A γ-ray Quasi-periodic Modulation in the Blazar PKS 0301–243?

Abstract

We report a nominally high-confidence γ -ray quasi-periodic modulation in the blazar PKS 0301–243. For this target, we analyze its Fermi -LAT Pass 8 data from 2008 August to 2017 May. Two techniques, i.e., maximum likelihood optimization and exposure-weighted aperture photometry, are used to build the γ -ray light curves. Then, both the Lomb–Scargle periodogram and the weighted wavelet Z-transform are applied to the light curves to search for period signals. A quasi-periodicity with a period of 2.1 ± 0.3 yr appears at the significance level of , although it should be noted that this putative quasi-period variability is seen in a data set that is barely four times longer. We speculate that this γ -ray quasi-periodic modulation may be evidence of a binary supermassive black hole.