arXiv 2604.166012026-04-17astro-ph.GA

SDSS-V LVM: 验证‘银河系中心’穹顶的性质与位置

SDSS-V LVM: Verifying what, and where, the 'Galactic Center' Lobe is

Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg（海德堡大学天文学计算研究所）；McDonald Observatory, The University of Texas at Austin（德克萨斯大学奥斯汀分校麦克唐纳天文台）；Observatories of the Carnegie Institution for Science（卡内基科学机构天文台）；Departamento de Astronomía, Universidad de Chile（智利大学天文学系）；Universidad Nacional Autónoma de México, Instituto de Astronomía（墨西哥国立自治大学天文学研究所）；Apache Point Observatory and New Mexico State University（新墨西哥州立大学阿帕奇点天文台）；Sternberg Astronomical Institute, Moscow State University（莫斯科国立大学斯登伯格天文研究所）；Department of Physics and Astronomy, University of Utah（犹他大学物理与天文学系）；Universidad Católica del Norte（北天主教学会大学）

K. Kreckel, O. V. Egorov, N. Drory, G. A. Blanc, J. E. Mendez-Delgado, S. Kabanovic, D. Bizyaev, J. R. Brownstein, E. Egorova, J. G. Fernandez-Trincado, P. Garc… 展开作者

K. Kreckel, O. V. Egorov, N. Drory, G. A. Blanc, J. E. Mendez-Delgado, S. Kabanovic, D. Bizyaev, J. R. Brownstein, E. Egorova, J. G. Fernandez-Trincado, P. Garcia, J. D. Gelfand, E. J. Johnston, I. Katkov, J. Kollmeier, F. -H. Liang, K. S. Long, A. Z. Lugo-Aranda, A. Meija, H. -W. Rix, A. Roman-Lopes, C. G. Roman-Zuniga, N. Sattler, S. F. Sanchez, E. Zari, R. de J. Zermeno

备注：: 12 pages, accepted in A&A
发表信息：: A&A 710, A205 (2026)
DOI：: 10.1051/0004-6361/202659505

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AI总结：

通过SDSS-V LVM新观测确认'银河系中心'穹顶为前景电离HII区域，结合离子气体形态、线比和运动学分析，确定其距离约2kpc，并与 Barnard's Loop 提供类比解释。

摘要：

所谓的'银河系中心'穹顶（GCL）是一个位于银河平面以上的扩展（约1度）无线电连续特征，文献中对其性质和位置存在不同说法。利用SDSS-V Local Volume Mapper的新光学积分场光谱观测，我们确认GCL为前景电离HII区域，不与银河中心相关。我们呈现了离子气体形态、线比诊断和运动学的新分析。从受 extinction 影响最小的[SIII]9532发射线图中，我们识别出一个闭合的外环内的电离气体发射，该环并未填充GCL内部。所有光学线比诊断均一致支持电离。通过比较离子气体的Balmer减幅与3D尘埃图，我们直接约束GCL的距离约为2kpc。[NII]6583线运动学显示GCL内有均匀的速度结构，进一步确认整个气泡为一个结构。大小和发射线形态强烈类似于附近Barnard's Loop，提供了一种可能的类比来解释该外壳如何由更远且偏离中心的年轻星团电离。我们建议将GCL缩写重新用于'Greatly Confused Loop'。

英文摘要：

The so-called 'Galactic Center' Lobe (GCL) is an extended (~1 deg) radio continuum feature situated above the Galactic Plane, for which the literature contains varying claims about both its nature and location. Using new optical integral field spectroscopic observations from the SDSS-V Local Volume Mapper, we confirm the characterization of the GCL as a foreground photoionized HII region, not associated with the Galactic center. We present a new analysis of the ionized gas morphology, line ratio diagnostics, and kinematics. From our [SIII]9532 emission line map, which suffers the least extinction, we identify ionized gas emission throughout a closed outer loop, which does not fill the GCL interior. All optical line ratio diagnostics are consistent with photoionization. By comparing the ionized gas reddening from the Balmer decrement with 3D dust maps, we directly constrain the distance to the GCL to ~2 kpc. [NII]6583 line kinematics show a uniform velocity structure across the GCL, further confirming that the entire bubble is one structure. The size and emission line morphology is strongly reminiscent of that seen in the nearby Barnard's Loop, providing a possible analog to explain how this outer shell may be photoionized by a more distant and off-center embedded young cluster. We suggest the acronym GCL be repurposed to instead abbreviate the name 'Greatly Confused Loop'.

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