The Millimeter/X-Ray Relation in Rapidly Accreting Supermassive Black Holes at z < 0.16
Journal article, 2026
A tight correlation between nuclear millimeter and X-ray emission has recently been found in nearby (z < 0.01) and low-Eddington ratio (λEdd < 0.1) radio-quiet active galactic nuclei (AGNs), suggesting a common origin in the hot X-ray corona. We test this relation in nine more distant AGNs (z ∼ 0.06–0.16) with higher bolometric luminosities ( (Formula presented) log(Lbol/ergs−1)=45.3 –46.3), Eddington ratios (λEdd = 0.19–0.85), and X-ray bolometric corrections (κ = 29–194), selected from the Burst Alert Telescope (BAT) survey. We obtained observations with Swift at 2–10 keV and quasi-simultaneous observations with the Atacama Large Millimeter/submillimeter Array at 100 GHz with high angular resolution (<0 (Formula presented) .″ 14 arcsec). We find that these high-luminosity AGNs lie above the millimeter/X-ray correlation defined by lower-luminosity sources. A joint fit to both samples yields a second-degree polynomial with an intrinsic scatter of 0.32 dex. Furthermore, the millimeter emission correlates linearly with both the UV disk luminosity and Lbol, with intrinsic scatters of 0.45 and 0.35 dex, respectively. We propose that the deviation from the linear millimeter/X-ray relation arises from a two-component coronal electron population: thermal electrons that produce X-rays, but become less efficient at higher luminosities, and nonthermal electrons that produce millimeter emission and remain tied to Lbol. Additional millimeter emission from outflow-driven shocks may also contribute, though spectral energy distribution modeling and spectral index studies favor a coronal origin.
X-ray active galactic nuclei (2035)
Submillimeter astronomy (1647)
Supermassive black holes (1663)
Active galactic nuclei (16)
Author
Sophie M. Venselaar
University of Geneva
Diego Portales University
C. Ricci
Diego Portales University
Beijing University of Technology
University of Geneva
Santiago Del Palacio
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Kriti K. Gupta
Ghent university
University of Liège
Leibniz Association
Chin Shin Chang
University of Geneva
Atacama Large Millimeter Submillimeter Array
Roberto Serafinelli
Osservatorio Astronomico di Roma
Diego Portales University
M. Magno
Texas A&M University
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
Richard Mushotzky
University of Maryland
E. Shablovinskaya
Max Planck Society
Taiki Kawamuro
Osaka University
E. Treister
Universidad de Tarapacá
Jacob S. Elford
Diego Portales University
Susanne Aalto
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
G. Privon
University of Florida
National Radio Astronomy Observatory
University of Virginia
Michael J. Koss
Eureka Scientific
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 1005 1 48Subject Categories (SSIF 2025)
Fusion, Plasma and Space Physics
Astronomy, Astrophysics, and Cosmology
DOI
10.3847/1538-4357/ae6da8