What Is the Nature of Little Red Dots and what Is Not, MIRI SMILES Edition

Pérez-González, PG; Barro, G; Rieke, GH; Lyu, J; Rieke, M; Alberts, S; Williams, CC; Hainline, K; Sun, F; Puskás, D; Annunziatella, M; Baker, WM; Bunker, AJ; Egami, E; Ji, Z; Johnson, BD; Robertson, B; Rodríguez Del Pino, B; Rujopakarn, W; Shivaei, I; Tacchella, S; Willmer, CNA; Willott, C

Journal article

What Is the Nature of Little Red Dots and what Is Not, MIRI SMILES Edition

Abstract:: We study 31 little red dots (LRD) detected by JADES/NIRCam and covered by the SMILES/MIRI survey, of which ∼70% are detected in the two bluest MIRI bands and 40% in redder MIRI filters. The median/quartiles redshifts are z=6.95.97.7 (55% spectroscopic). The spectral slopes flatten in the rest-frame near-infrared, consistent with a 1.6 μm stellar bump but bluer than direct pure emission from active galactic nuclei (AGN) tori. The apparent dominance of stellar emission at these wavelengths for many LRDs expedites stellar mass estimation: the median/quartiles are logM⋆/M⊙=9.49.19.7 . The number density of LRDs is 10−4.0±0.1 Mpc−3, accounting for 14% ± 3% of the global population of galaxies with similar redshifts and masses. The rest-frame near-/mid-infrared (2–4 μm) spectral slope reveals significant amounts of warm dust (bolometric attenuation ∼3–4 mag). Our spectral energy distribution modeling implies the presence of <0.4 kpc diameter knots, heated by either dust-enshrouded OB stars or an AGN producing a similar radiation field, obscured by A(V) > 10 mag. We find a wide variety in the nature of LRDs. However, the best-fitting models for many of them correspond to extremely intense and compact starburst galaxies with mass-weighted ages 5–10 Myr, very efficient in producing dust, with their global energy output dominated by the direct (in the flat rest-frame ultraviolet and optical spectral range) and dust-recycled emission from OB stars with some contribution from an obscured AGN (in the infrared).

Publication status:: Published

Peer review status:: Peer reviewed

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APA Style

Pérez-González, P. G., Barro, G., Rieke, G. H., Lyu, J., Rieke, M., Alberts, S., Williams, C. C., Hainline, K., Sun, F., Puskás, D., Annunziatella, M., Baker, W. M., Bunker, A. J., Egami, E., Ji, Z., Johnson, B. D., Robertson, B., Rodríguez Del Pino, B., Rujopakarn, W., … Willott, C. (2024). What Is the Nature of Little Red Dots and what Is Not, MIRI SMILES Edition. The Astrophysical Journal, 968(1).

MLA Style

Pérez-González, PG, et al. “What Is the Nature of Little Red Dots and What Is Not, MIRI SMILES Edition.” The Astrophysical Journal, vol. 968, no. 1, 2024.

Chicago Style

Pérez-González, PG, G Barro, GH Rieke, et al. 2024. “What Is the Nature of Little Red Dots and What Is Not, MIRI SMILES Edition.” The Astrophysical Journal 968 (1).
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