A Tight Correlation Between Millimeter and X-ray Emission in Accreting Massive Black Holes from <100 Milliarcsecond-resolution ALMA Observations

Abstract

Recent studies have proposed that the nuclear millimeter continuum emission observed in nearby active galactic nuclei (AGN) could be created by the same population of electrons that gives rise to the X-ray emission that is ubiquitously observed in accreting black holes. We present the results of a dedicated high spatial resolution ($\sim$60-100 milliarcsecond) ALMA campaign on a volume-limited ($<50$ Mpc) sample of 26 hard X-ray ($>10$ keV) selected radio-quiet AGN. We find an extremely high detection rate (25/26 or $94_{-6}^{+3}\%$), which shows that nuclear emission at mm-wavelengths is nearly ubiquitous in accreting SMBHs. Our high-resolution observations show a tight correlation between the nuclear (1-23 pc) 100GHz and the intrinsic X-ray emission (1$\sigma$ scatter of $0.22$ dex). The ratio between the 100GHz continuum and the X-ray emission does not show any correlation with column density, black hole mass, Eddington ratio or star formation rate, which suggests that the 100GHz emission can be used as a proxy of SMBH accretion over a very broad range of these parameters. The strong correlation between 100GHz and X-ray emission in radio-quiet AGN could be used to estimate the column density based on the ratio between the observed 2-10keV ($F_{2-10\mathrm{keV}}^{\mathrm{obs}}$) and 100GHz ($F_{100\mathrm{GHz}}$) fluxes. Specifically, a ratio $\log (F_{2-10\mathrm{keV}}^{\mathrm{obs}}/F_{100\mathrm{GHz}})\le 3.5$ strongly suggests that a source is heavily obscured [$\log (N_{\mathrm{H}}/\mathrm{c}{\mathrm{m}}^{-2})\gtrsim 23.8$]. Our work shows the potential of ALMA continuum observations to detect heavily obscured AGN (up to an optical depth of one at 100GHz, i.e. $N_{\mathrm{H}}\simeq 10^{27}\mathrm{c}{\mathrm{m}}^{-2}$), and to identify binary SMBHs with separations $<100$ pc, which cannot be probed by current X-ray facilities.

ApJL in press

References in corpus (23)

• BAT AGN Spectroscopic Survey - V. X-ray properties of the Swift/BAT 70-month AGN catalog
• X-ray reverberation around accreting black holes
• Simultaneous X-ray/optical/UV snapshots of active galactic nuclei from XMM-Newton: spectral energy distributions for the reverberation mapped sample
• The close environments of accreting massive black holes are shaped by radiative feedback
• BAT AGN Spectroscopic Survey I: Spectral Measurements, Derived Quantities, and AGN Demographics
• Occultation measurement of the size of the X-ray emitting region in the Active Galactic Nucleus of NGC 1365
• On the origin of radio emission in radio quiet quasars
• Reverberation mapping of Active Galactic Nuclei: from X-ray corona to dusty torus
• BASS XXII: The BASS DR2 AGN Catalog and Data
• The Complete Infrared View of Active Galactic Nuclei from the 70-month Swift/BAT Catalog
• BASS XXV: DR2 Broad-line Based Black Hole Mass Estimates and Biases from Obscuration
• BAT AGN Spectroscopic Survey XXI: The Data Release 2 Overview
• BASS XXXVII: The role of radiative feedback in the growth and obscuration properties of nearby supermassive black holes
• BASS XXXII: Studying the Nuclear Mm-wave Continuum Emission of AGNs with ALMA at Scales $\lesssim$ 100-200 pc
• BASS XXVI: DR2 Host Galaxy Stellar Velocity Dispersions
• Compton-Thick AGN in the NuSTAR era VI: The observed Compton-thick fraction in the Local Universe
• UGC 4211: A Confirmed Dual Active Galactic Nucleus in the Local Universe at 230 pc Nuclear Separation
• BAT AGN Spectroscopic Survey -- XV: The High Frequency Radio Cores of Ultra-hard X-ray Selected AGN
• RefleX: X-ray absorption and reflection in active galactic nuclei for arbitrary geometries
• Unveiling the Nature of Coronae in Active Galactic Nuclei through Sub-mm Observations
• BAT AGN Spectroscopic Survey XXVII: Scattered X-Ray Radiation in Obscured Active Galactic Nuclei
• Radio Properties of the BAT AGN: the FIR-Radio Relation, the Fundamental Plane, and the Main Sequence of Star Formation
• Ray-tracing simulations and spectral models of X-ray radiation in dusty media

Cited by in corpus (18)

• Deciphering the imprint of AGN feedback in Seyfert galaxies: Nuclear-scale molecular gas deficits
• SDSS1335+0728: The awakening of a $\sim 10^6{M}_{\odot }$ black hole
• The radio properties of the JWST-discovered AGN
• BASS-XL: X-ray variability properties of unobscured Active Galactic Nuclei
• Joint ALMA/X-ray monitoring of the radio-quiet type 1 AGN IC 4329A
• The Centimeter to Submillimeter Broad Band Radio Spectrum of the Central Compact Component in A Nearby Type-II Seyfert Galaxy NGC 1068
• BASS XLVII: 22 GHz Radio Atlas of Swift-BAT Selected AGN
• Millimeter emission from supermassive black hole coronae
• High-energy Emission from Turbulent Electron-ion Coronae of Accreting Black Holes
• Detection of millimeter-wave coronal emission in a quasar at cosmological distance using microlensing
• ALMA polarimetry of radio-quiet AGNs
• XMM-Newton --NuSTAR monitoring campaign of the Seyfert 1 galaxy IC 4329A
• ALMA observation of evolving magnetized corona in the radio-quiet changing-state AGN NGC 1566
• BASS XLV: Quantifying AGN Selection Effects in the Chandra COSMOS-Legacy Survey with BASS
• ALMA discovery of Punctum -- a highly polarized mm source in nuclear starburst galaxy NGC 4945
• Probing Heavily Obscured AGN in Major Galaxy Mergers Using the mm-X-ray Correlation
• Torus feeding and outflow launching in the active nucleus of the Circinus galaxy
• Supermassive Black Hole Winds in X-rays: SUBWAYS IV. Tracing Radio Emission and Unveiling the Role of Winds