High-resolution R~50 000 long-slit spectroscopy of the inner knots of the highly symmetrical protostellar outflow HH 212 was obtained in the 1-0 S(1) line of H2 at 2.12 micron with a spatial resolution of ~0.45 arcsec. At the resulting velocity resolution of ~6 km s-1, multiple slit oriented observations of the northern first knot NK1 clearly show double-peaked line profiles consistent with either a radiative bow shock or dual (forward and reverse) shocks. In contrast, the velocity distribution of the southern first knot SK1 remains single-peaked, suggesting a significantly lower jet velocity and possibly a different density variation in the jet pulses in the southern flow compared to the northern flow. Comparison with a semi-empirical analytical model of bow shock emission allows us to constrain parameters such as the bow inclination to the line of sight, the bow shock and jet velocities for each flow. Although a few features are not reproduced by this model, it confirms the presence of several dynamical and kinematical asymmetries between opposite sides of the HH 212 bipolar jet. The position-velocity diagrams of both knots exhibit complex dynamics that are broadly consistent with emission from a bow shock and/or jet shock, which does not exclude jet rotation, although a clear signature of jet rotation in HH 212 is missing. Alternative interpretations of the variation of radial velocity across these knots, such as a variation in the jet orientation, as well as for the velocity asymmetries between the flows, are also considered. The presence of a correlation between flow velocity and collimation in each flow is suggested.
Optical and Infrared Imaging and Spectroscopy of the Multiple-Shell Planetary Nebula NGC 6369
NGC 6369是一个双壳层行星状星云(PN),由明亮的环形内壳层和暗淡的双极扩展层组成。我们已经使用地面和空间的窄带光学和近红外图像,宽带中红外图像,光学长缝阶梯光谱,和中红外光谱来研究它的物理结构。这些观测结果表明,NGC 6369的内壳可以被描述为一个类似于桶的结构形状与极性泡状突起,并揭示了H2和强多环芳烃(PAHs)的光离解区(PDR)的证据位于明亮的内壳外的分子夹杂物。高分辨率的哈勃望远镜窄带图像揭示了一个复杂的激发结构的内壳和一个系统的“彗星”结。NGC 6369的包层看起来很棘手,缺乏壳层膨胀的运动学证据,PDR外电离物质的发射明显存在,这些都使我们认为NGC 6369的包层不是一个真正的壳层,而是赤道区域的一个扁平结构。我们报告了在低激发和分子线发射中发现的不规则的结和斑点的扩散发射,这些发射位于距离中心恒星80”的地方,在主星云壳层之外。我们还表明,与极性突起相关联的细丝具有与冲击后冷却制度相一致的空间范围,并且可能代表这些结构与周围材料相互作用的区域。
Particle Acceleration and Depolarization in the Protostellar jet knots HH 80 and HH 81
Indian Institute of Space Science and Technology(印度空间科学与技术学院);Indian Institute of Science(印度科学学院);New Mexico Institute of Mining and Technology(新墨西哥矿业与技术学院);Instituto de Radiastronomía y Astrofísica (IRyA) Universidad Nacional Autónoma de México (UNAM)(墨西哥国立自治大学射电天文学与天体物理研究所);Instituto de Astronomía Teórica y Experimental (IATE) Universidad Nacional de Córdoba (UNC)(科尔多瓦国立大学理论与实验天体物理研究所)
The Structure and Kinematics of Three Class 0 Protostellar Jets from JWST
Ritter Astrophysical Research Center, Dept. of Physics and Astronomy, University of Toledo(托莱多大学物理与天文学系里特天文研究中心);INAF-Osservatorio Astronomico di Capodimonte(意大利国家天体物理研究所卡波迪蒙特天文台);Jet Propulsion Laboratory, California Institute of Technology(加州理工学院喷气推进实验室);Tata Institute of Fundamental Research(塔塔基础研究所);Department of Astronomy, The University of Texas at Austin(德克萨斯大学奥斯汀分校天文学系);Dipartimento di Fisica, Università degli Studi di Milano(米兰大学物理系);Leiden Observatory, Leiden University(莱顿大学莱顿天文台);Max Planck Institute for Astronomy(马克斯·普朗克天文学研究所);Departamento de Astronomía, Universidad de Concepción(康塞普西翁大学天文学系)
Axisymmetric Modeling of DSHARP Dusty Disks: Asymmetric Structures and Inner-Disk Dispersal
College of Science, Ibaraki University(茨城大学理学部);Tsung-Dao Lee Institute, Shanghai Jiao Tong University(上海交通大学李政道研究所);RIKEN Cluster for Pioneering Research(理化学院先锋研究集群);Division of Liberal Arts, Kogakuin University(工学院大学人文学部);National Astronomical Observatory of Japan(日本国立天文台)