First spectroscopic variability in a z~7 LRD shows rapid changes in both narrow and broad line regions, implying direct ionization from the central source to surrounding nebular gas.
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31 Pith papers cite this work, alongside 109 external citations. Polarity classification is still indexing.
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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.
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.
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.
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.
High-resolution spectra show Balmer absorption in 4/10 LRDs with blue-shifted velocities and exponential wings, supporting a model of co-located partial-covering gas with inflow/outflow gradients.
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.
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.
JWST observations of ERQs show stratified gas kinematics via deblended optical emission lines, with UV lines dominated by scattered light and optical lines mixing scattered and obscured emission.
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.
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.
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.
Coevolving super-Eddington black holes and nuclear starbursts in high-redshift halos naturally generate the V-shaped UV-to-optical spectra and weak high-energy emission of little red dots.
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.
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.
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.
citing papers explorer
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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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Spectral Uniformity of Little Red Dots: A Natural Outcome of Coevolving Seed Black Holes and Nascent Starbursts
Coevolving super-Eddington black holes and nuclear starbursts in high-redshift halos naturally generate the V-shaped UV-to-optical spectra and weak high-energy emission of little red dots.