Molecular clouds and gamma-ray sources associated with J2108. Left: OPU ¹²CO(J = 2 → 1) emission map towards the Cyg-OB7 association (de la Fuente et al. 2023). The molecular clouds [MML2017]4607 and [FKT-MC]2022 are indicated with ellipses. The angular resolution of the map is 3′. Right: Fermi-LAT TS map above 2 GeV in the region around J2108 adapted from Fig. 3 of Abe et al. (2023). The 95% positional uncertainty of 4FGL J2108.0+5155 is shown as a green ellipse. The cyan circles (radius of 0.14° and 0.26°) correspond to the 95% positional uncertainty and 95% UL of J2108, respectively.