LRD host galaxies show average metallicity 0.08 Z_sun with narrow stable range, challenging pristine-gas formation models while ruling out typical local AGN.
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Defines a sample of ~1300 SDSS quasars as Local Red Dots matching LRD photometric colors at z~0.4-0.8, with a V-shaped subset showing Balmer absorption and [NeV] emission, and SEDs modeled as reddened AGN plus host galaxy that match LRD stacks.
LRD-204851 at z=5.482 shows a thin bipolar elongation several kpc long traced by UV and optical lines, with double-peaked Lyα and tentative N V supporting a biconical cavity from the central engine.
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.
Spectroscopic study of 11 LRDs at z~4 finds AGN origin for optical emission via broad Hα correlations and introduces a clumpy envelope model with growth timescales of 10^5-10^7 years.
Self-gravitating disks heated by stars reach a universal optical effective temperature of 4000-4500 K independent of accretion rate, black hole mass, and viscosity, explaining Little Red Dots.
Little Red Dots show soft ionizing spectra consistent with massive stars, based on high H-alpha EWs and low HeII/H-beta ratios that rule out hard AGN spectra via Cloudy modeling.
LRDs are interpreted as high-inclination hyper-Eddington accreting SMBHs analogous to SS 433, with V-shaped SEDs, X-ray weakness, and Balmer breaks emerging from disk self-shielding geometry.
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.
Analysis of ~100 JWST LRDs finds redder, compact UV emission with Fe II/Mg II ~8-10 and correlations suggesting central red continuum (β_UV~0) beyond host galaxy contribution.
LRDs transition from underdense low-halo-mass environments at z>4 to typical galaxy conditions by z~3.5, with halo growth leading to larger sizes and SED changes that explain their disappearance at lower redshifts.
UV-bright companions to Little Red Dots provide Lyman-Werner fluxes of J21 ~ 10^2.5-10^5 that can suppress H2 cooling and enable direct collapse to massive black holes.
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.
Bayesian continuum fitting of 66 LRDs shows the BH* model fits ~6% best, rising to ~40% under AGN-disfavoring priors, with most objects stellar/AGN-dominated and possible evolutionary trends.
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
Variable column density and covering factor of three ionized absorbers in clumpy disk winds explain the X-ray variability in I Zw 1 with stable corona.
A z=1.715 radio-loud quasar exhibits a ~10,000 K blackbody UV continuum and three-component blackbody photometry, marking it as a candidate transitional Little Red Dot.
A bias-controlled quasar sample of ~2000 objects demonstrates that the X-ray-to-UV luminosity relation remains constant from redshift 0.7 to 5.
Simulations show VMS in star clusters reach 10^3-10^4 solar masses with dimensionless spins >10 under bloated accretion conditions, potentially forming spinning IMBHs that produce GW bursts like GW190521.
Non-LTE wind atmosphere models computed with CMFGEN reproduce the SED and Balmer decrement of most Little Red Dots when dust-attenuated with Av ~2, while predicting Fe II, O I, and Ca lines, but struggle to produce both a genuine Balmer break and strong lines simultaneously.
SKAO continuum surveys will detect radio emission from JWST AGN and LRDs and distinguish between Compton-thick absorption, intrinsically weak accretion, and dense gas cocoon scenarios.
citing papers explorer
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The metallicities of little red dot host galaxies: LRDs are metal poor, but not pristine
LRD host galaxies show average metallicity 0.08 Z_sun with narrow stable range, challenging pristine-gas formation models while ruling out typical local AGN.
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A Population of Little Red Dot-like Quasars in SDSS
Defines a sample of ~1300 SDSS quasars as Local Red Dots matching LRD photometric colors at z~0.4-0.8, with a V-shaped subset showing Balmer absorption and [NeV] emission, and SEDs modeled as reddened AGN plus host galaxy that match LRD stacks.
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Compact Core, Extended Reach: A Bipolar kpc-Scale Elongation in a Little Red Dot at $z \approx 5.5$
LRD-204851 at z=5.482 shows a thin bipolar elongation several kpc long traced by UV and optical lines, with double-peaked Lyα and tentative N V supporting a biconical cavity from the central engine.
