发表机构
Friedrich-Alexander-Universität Erlangen-Nürnberg; Cherenkov Telescope Array Observatory; Max-Planck-Institut für Kernphysik（埃尔朗根-纽伦堡大学; 切伦科夫望远镜阵列天文台; 马克斯·普朗克核物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究利用DBSCAN算法对费米-LAT 4FGL目录源进行聚类分析，通过比较扩展源和多源模型，识别出可能遗漏的扩展源，发现多个新候选，空间聚类结合模型比较可补充现有搜索，帮助发现遗漏扩展源。
AI 中文摘要
自2008年费米大面积望远镜（LAT）发射以来，已探测到数千个源，其中许多未关联。一些可能是目录中由多个点状条目表示的扩展源。对HESS J1813 - 178重新解释为单个扩展源促使系统搜索更多遗漏的扩展源。我们应用DBSCAN算法对5 GeV至1 TeV能量范围内链接尺度为$\epsilon = 0.3^\circ$的4FGL源进行聚类，每个聚类至少包含一个未关联源及最多一个选定类别（如脉冲星等）的扩展或点状关联源。使用Fermipy比较扩展源和多源模型并对候选源进行光谱和形态表征，聚焦银道面。结果识别出48个包含124个源的聚类，8个通过质量选择的聚类中扩展源模型在统计上更优。与2FGES和HGPS交叉匹配显示5个与已知扩展源重叠，另外3个是新的扩展源候选。结论是空间聚类结合基于似然的模型比较可发现费米-LAT目录中遗漏的扩展源并补充现有搜索。
英文摘要
Many Fermi Large Area Telescope (LAT) sources remain unassociated. Some may be extended sources represented by multiple catalog entries, as found for HESS J1813-178. We search for clusters of unassociated Fermi-LAT sources and test whether single extended-source models describe them better than multiple catalog sources. We applied DBSCAN to 4FGL sources with a linking scale of $0.3^\circ$ over 5 GeV-1 TeV. Each cluster contains at least one unassociated source and up to one extended or point-like associated source from selected categories, including pulsars, pulsar wind nebulae and supernova remnants. Using Fermipy, we compared extended- and multiple-source models and characterized each candidate spectrally and morphologically, focusing on the Galactic plane. We identified 48 clusters containing 124 sources, each with at least one unassociated source. For all 8 clusters passing our quality selection, an extended-source model is statistically preferred. At linking scales of $0.4^\circ$ and $0.5^\circ$, all 8 clusters retain their core sources. Cross-matches with the Second Fermi Galactic Extended Sources Catalog (2FGES) and the HESS Galactic Plane Survey (HGPS) showed that 5 clusters overlap known extended sources. The other 3 clusters, including one cluster with a morphology dependent on the interstellar emission model, have no counterpart in either catalog and are new extended-source candidates. Spatial clustering combined with likelihood-based model comparison can uncover extended sources missed in the Fermi-LAT catalog and complements existing searches.
CommentsPublished in Astronomy & Astrophysics
Journal refA&A 713, A92 (2026)
DOI：10.1051/0004-6361/202660645
