TY - JOUR
T1 - The Deepest GLIMPSE of a Dense Gas Cocoon Enshrouding a Little Red Dot
AU - Kokorev, Vasily
AU - Chisholm, John
AU - Naidu, Rohan P.
AU - Fujimoto, Seiji
AU - Atek, Hakim
AU - Brammer, Gabriel
AU - Finkelstein, Steven L.
AU - Akins, Hollis B.
AU - Berg, Danielle A.
AU - Furtak, Lukas J.
AU - Fei, Qinyue
AU - Hsiao, Tiger Yu Yang
AU - Labbé, Ivo
AU - Matthee, Jorryt
AU - Muñoz, Julian B.
AU - Oesch, Pascal A.
AU - Pan, Richard
AU - Rinaldi, Pierluigi
AU - Saldana-Lopez, Alberto
AU - Schaerer, Daniel
AU - Volonteri, Marta
AU - Zitrin, Adi
N1 - Publisher Copyright:
© 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
PY - 2026/6/20
Y1 - 2026/6/20
N2 - The detection of strong Balmer breaks and absorption features in Little Red Dots (LRDs) suggests they host active galactic nuclei embedded within dense gas envelopes, potentially powered by super-Eddington accretion. We present GLIMPSE-17775, a luminous (Lbol ∼ 1045 erg s−1) LRD at z = 3.501 behind Abell S1063 (μ ∼ 2), observed with deep JWST/NIRCam and a ∼20 hr (80 hr delensed) NIRSpec G395M spectrum. The data reveal over 40 emission and absorption features, including a rich forest of low-ionization Fe ii lines and numerous broad hydrogen recombination transitions. We use this depth to test the dense-gas interpretation through five independent diagnostics. Nearly all permitted lines show exponential wings with consistent FWHM, a signature of Thomson scattering requiring ne ≳ 108 cm−3. Adopting this width yields MBH ∼ 106.7M⊙, a factor of 10 lower than Gaussian fits, and λEdd ∼ 1.8. Additional diagnostics support the same picture: a pronounced Balmer break (fν,4050/fν,3670 = 2.0 ± 0.1), enhanced He i λ7065 and λ10830 with P-Cygni absorption, Bowen-fluorescent O i λ8446–λ11290 emission requiring Lyβ pumping, and 16 Fe ii lines matching fluorescence models. These features indicate a dense (n ∼ 108 cm−3), partially ionized cocoon where scattering and fluorescence dominate line formation, providing strong evidence that at least some LRDs are powered by super-Eddington black hole growth in the early Universe.
AB - The detection of strong Balmer breaks and absorption features in Little Red Dots (LRDs) suggests they host active galactic nuclei embedded within dense gas envelopes, potentially powered by super-Eddington accretion. We present GLIMPSE-17775, a luminous (Lbol ∼ 1045 erg s−1) LRD at z = 3.501 behind Abell S1063 (μ ∼ 2), observed with deep JWST/NIRCam and a ∼20 hr (80 hr delensed) NIRSpec G395M spectrum. The data reveal over 40 emission and absorption features, including a rich forest of low-ionization Fe ii lines and numerous broad hydrogen recombination transitions. We use this depth to test the dense-gas interpretation through five independent diagnostics. Nearly all permitted lines show exponential wings with consistent FWHM, a signature of Thomson scattering requiring ne ≳ 108 cm−3. Adopting this width yields MBH ∼ 106.7M⊙, a factor of 10 lower than Gaussian fits, and λEdd ∼ 1.8. Additional diagnostics support the same picture: a pronounced Balmer break (fν,4050/fν,3670 = 2.0 ± 0.1), enhanced He i λ7065 and λ10830 with P-Cygni absorption, Bowen-fluorescent O i λ8446–λ11290 emission requiring Lyβ pumping, and 16 Fe ii lines matching fluorescence models. These features indicate a dense (n ∼ 108 cm−3), partially ionized cocoon where scattering and fluorescence dominate line formation, providing strong evidence that at least some LRDs are powered by super-Eddington black hole growth in the early Universe.
KW - Active galactic nuclei (16)
KW - Black holes (162)
KW - Galaxy evolution (594)
UR - https://www.scopus.com/pages/publications/105041342690
U2 - 10.3847/1538-4357/ae4ed7
DO - 10.3847/1538-4357/ae4ed7
M3 - Article
AN - SCOPUS:105041342690
SN - 0004-637X
VL - 1004
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 153
ER -