发表机构
Universidad Complutense de Madrid; European Southern Observatory; Joint ALMA Observatory; RIKEN（马德里康普顿斯大学; 欧洲南方天文台; ALMA联合天文台; 理化学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究银河系中心新发现的G+0.633-0.0604分子云，通过对多种分子谱线分析其物理性质及塑造它的激波，识别出三个速度成分，为研究激波驱动分子复杂性及星团形成提供新实验室。
AI 中文摘要
在中央分子区，激波对触发恒星形成和化学富集起关键作用。Sgr B2复合体是典型例子。本文报道了Sgr B2南部边缘新发现的G+0.633-0.0604云，对其物理性质和激波进行表征。通过多望远镜谱线分析推断气体温度、密度等，识别出三个速度成分，C1可能代表原星团早期阶段。
英文摘要
In the Central Molecular Zone (CMZ), shocks play a key role in triggering star formation and driving chemical enrichment. The Sgr B2 complex is a prime template, hosting massive protoclusters (N, M, S) and the northern G+0.693 cloud, which exhibits shock-induced prestellar signatures. We report on G+0.633-0.0604, a newly identified shock-dominated and chemically rich cloud at the southern edge of Sgr B2, where the next star formation episodes are proposed. We characterise its physical properties and the shocks shaping it. We present analyses on CH$_3$CCH, CH$_3$CN, HC$_3$N, HNCO and several isotopologues of CO to infer the gas $T_{\rm kin}$ and density, using high-sensitivity spectral surveys from the Yebes 40m, IRAM 30m and APEX radio telescopes that covered ~100 GHz across the 31-275 GHz range. We also used 3 mm IRAM 30m mosaics (13'$\times$13') of Sgr B2 in HC$_3$N, HNCO and C$_2$H$_5$OH to probe G+0.633 environment. We identify three velocity components: a narrow main one (C1, $v_{\rm LSR}$~48.5 km/s; FWHM~10 km/s), and two broader, fainter components at higher velocities, C2 (~61 km/s; ~13 km/s) and C3 (~89 km/s; ~18 km/s), all showing similar properties ($T_{\rm kin}$~55-90 K, $N_{\rm H_2}$~(3-7)$\times$10$^{22}$ cm$^{-2}$, $n_{\rm H_2}$~(0.5-2.5)$\times$10$^{4}$ cm$^{-3}$) and extended distributions. C1 delineates G+0.633 physically and coincides with a peak in HNCO, supporting a shock-driven origin likely rooted in the cloud-cloud collision shaping Sgr B2 and also traced by C2, which extends north to G+0.693. C3 is kinematically unlinked and related to large-scale CMZ dynamics. Of the three, C1 may represent a very early protocluster phase, yet to be confirmed. G+0.633 thus emerges as a new shock-dominated CMZ cloud resembling G+0.693, providing another unique laboratory to investigate how shocks drive molecular complexity and regulate the onset of cluster formation in the CMZ.
Comments20 pages, 11 figures, 8 tables, 6 appendix - Accepted for publication in Astronomy & Astrophysics
