2026/07/24 by Ajay Sharma, Debanjan Bose
#astro-ph.HE
We report a clear observational evidence for jet precession and nutation manifested in the gamma-ray emissions of the blazar PKS 1424-41. An analysis of ∼16 yr of Fermi-LAT observations reveals three distinct and superimposed quasi-periodic oscillations (QPOs), with characteristic timescales of ∼5.26 yr, ∼0.96 yr and ∼1.3 yr. The longer timescale is detected with a local significance of ∼ 4.1σ (99.9958% confidence) and a global significance of ∼ 2.45σ (98.5714% confidence). The shorter timescales (∼ 0.96 yr and ∼ 1.3 yr) both show local significances exceeding 3σ. To interpret the origin of these modulations, we examine two physically motivated scenarios: Lense-Thirring precession of a misaligned accretion disk and orbital-driven jet precession in a binary supermassive black hole (BSBH) system. We model the gamma-ray variability using a compound framework that incorporates jet precession together with intrinsic jet rotation (nutation), which successfully reproduces the observed year-like QPOs. Our results indicate that the long-term, persistent ∼5.26 yr oscillation is most consistent with a BSBH origin, while the shorter year-like QPO modulation can be naturally attributed to rotation or wobbling of the jet axis. If PKS 1424-41 hosts a supermassive black hole binary, it represents a promising target for future space-borne gravitational-wave observatories such as the Laser Interferometer Space Antenna (LISA), providing an independent probe of supermassive black hole binaries.