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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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The Structure and Evolution of LRDs: Insights from JWST NIRSpec Medium and High Resolution Spectroscopy at $z\sim4$
Spectroscopic study of 11 LRDs at z~4 finds AGN origin for optical emission via broad Hα correlations and introduces a clumpy envelope model with growth timescales of 10^5-10^7 years.
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Spectral Appearance of Self-gravitating Disks Powered by Stellar Objects: Universal Effective Temperature in the Optical Continuum and Application to Little Red Dots
Self-gravitating disks heated by stars reach a universal optical effective temperature of 4000-4500 K independent of accretion rate, black hole mass, and viscosity, explaining Little Red Dots.
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The Missing Hard Photons of Little Red Dots: Their Incident Ionizing Spectra Resemble Massive Stars
Little Red Dots show soft ionizing spectra consistent with massive stars, based on high H-alpha EWs and low HeII/H-beta ratios that rule out hard AGN spectra via Cloudy modeling.
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Little Red Dots as Supermassive Analogs of SS 433
LRDs are interpreted as high-inclination hyper-Eddington accreting SMBHs analogous to SS 433, with V-shaped SEDs, X-ray weakness, and Balmer breaks emerging from disk self-shielding geometry.
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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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The UV Side of Little Red Dots: Red, Compact, and Iron-Enhanced Rest-UV Emission with a Strong Downturn around Ly$\alpha$
Analysis of ~100 JWST LRDs finds redder, compact UV emission with Fe II/Mg II ~8-10 and correlations suggesting central red continuum (β_UV~0) beyond host galaxy contribution.
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Why Little Red Dots Disappear at z < 3: Evolution of Number Density and Halo Mass
LRDs transition from underdense low-halo-mass environments at z>4 to typical galaxy conditions by z~3.5, with halo growth leading to larger sizes and SED changes that explain their disappearance at lower redshifts.
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Connecting the Dots: UV-Bright Companions of Little Red Dots as Lyman-Werner Sources Enabling Direct Collapse Black Hole Formation
UV-bright companions to Little Red Dots provide Lyman-Werner fluxes of J21 ~ 10^2.5-10^5 that can suppress H2 cooling and enable direct collapse to massive black holes.
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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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Between Degeneracy and Evolution: UV-to-optical Insights into the BH$^*$ Model in Little Red Dots
Bayesian continuum fitting of 66 LRDs shows the BH* model fits ~6% best, rising to ~40% under AGN-disfavoring priors, with most objects stellar/AGN-dominated and possible evolutionary trends.
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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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Strong X-ray Variability of I Zwicky 1: Obscuration from Clumpy Accretion-Disk Winds
Variable column density and covering factor of three ionized absorbers in clumpy disk winds explain the X-ray variability in I Zw 1 with stable corona.
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Blackbody Quasar and Radio Source (BBQSORS): A Candidate of Transitional Little Red Dots with a $T\sim10^4\ K$ Blackbody Spectrum
A z=1.715 radio-loud quasar exhibits a ~10,000 K blackbody UV continuum and three-component blackbody photometry, marking it as a candidate transitional Little Red Dot.
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The X-ray-to-UV relation does not evolve in homogeneous quasar samples
A bias-controlled quasar sample of ~2000 objects demonstrates that the X-ray-to-UV luminosity relation remains constant from redshift 0.7 to 5.
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Mass and Spin Growth of Very Massive Stars in Star Clusters Potentially Associated with Little Red Dots
Simulations show VMS in star clusters reach 10^3-10^4 solar masses with dimensionless spins >10 under bloated accretion conditions, potentially forming spinning IMBHs that produce GW bursts like GW190521.
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Non-LTE atmosphere models of very luminous sources and their applicability to Little Red Dots, quasi-stars, and similar objects
Non-LTE wind atmosphere models computed with CMFGEN reproduce the SED and Balmer decrement of most Little Red Dots when dust-attenuated with Av ~2, while predicting Fe II, O I, and Ca lines, but struggle to produce both a genuine Balmer break and strong lines simultaneously.
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Unveil the nature of JWST-AGN and Little Red Dots with SKAO continuum surveys
SKAO continuum surveys will detect radio emission from JWST AGN and LRDs and distinguish between Compton-thick absorption, intrinsically weak accretion, and dense gas cocoon scenarios.