Lyα observations of Little Red Dots show luminosities and equivalent widths like normal star-forming galaxies but lower Lyα/Hα ratios and extended asymmetric emission, supporting a two-component model with host-scale gas.
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The Way We Tally Becomes the Tale: the Impact of Selection Strategies on the Inferred Evolution of Little Red Dots Across Cosmic Time
11 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
Little Red Dots (LRDs) have emerged as a key population linked to early black hole growth, yet photometric selections have predominantly targeted only the most extreme red systems, thereby shaping our current understanding of this new population of objects. In this work, we deliberately explore a broad range of optical redness while enforcing stringent compactness and visual inspection to ensure robustness and minimize contamination. Leveraging the depth and multiwavelength coverage of the JWST Advanced Deep Extragalactic Survey (JADES) data in the GOODS-North and GOODS-South fields, we construct the largest photometric census of LRDs to date in these fields, comprising 412 sources over $z\approx2\text{--}11$ across $\approx349.6$ arcmin$^2$. We show that classic extreme color cuts isolate only a minor fraction of this population ($\lesssim25\%$), while the majority of LRDs span a broader, largely unexplored parameter space. We quantify how selection strategies impact UV and optical luminosity functions and number density evolution, finding that current demographic trends of LRDs are strongly driven by selection biases and further limited by incomplete identification at both high and low redshift. Spectroscopically confirmed LRDs reveal a continuous range of spectral shapes, consistent with varying Active Galactic Nucleus (AGN) and host contributions in agreement with recent findings. Our results demonstrate that commonly adopted, purity-driven selections bias current demographic constraints toward the most extreme systems, potentially misrepresenting the diversity and evolution of the LRD population. Accounting for these selection effects is essential for interpreting LRDs and their role in early black hole growth.
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LRDs are reinterpreted as intermediate-mass super-Eddington systems with wind-driven pseudo-photospheres that explain their spectra and imply engine masses below 10^5 solar masses rather than overmassive black holes.
New stack-based strong-line calibrations from ~1500 spectra yield mass-metallicity relations at z=1-10 with decreasing metallicity toward higher redshift and no slope change, plus 50 EMPG candidates at 1-4% solar metallicity showing large scatter and opposite sSFR trends.
LRDs at z~3-7 exhibit an L_Hα,broad-L_bol scaling relation enhanced by a factor of ~40 compared to low-z Type 1 AGN, explained via Cloudy modeling with near-unity covering factor and high column density.
Narrow-line diagnostics on ~20 LRDs indicate that stellar photoionization alone cannot explain the observed ratios in many objects, implying anisotropic ionizing radiation from complex gas geometry.
JWST data on LRDs and LBDs show AGN-like excitation, strong Lyα with broad components, and X-ray weakness, implying clumpy or equatorial geometries around growing black holes rather than complete gas envelopes.
JWST IFU spectroscopy of six z~6 galaxies finds broad Balmer lines in two objects, a strong correlation of broad-line presence with Lyα luminosity yielding AGN fractions >77% above and <15% below 10^44 erg/s, plus extended star-forming gas in non-AGN hosts.
A sample of 36 spectroscopically confirmed LRDs shows broad-line detections in >90%, spectral variety including Balmer breaks and blackbody fits, H-alpha to 5100A continuum correlation, no redshift evolution, declining space density toward z~2 opposite normal AGNs, and clustering in ~10^11 solar mas
JADES DR5 delivers a public catalog of Bayesian-inferred stellar masses, SFRs, SFHs, dust, metallicities, and AGN contributions for ~500k galaxies via Prospector with an evolving SFMS prior.
Euclid identifies 16 massive compact galaxies with V-shaped SEDs at z>4, half as old as the universe at their redshift, mostly distinct from known AGN.
Number density of LRDs with L_bol ≳ 3×10^44 erg s^{-1} shows no evolution at z>2 and is ~350 times higher than model predictions at cosmic noon.
citing papers explorer
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Through the Veil: Ly$\alpha$ Illuminates the Host Galaxies of Little Red Dots
Lyα observations of Little Red Dots show luminosities and equivalent widths like normal star-forming galaxies but lower Lyα/Hα ratios and extended asymmetric emission, supporting a two-component model with host-scale gas.
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Little Red Dots as Intermediate Mass, Super-Eddington Engines: Insights from Type IIn Supernovae and The 1837-1856 Great Eruption of $\eta$ Carinae
LRDs are reinterpreted as intermediate-mass super-Eddington systems with wind-driven pseudo-photospheres that explain their spectra and imply engine masses below 10^5 solar masses rather than overmassive black holes.
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JADES: the mass-metallicity relation at $z=1-10$. New calibrations, extremely metal-poor galaxies, and chemical diversity
New stack-based strong-line calibrations from ~1500 spectra yield mass-metallicity relations at z=1-10 with decreasing metallicity toward higher redshift and no slope change, plus 50 EMPG candidates at 1-4% solar metallicity showing large scatter and opposite sSFR trends.
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A Scaling Relation of LRDs between Broad H$\alpha$ and Bolometric Luminosities: Enhanced Broad H$\alpha$ Emission Relative to Low-$z$ Type 1 AGN
LRDs at z~3-7 exhibit an L_Hα,broad-L_bol scaling relation enhanced by a factor of ~40 compared to low-z Type 1 AGN, explained via Cloudy modeling with near-unity covering factor and high column density.
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Constraints on the Gas Geometry Surrounding Little Red Dots through Narrow-Line Diagnostics
Narrow-line diagnostics on ~20 LRDs indicate that stellar photoionization alone cannot explain the observed ratios in many objects, implying anisotropic ionizing radiation from complex gas geometry.
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Little Red and Blue Dots: AGN-excited narrow lines, Lyman-$\alpha$ emission, and resemblance to standard quasars
JWST data on LRDs and LBDs show AGN-like excitation, strong Lyα with broad components, and X-ray weakness, implying clumpy or equatorial geometries around growing black holes rather than complete gas envelopes.
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Aether-SHELLQs: JWST integral-field spectroscopy of candidate obscured quasars at z ~ 6
JWST IFU spectroscopy of six z~6 galaxies finds broad Balmer lines in two objects, a strong correlation of broad-line presence with Lyα luminosity yielding AGN fractions >77% above and <15% below 10^44 erg/s, plus extended star-forming gas in non-AGN hosts.
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NEXUS: Abundance, Environments, and Spectral Diversity of Little Red Dots from the NIRSpec MSA Sample
A sample of 36 spectroscopically confirmed LRDs shows broad-line detections in >90%, spectral variety including Balmer breaks and blackbody fits, H-alpha to 5100A continuum correlation, no redshift evolution, declining space density toward z~2 opposite normal AGNs, and clustering in ~10^11 solar mas
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JWST Advanced Deep Extragalactic Survey (JADES) Data Release 5: stellar population catalogue for galaxies in GOODS-N and GOODS-S
JADES DR5 delivers a public catalog of Bayesian-inferred stellar masses, SFRs, SFHs, dust, metallicities, and AGN contributions for ~500k galaxies via Prospector with an evolving SFMS prior.
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Euclid: Scaled-up little red dots and other sources with v-shaped spectral energy distributions at z>4
Euclid identifies 16 massive compact galaxies with V-shaped SEDs at z>4, half as old as the universe at their redshift, mostly distinct from known AGN.
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No evolution in the number density of little red dots from cosmic dawn to cosmic noon
Number density of LRDs with L_bol ≳ 3×10^44 erg s^{-1} shows no evolution at z>2 and is ~350 times higher than model predictions at cosmic noon.