New template-fitting selection yields 241 BH*-dominated LRD candidates at z~1.7-9.3 with number density peaking at z~5-6, demonstrating persistence to lower redshifts.
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Spectral Uniformity of Little Red Dots: A Natural Outcome of Coevolving Seed Black Holes and Nascent Starbursts
14 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
The birth of seeds of massive black holes (BHs) and nascent galaxies at cosmic dawn takes place in dense gaseous environments, which play a crucial role in shaping their coevolution and radiation spectra. We investigate gas accretion during the assembly of massive halos with $M_{\rm h}\gtrsim 10^{10-11}~M_\odot$ at redshifts $z\simeq 4-10$, driving both rapid BH feeding and concurrent nuclear starbursts. As the BH grows to $\sim 10^{6-7}~M_\odot$ via super-Eddington accretion, the accretion power inflates a dense envelope whose effective temperature approaches the Hayashi limit at $T_{\rm eff}\simeq 5000~{\rm K}$, producing red optical emission, while a coeval young stellar population of $\sim 10^7~M_\odot$ provides blue UV emission. This early coevolving system naturally reproduces the characteristic spectral features of the so-called little red dots (LRDs), a population of broad-line active galactic nuclei (AGNs), including the V-shaped UV-to-optical spectra and weakness of X-ray, infrared, and radio emission. Massive stars in the nuclear starburst soon explode as supernovae, injecting energy and momentum that expel gas from the nucleus, quench gas supply to the BH envelope, and ultimately drive a transition into normal AGN phases. For individual LRDs, the optical-to-UV luminosity ratio remains nearly constant at $L_{\rm opt}/L_{\rm UV}\simeq 2-10$ from the onset of accretion bursts for $\simeq 15~{\rm Myr}$, one-third of the Salpeter time, until quenching by stellar feedback. While this ratio is sustained for the LRD population at $z\simeq 4-8$, it declines toward lower redshifts as BHs can no longer maintain red envelopes, thereby losing the LRD characteristics.
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The survey identifies 27 low-redshift LRDs with compact morphology, V-shaped continua, broad Balmer lines with extreme decrements, and ubiquitous outflows, matching high-z counterparts and yielding a number density lower limit of 7.5e-10 cMpc^-3.
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.
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.
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.
A theoretical model of a magnetized black hole envelope is developed to explain the broad emission lines and X-ray faintness observed in little red dots using co-rotating plasma clumps and limited X-ray sources.
Paschen jumps in Little Red Dots indicate their continua originate from free-bound recombination emission in low-temperature nebular gas rather than thermalized or AGN components.
FIRE-2 simulations with gravitational torque-driven and free-fall accretion models predict enough high-redshift AGN to explain little red dots, with a super-Eddington Eddington-limited scenario for M_BH >= 2e5 Msun in M_star >= 2e7 Msun galaxies reproducing key observations.
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.
LRDs require Compton-thick gas at moderate metallicity plus high accretion rates producing weak X-rays to explain their non-detection, implying they are not chemically pristine.
Half of strong CIII] emitters at z=5-7 show secure AGN signatures, with median equivalent width rising 0.67 dex relative to z=3-4 galaxies.
Rapid halo growth in SEEDZ simulations enables heavy black hole seed formation via supermassive stars at a comoving number density of 0.1 cMpc^{-3} by z=10, with most seeds in near-solar metallicity gas.
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.
citing papers explorer
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Black Hole Stars Across the Universe: Identifying Central Engine Dominated Little Red Dots at $z\sim1.5-9.5$
New template-fitting selection yields 241 BH*-dominated LRD candidates at z~1.7-9.3 with number density peaking at z~5-6, demonstrating persistence to lower redshifts.
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(LRDs)$^2$: The Low-ReDshift Little Red Dots Survey. II. DESI DR1 Sample
The survey identifies 27 low-redshift LRDs with compact morphology, V-shaped continua, broad Balmer lines with extreme decrements, and ubiquitous outflows, matching high-z counterparts and yielding a number density lower limit of 7.5e-10 cMpc^-3.
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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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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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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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A Magnetized Black Hole Envelope Model for Little Red Dots
A theoretical model of a magnetized black hole envelope is developed to explain the broad emission lines and X-ray faintness observed in little red dots using co-rotating plasma clumps and limited X-ray sources.
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Paschen Jumps in Little Red Dots: Evidence for Nebular Continua
Paschen jumps in Little Red Dots indicate their continua originate from free-bound recombination emission in low-temperature nebular gas rather than thermalized or AGN components.
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Little Red Dots on FIRE: The Ability of Bursty Galaxies to Host an Abundant Population of High-Redshift AGN
FIRE-2 simulations with gravitational torque-driven and free-fall accretion models predict enough high-redshift AGN to explain little red dots, with a super-Eddington Eddington-limited scenario for M_BH >= 2e5 Msun in M_star >= 2e7 Msun galaxies reproducing key observations.
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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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On the quenching of LRD X-ray emission by both Compton-thick gas and high accretion rates
LRDs require Compton-thick gas at moderate metallicity plus high accretion rates producing weak X-rays to explain their non-detection, implying they are not chemically pristine.
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The AGN nature of strong CIII emitters in the Early Universe with JWST
Half of strong CIII] emitters at z=5-7 show secure AGN signatures, with median equivalent width rising 0.67 dex relative to z=3-4 galaxies.
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SEEDZ: Rapid Galaxy Assembly as a Pathway to Supermassive Stars, Dense Stellar Environments and Massive Black Hole Seeds
Rapid halo growth in SEEDZ simulations enables heavy black hole seed formation via supermassive stars at a comoving number density of 0.1 cMpc^{-3} by z=10, with most seeds in near-solar metallicity gas.
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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.