AI 中文总结
该研究用17年Fermi-LAT数据在银南天区识别出与南部eROSITA气泡对应的大规模弥散伽马射线结构，其光谱特性支持轻子逆康普顿起源场景。
AI 中文摘要
我们利用17年的Fermi-LAT数据，识别并表征了银南天区的一个大规模弥散伽马射线结构。能量相关似然分析纳入了多种替代银河弥散发射模型、各向同性发射、费米气泡以及已分辨的4FGL源，结果显示存在一个延伸的 excess（超出预期信号），该信号在所有测试的背景模型中均持续存在，且跨度达数十度。该 excess 大致遵循X射线定义的南部eROSITA气泡（eB）区域，同时也与Loop I的投影南部延伸部分重叠。模板拟合结果支持采用类eB的填充形态，而非已采用的Wolleben Loop I壳层几何结构，这使得该结构成为南部eB的合理伽马射线对应体，尽管无法排除与Loop I相关或其他局域前景发射的可能性。在eB模板下，南部成分比北部大规模成分更暗、更软，积分光度低约7倍，这与eROSITA气泡的不对称性大致相符。若将其解释为银河尺度外流发射，其微弱、偏软的能谱可能表明粒子已老化和/或气泡外层存在分布式再加速。强子起源解释在能量上要求较高，而轻子逆康普顿场景更具经济性，但需要高能电子的快速传输和/或局域再加速。
英文摘要
We identify and characterize a large-scale diffuse gamma-ray structure in the Southern Galactic Hemisphere using 17 yr of Fermi-LAT data. An energy-dependent likelihood analysis, including alternative Galactic diffuse-emission models, isotropic emission, the Fermi bubbles, and resolved 4FGL sources, reveals an extended excess that persists across the tested background models and spans tens of degrees. The excess broadly follows the X-ray-defined southern eROSITA Bubble (eB) region, while also overlapping the projected southern extension of Loop I. Template fits favor a filled eB-like morphology over the adopted Wolleben Loop I shell geometry, making the structure a plausible gamma-ray counterpart of the southern eB, although Loop-I-related or other localized foreground emission cannot be excluded. Under the eB template, the southern component is fainter and softer than the northern large-scale component, with an integrated luminosity lower by a factor of about seven, broadly consistent with the eROSITA-bubble asymmetry. If interpreted as Galactic-scale outflow emission, its faint, soft spectrum may indicate aged particles and/or distributed reacceleration in the outer bubble. A hadronic interpretation is energetically demanding, whereas a leptonic inverse-Compton scenario is more economical but requires rapid transport and/or local reacceleration of high-energy electrons.
Comments12 pages, 4 figures, accepted by ApJ
