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Funding for this research was provided by:
EC ∣ ERC ∣ HORIZON EUROPE European Research Council (771282)
EC ∣ European Research Council (101076343)
Agencia Nacional de Investigación y Desarrollo (FB210003)
Agencia Nacional de Investigación y Desarrollo (FB210003)
ANID ∣ Fondo Nacional de Desarrollo Científico y Tecnológico (1181620)
Simons Foundation (00001470)
Research Council of Finland (317383)
National Science Foundation (1430284)
Article Title: PKS 2131−021—Discovery of Strong Coherent Sinusoidal Variations from Radio to Optical Frequencies: Compelling Evidence for a Blazar Supermassive Black Hole Binary
Journal Title: The Astrophysical Journal
Article Type: paper
Copyright Information: © 2025. The Author(s). Published by the American Astronomical Society.
Publication dates
Date Received: 2024-07-12
Date Accepted: 2025-03-24
Online publication date: 2025-05-14