Multiwavelength analysis of Fermi-LAT blazars with high-significance periodicity: detection of a long-term rising emission in PG 1553+113

Peñil, P.; Westernacher-Schneider, J. R.; Ajello, M.; Domínguez, A.; Buson, S.; Otero-Santos, J.; Marcotulli, L.; Torres-Albà, N.; Zrake, J.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society

Advertised on:
2
2024
Number of authors
9
IAC number of authors
1
Citations
4
Refereed citations
4
Description
Blazars display variable emission across the entire electromagnetic spectrum, with time-scales that can range from a few minutes to several years. Our recent work has shown that a sample of five blazars exhibit hints of periodicity with a global significance ${\gtrsim}2\, \sigma$ at γ-ray energies, in the range of 0.1 GeV < E < 800 GeV. In this work, we study their multiwavelength emission, covering the X-ray, ultraviolet, optical, and radio bands. We show that three of these blazars present similar periodic patterns in the optical and radio bands. Additionally, fluxes in the different bands of the five blazars are correlated, suggesting a co-spatial origin. Moreover, we detect a long-term (≈10 yr) rising trend in the light curves of PG 1553+113, and we use it to infer possible constraints on the binary black hole hypothesis.