–Fermi method to estimate plane-of-sky field strengths of 366 ± 55 μG in L1689N, 284 ± 34 μG in SMM-16, and 72 ± 33 μG in L1689B, for our fiducial value of dust opacity. These values indicate that all three regions are likely to be magnetically transcritical with sub-Alfvénic turbulence. In all three regions, the inferred mean magnetic field direction is approximately perpendicular to the local filament direction identified in Herschel Space Telescope observations. The core-scale field morphologies for L1689N and L1689B are consistent with the cloud-scale field morphology measured by the Planck Space Observatory, suggesting that material can flow freely from large to small scales for these sources. Based on these magnetic field measurements, we posit that accretion from the cloud onto L1689N and L1689B may be magnetically regulated. However, in SMM-16, the clump-scale field is nearly perpendicular to the field seen on cloud scales by Planck, suggesting that it may be unable to efficiently accrete further material from its surroundings.

JCMT POL-2 and BISTRO Survey Observations of Magnetic Fields in the L1689 Molecular Cloud

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