$El\ Ascua$: An ultra-luminous, radio-loud, Compton-thick AGN at $z\sim 3.8$ hiding in plain sight revealed by MINERVA multi-band MIRI observations
Year: 2026
Type: preprint
Abstract: Heavily dust-obscured active galactic nuclei (AGN) are crucial for understanding supermassive black hole growth. Using multi-band MIRI photometry from the MINERVA survey, we report the discovery in the UDS field of an extremely mid-infrared bright Compton-thick AGN (CT AGN) at $z \sim 3.8$, \textit{el Ascua} (the Ember). The AGN and/or its host galaxy is detected at 870\,$μ$m with ALMA and at 1.4\,GHz with the VLA. With UV-to-radio spectral energy distribution modeling, we estimate that the dusty host galaxy has a stellar mass of $\log\left( M_\star / M_\odot \right)=10.82 \pm 0.57$ and a star formation rate of ${\rm{SFR}} =157 \pm 8 \,M_\odot\,{\rm yr^{-1}}$, and we confirm the presence of a powerful dusty AGN with an intrinsic accretion luminosity of $\log\left( L_{\rm{acc}} /{\rm erg\,s^{-1}} \right)=47.12 \pm 0.58$. CT obscuration is revealed by comparing the upper limit on the X-ray luminosity over $2-10 \,{\rm{keV}}$ with the $6 \,{\rmμ{m}}$ mid-IR AGN luminosity. We additionally find evidence for a radio excess by comparing its total IR-to-radio ratio to those of typical star-forming galaxies and radio-quiet AGN, implying that \textit{el Ascua} could be a rare radio-loud CT AGN. With an extremely high ratio between black hole accretion rate and SFR, the AGN is likely nearing the peak of a deeply obscured phase of black hole growth before AGN feedback blows away the obscuring material. Our work demonstrates the power of MIRI to reveal heavily obscured AGN missing from our supermassive black hole census.
Source: arXiv (Cornell University)
Authors: Cloonan, Aidan P., Vidal, Edgar P., Pope, Alexandra, Sajina, Anna, Martis, Nicholas S., Asada, Yoshihisa, Cooper, Olivia R., Muzzin, Adam, Alberts, Stacey, Antwi-Danso, Jacqueline, Brammer, Gabriel, Cutler, Sam E., Iyer, Kartheik G., Labbé, Ivo, Marchesini, Danilo, Miller, Tim B., Mitsuhashi, Ikki, Robbins, Luke, Sarrouh, Ghassan T. E., Sharma, Monu, Stefanon, Mauro, Suess, Katherine A., Whitaker, Katherine E., Willott, Chris J., Dayal, Pratika, de Graaff, Anna, Forrest, Ben, Glazebrook, Karl, Greene, Jenny E., Hargraves, Kelsey, Jarvis, William W. H., Lyon, Daniel J., McConachie, Ian, Noirot, Gaël, Pratt, Veronica, Wang, Bingjie
Institutions: University of Ljubljana, Space Telescope Science Institute, European Space Agency, University of Toronto, University of Massachusetts Amherst, Columbia University, Swinburne University of Technology, Tufts University, Northwestern University, Universitat de València, Herzberg Institute of Astrophysics, National Research Council Canada, Max Planck Institute for Astronomy, University of Colorado Boulder, Princeton University, Queensland University of Technology, University of Wisconsin–Madison
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, California Institute of Technology, Canadian Foundation for AIDS Research, Canarie, Space Telescope Science Institute, Danmarks Grundforskningsfond, Alliance de recherche numérique du Canada, University of Massachusetts Amherst, Canadian Space Agency, Natural Sciences and Engineering Research Council of Canada
OpenAlex ID: W7223966769