A 78- and 96- minute quasi-periodic gamma-ray oscillations in Sagittarius A*

Abstract

Using publicly available gamma-rays data from the Fermi satellite and the Fermitools package, we constructed 867-day light curves of Sagittarius A* to search for potential periodicities from 2008 to 2024. By applying statistical and computational inference methods, we used periodograms, a window function, unsupervised machine learning (K-Means), the Markov Chain Monte Carlo method, noise colour analysis, and phase-folding techniques. Additionally, the datasets were fitted with a Jacobi elliptical function using a likelihood approach. In total, 1,463,040 minutes were analysed. This analysis revealed a significant period of enhanced activity lasting ~78 minutes, followed by a quiescent phase of about ~18 minutes, resulting in a total quasi-periodic oscillation (QPO) of around 96 minutes.