A Targeted Gamma-Ray Search of Five Prominent Galaxy Merger Systems with 17 years of Fermi-LAT Data

Galaxy mergers are among the most energetic astrophysical phenomena, driving intense star formation and potentially fueling cosmic ray acceleration, which can produce high energy $γ$-ray emission through hadronic processes. We present a targeted search for $γ$-ray emission from five prominent galaxy merger systems, NGC~3256, NGC~660, UGC~813/816, UGC~12914/12915, and VV~114 using 16.8 years of Fermi-LAT data in the 1--300~GeV energy range. Employing a binned maximum likelihood analysis, we model the emission with power-law spectra and derive spectral energy distributions (SEDs) to constrain $γ$-ray fluxes and spectral indices. Marginal detections are found for NGC~3256 (TS = 15.4, ~3.51$σ$) and NGC~660 (TS = 8.16, ~2.39$σ$), with photon fluxes of (7.21 ± 3.17) × 10⁻¹¹ and (8.28 ± 3.56) × 10⁻¹¹ ph cm⁻² s⁻¹, respectively, suggesting merger driven star formation contributes to $γ$-ray emission. The remaining systems yield non-detections (TS $< 5$). This is the first targeted study of $γ$-ray emission from these aforementioned galaxy merger systems.