GeV ?-Ray Emission of Compact Steep-spectrum Source 4C +39.23B

Thirteen yr observation data of 4FGL J0824.9+3915 with the Large Area Telescope on board Fermi Gamma Ray Space (Fermi/LAT) are analyzed for revisiting whether 4C +39.23B, a compact steep-spectrum (CSS) source closed to flat-spectrum radio quasar (FSRQ) +39.23A in $\gamma$-ray emitting region J0824.9+3915, is emitter. We find that time-integrated emission overwhelmingly dominated by +39.23A. It shows significant variability at 6.7$\sigma$ confidence level and average flux 0.1--300 GeV energy band $(1.60\pm 0.15)\times10^{-8}$ ph cm$^{-2}$ s$^{-1}$ power-law photon spectral index $2.48\pm0.05$. During MJD 57500--58500, low state steady flux. Analyzed Fermi/LAT this time interval, it found TS values from +39.23B $\sim5$ $\sim 31$, respectively, indicating interval CSS +39.23B. The derived $(9.40\pm4.10)\times 10^{-9}$ cm $^{-2}$ $\Gamma_{\gamma}=2.45\pm0.17$. Attributing distribution (SED) radiations its core extended region, we show SED can be represented two-zone leptonic model. Its contributed region. magnetic field strength Doppler boosting factor 0.13 G 6.5. Comparing other $\gamma$-emitting CSSs symmetric objects (CSOs) $\Gamma_{\gamma}-L_{\gamma}$ plane, resembles CSSs.