Multiwavelength periodicity study of Markarian 501

Abstract

Context: Active Galactic Nuclei are highly variable emitters of electromagnetic waves from the radio to the gamma-ray regime. This variability may be periodic, which in turn could be the signature of a binary black hole. Systems of black holes are strong emitters of gravitational waves whose amplitude depends on the binary orbital parameters as the component mass, the orbital semi-major-axis and eccentricity. Aims: It is our aim to prove the existence of periodicity of the AGN Markarian 501 from several observations in different wavelengths. A simultaneous periodicity in different wavelengths provides evidence for bound binary black holes in the core of AGN. Methods: Existing data sets from observations by Whipple, SWIFT, RXTE and MAGIC have been analysed with the Lomb-Scargle method, the epoch folding technique and the SigSpec software. Results: Our analysis shows a 72-day period, which could not be seen in previous works due to the limited length of observations. This does not contradict a 23-day period which can be derived as a higher harmonic from the 72-day period.

9 pages, 15 figures, accepted at A&A

References in corpus (6)

• Variable VHE gamma-ray emission from Markarian 501
• SigSpec - I. Frequency- and Phase-Resolved Significance in Fourier Space
• X-ray Detection of the Proto Supermassive Binary Black Hole at the Centre of Abell 400
• Modeling of Emission Signatures of Massive Black Hole Binaries: I Methods
• Supermassive binary black holes among cosmic gamma-ray sources
• A possible disk mechanism for the 23d QPO in Mkn~501

Cited by in corpus (6)

• Blazar Mrk 501 shows rhythmic oscillations in its $\gamma$-ray emission
• Multi-color optical monitoring of Mrk 501 from 2010 to 2015
• Electromagnetic signatures of supermassive black hole binaries resolved by PTAs
• Search for intra-day optical variability in Mrk 501
• Not so Swift: 20 years of multiwavelength observations of Mrk 421 and Mrk 501
• A Supermassive Binary Black Hole Candidate in Mrk 501