Статья

The Unanticipated Phenomenology of the Blazar PKS 2131–021: A Unique Supermassive Black Hole Binary Candidate

S. O’NeillOwens Valley Radio Observatory, California Institute of Technology, Pasadena, CA 91125, USA; [email protected]S. KiehlmannDepartment of Physics and Institute of Theoretical and Computational Physics, University of Crete, 71003 Heraklion, GreeceA. C. S. ReadheadInstitute of Astrophysics, Foundation for Research and Technology-Hellas, GR-71110 Heraklion, GreeceM. F. Aller2 Department of Astronomy, University of Michigan, 323 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109, USAR. D. BlandfordKavli Institute for Particle Astrophysics and Cosmology, Department of Physics, 20 Stanford University, Stanford, CA 94305, USAIoannis LiodakisFinnish Centre for Astronomy with ESO (FINCA), University of Turku, FI-20014 University of Turku, FinlandM. L. ListerDepartment of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907, USAP. MrózAstronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, PolandC. P. O’DeaDepartment of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, CanadaT. J. PearsonOwens Valley Radio Observatory, California Institute of Technology, Pasadena, CA 91125, USA; [email protected]Vikram RaviOwens Valley Radio Observatory, California Institute of Technology, Pasadena, CA 91125, USA; [email protected]Michele VallisneriJet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USAKieran ClearyOwens Valley Radio Observatory, California Institute of Technology, Pasadena, CA 91125, USA; [email protected]M. J. GrahamDivision of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USAKeith GraingeJodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, Manchester M13 9PL, UKMark HodgesOwens Valley Radio Observatory, California Institute of Technology, Pasadena, CA 91125, USA; [email protected]T. HovattaAalto University Metsähovi Radio Observatory, Metsähovintie 114, FI-02540 Kylmälä, FinlandA. LähteenmäkiAalto University Department of Electronics and Nanoengineering, P.O. Box 15500, FI-00076 Aalto, FinlandJames W. LambOwens Valley Radio Observatory, California Institute of Technology, Pasadena, CA 91125, USA; [email protected]T. Joseph W. LazioJet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USAW. Max-MoerbeckDepartamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, ChileV. PavlidouDepartment of Physics and Institute of Theoretical and Computational Physics, University of Crete, 71003 Heraklion, GreeceThomas A. PrinceDivision of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USAR. ReevesCePIA, Astronomy Department, Universidad de Concepción, Casilla 160-C, Concepción, ChileM. TornikoskiAalto University Metsähovi Radio Observatory, Metsähovintie 114, FI-02540 Kylmälä, FinlandP. V. de la ParraCePIA, Astronomy Department, Universidad de Concepción, Casilla 160-C, Concepción, ChileJ. A. ZensusMax-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany

2022en

ABI

Аннотация

Abstract Most large galaxies host supermassive black holes in their nuclei and are subject to mergers, which can produce a supermassive black hole binary (SMBHB), and hence periodic signatures due to orbital motion. We report unique periodic radio flux density variations in the blazar PKS 2131−021, which strongly suggest an SMBHB with an orbital separation of ∼0.001–0.01 pc. Our 45.1 yr radio light curve shows two epochs of strong sinusoidal variation with the same period and phase to within ≲2% and ∼10%, respectively, straddling a 20 yr period when this variation was absent. Our simulated light curves accurately reproduce the “red noise” of this object, and Lomb–Scargle, weighted wavelet Z -transform and least-squares sine-wave analyses demonstrate conclusively, at the 4.6 σ significance level, that the periodicity in this object is not due to random fluctuations in flux density. The observed period translates to 2.082 ± 0.003 yr in the rest frame at the z = 1.285 redshift of PKS 2131−021. The periodic variation in PKS 2131−021 is remarkably sinusoidal. We present a model in which orbital motion, combined with the strong Doppler boosting of the approaching relativistic jet, produces a sine-wave modulation in the flux density that easily fits the observations. Given the rapidly developing field of gravitational-wave experiments with pulsar timing arrays, closer counterparts to PKS 2131−021 and searches using the techniques we have developed are strongly motivated. These results constitute a compelling demonstration that the phenomenology, not the theory, must provide the lead in this field.

Идентификаторы

DOI: 10.3847/2041-8213/ac504b

Цитирования и источники

Цитирований: 4Использованных источников: 0

Показатели — AkademScholar · Скоро