The bremsstrahlung and π0 decay as gamma-ray source in 3C 273 and Geminga.

The experimental data from COS B sources can be fitted with the expected gamma-ray spectrum from π⁰ decay and bremsstrahlung for the thermal and non-thermal models in the case of matter spherically accreting onto collapsed objects. The authors compare spectra from thermal and non-thermal models with experimental measurements in the gamma and X-ray regions for 2CG 289+64 (3C 273) and 2CG 195+04 (Geminga) gamma-ray sources. The accreting process can explain the observed spectrum of 3C 273 but not that of Geminga. The identification of Geminga with a local source is more probable.