Little red dots are the dust-reddened, high-inclination counterparts of little blue dots under a super-Eddington unification model, with luminosity-dependent fractions peaking near 20% and obscured systems showing systematically higher black hole masses due to selection.
Do little red dots really form a distinct class of astronomical objects?
1 Pith paper cite this work. Polarity classification is still indexing.
abstract
JWST observations have identified a class of enigmatic sources known as "Little Red Dots" (LRDs). These have been interpreted as a distinct class of active galactic nuclei (AGN) and host galaxies, potentially involving "quasi-stars" or Black Hole stars (BH*). However, two questions remain: is there a clear discontinuity between LRDs and field galaxies, and do LRDs form a homogeneous population? In this work, we address these issues by introducing a continuous metric to evaluate the "LRDness" of galaxies. We measure their compactness ($\delta_{compact}$), the sharpness of the V-shaped spectral energy distribution ($\delta_{v-shape}$), and the strength of the broad Balmer line emission. We apply this approach to a sample of ~48,000 galaxies with photometric and ~5,000 with spectroscopic information, selected over ~750 arcmin^2. We find that V-shape prominence correlates strongly with morphology without a clear transition at common LRD selection thresholds: the fraction of compact galaxies rises continuously with V-shape intensity. Similarly, broad H$\alpha$ strength increases with both V-shape sharpness and compactness. The [N II] deficit is not an exclusive feature of LRDs but a global property of compact, metal-poor galaxies. Only the 3% most extreme LRDs present a prominent Balmer break (>3) of potentially non-stellar origin. LRDs and non-LRDs follow similar trends in the evolution of the Balmer decrement with V-shape sharpness, suggesting a shared physical origin, likely dust attenuation. Estimated dust masses (~4-7 x 10^4 M_{sun}) and luminosities are low enough to account for their non-detection by ALMA. We conclude that most LRDs do not represent a separate class of objects, but rather the extreme tail of a continuous distribution of galaxies and broad H$\alpha$ emitters, consistent with a classical broad line region and dust attenuation.
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astro-ph.GA 1years
2026 1verdicts
UNVERDICTED 1representative citing papers
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Little red dots as obscured little blue dots: relative abundances, luminosities, and black-hole masses
Little red dots are the dust-reddened, high-inclination counterparts of little blue dots under a super-Eddington unification model, with luminosity-dependent fractions peaking near 20% and obscured systems showing systematically higher black hole masses due to selection.