تقرير
Widespread subsonic turbulence in Ophiuchus North 1
العنوان: | Widespread subsonic turbulence in Ophiuchus North 1 |
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المؤلفون: | Gong, Yan, Liu, Shu, Wang, Junzhi, Zhu, Weishan, Li, Guang-Xing, Yang, Wenjin, Sun, Jixian |
المصدر: | A&A 663, A82 (2022) |
سنة النشر: | 2022 |
مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies |
الوصف: | Supersonic motions are common in molecular clouds. (Sub)sonic turbulence is usually detected toward dense cores and filaments. However, it remains unknown whether (sub)sonic motions at larger scales ($\gtrsim$1~pc) can be present in different environments or not. Located at a distance of about 110 pc, Ophiuchus North 1 (Oph N1) is one of the nearest molecular clouds that allows in-depth investigation of its turbulence properties by large-scale mapping observations of single-dish telescopes. We carried out the $^{12}$CO ($J=1-0$) and C$^{18}$O ($J=1-0$) imaging observations toward Oph N1 with the Purple Mountain Observatory 13.7 m telescope. The observations have an angular resolution of $\sim$55\arcsec (i.e., 0.03~pc). Most of the whole C$^{18}$O emitting regions have Mach numbers of $\lesssim$1, demonstrating the large-scale (sub)sonic turbulence across Oph N1. Based on the polarization measurements, we estimate the magnetic field strength of the plane-of-sky component to be $\gtrsim$9~$\mu$G. We infer that Oph N1 is globally sub-Alfv{\'e}nic, and is supported against gravity mainly by the magnetic field. The steep velocity structure function can be caused by the expansion of the Sh~2-27 H{\scriptsize II} region or the dissipative range of incompressible turbulence. Our observations reveal a surprising case of clouds characterised by widespread subsonic turbulence and steep size-linewidth relationship. This cloud is magnetized where ion-neutral friction should play an important role. Comment: 16 pages, 12 figures, accepted for publication in A&A |
نوع الوثيقة: | Working Paper |
DOI: | 10.1051/0004-6361/202142713 |
URL الوصول: | http://arxiv.org/abs/2203.14989 |
رقم الأكسشن: | edsarx.2203.14989 |
قاعدة البيانات: | arXiv |
DOI: | 10.1051/0004-6361/202142713 |
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