El Ascua: An ultra-luminous, radio-loud, Compton-thick AGN at z∼ 3.8 hiding in plain sight revealed by MINERVA multi-band MIRI observations

@misc{cloonan2026ascua,
  title = {{$El\ Ascua$: An ultra-luminous, radio-loud, Compton-thick AGN at $z\sim 3.8$ hiding in plain sight revealed by MINERVA multi-band MIRI observations}},
  author = {Aidan P. Cloonan and Edgar P. Vidal and Alexandra Pope and Anna Sajina and Nicholas S. Martis and Yoshihisa Asada and Olivia R. Cooper and Adam Muzzin and Stacey Alberts and Jacqueline Antwi-Danso and Gabriel Brammer and Sam E. Cutler and Kartheik G. Iyer and Ivo Labbé and Danilo Marchesini and Tim B. Miller and Ikki Mitsuhashi and Luke Robbins and Ghassan T. E. Sarrouh and Monu Sharma and Mauro Stefanon and Katherine A. Suess and Katherine E. Whitaker and Chris J. Willott and Pratika Dayal and Anna de Graaff and Ben Forrest and Karl Glazebrook and Jenny E. Greene and Kelsey Hargraves and William W. H. Jarvis and Daniel J. Lyon and Ian McConachie and Gaël Noirot and Veronica Pratt and Bingjie Wang},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.33155},
  eprint = {2610.33155},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.33155},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - El Ascua: An ultra-luminous, radio-loud, Compton-thick AGN at z∼ 3.8 hiding in plain sight revealed by MINERVA multi-band MIRI observations
AU  - Aidan P. Cloonan
AU  - Edgar P. Vidal
AU  - Alexandra Pope
AU  - Anna Sajina
AU  - Nicholas S. Martis
AU  - Yoshihisa Asada
AU  - Olivia R. Cooper
AU  - Adam Muzzin
AU  - Stacey Alberts
AU  - Jacqueline Antwi-Danso
AU  - Gabriel Brammer
AU  - Sam E. Cutler
AU  - Kartheik G. Iyer
AU  - Ivo Labbé
AU  - Danilo Marchesini
AU  - Tim B. Miller
AU  - Ikki Mitsuhashi
AU  - Luke Robbins
AU  - Ghassan T. E. Sarrouh
AU  - Monu Sharma
AU  - Mauro Stefanon
AU  - Katherine A. Suess
AU  - Katherine E. Whitaker
AU  - Chris J. Willott
AU  - Pratika Dayal
AU  - Anna de Graaff
AU  - Ben Forrest
AU  - Karl Glazebrook
AU  - Jenny E. Greene
AU  - Kelsey Hargraves
AU  - William W. H. Jarvis
AU  - Daniel J. Lyon
AU  - Ian McConachie
AU  - Gaël Noirot
AU  - Veronica Pratt
AU  - Bingjie Wang
PY  - 2026
DA  - 2026/10/23
PB  - arXiv
DO  - 10.48550/arxiv.2610.33155
UR  - https://arxiv.org/abs/2610.33155
AB  - 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 ∼ 3.8, \textit{el Ascua} (the Ember). The AGN and/or its host galaxy is detected at 870\,μm 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( M_⋆ / M_⊙ )=10.82 ± 0.57 and a star formation rate of SFR =157 ± 8 M_⊙ yr^−1, and we confirm the presence of a powerful dusty AGN with an intrinsic accretion luminosity of log( L_acc /erg s^−1 )=47.12 ± 0.58. CT obscuration is revealed by comparing the upper limit on the X-ray luminosity over 2−10 keV with the 6 μm 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.
ER  -