A quasar pair at z=5.7 is confirmed in a galaxy merger via ALMA, setting a lower limit of >1.2% on the pair fraction at 5.5<z<6 and linking it to the PTA gravitational wave background.
An ALMA [CII] survey of 27 quasars at z>5.94
11 Pith papers cite this work, alongside 298 external citations. Polarity classification is still indexing.
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abstract
We present a survey of the [CII] 158 $\mu$m line and underlying far-infrared (FIR) dust continuum emission in a sample of 27 z>6 quasars using the Atacama Large Millimeter Array (ALMA) at ~1" resolution. The [CII] line was significantly detected (at >5-sigma) in 23 sources (85%). We find typical line luminosities of $L_{\rm [CII]}=10^{9-10}$ L$_\odot$, and an average line width of ~385 km/s. The [CII]-to-far-infrared luminosity ratio ([CII]/FIR) in our sources span one order of magnitude, highlighting a variety of conditions in the star-forming medium. Four quasar host galaxies are clearly resolved in their [CII] emission on a few kpc scales. Basic estimates of the dynamical masses of the host galaxies give masses between $2\times10^{10}$ and $2\times10^{11}$ M$_\odot$, i.e., more than an order of magnitude below what is expected from local scaling relations, given the available limits on the masses of the central black holes ($>3\times10^8$ M$_\odot$, assuming Eddington-limited accretion). In stacked ALMA [CII] spectra of individual sources in our sample, we find no evidence of a deviation from a single Gaussian profile. The quasar luminosity does not strongly correlate with either the [CII] luminosity or equivalent width. This survey (with typical on-source integration times of 8 min) showcases the unparalleled sensitivity of ALMA at millimeter wavelengths, and offers a unique reference sample for the study of the first massive galaxies in the universe.
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An extended Lyα halo is detected around the z=6.64 BAL quasar J0910-0414, extending to 11 pkpc with rotation-like kinematics, lower velocity dispersion than the host core, and contributing 55% of the total Lyα flux due to central absorption.
N-body simulations demonstrate runaway GW BBH mergers in dense BH clusters (≥5×10^9 M⊙/pc³) produce ~10³ M⊙ IMBHs within 10 Myr.
ALMA survey of CO(7-6) and [C I](2-1) in 18 z~6 quasars yields molecular gas mass estimates from multiple tracers and indicates that PDR models cannot fully account for the observed excitation, pointing to additional heating processes.
ALMA observations and modeling of a z=6.52 lensed quasar indicate AGN dust heating contributes ~13% to sub-mm emission, implying mild overestimation of prior FIR-based star formation rates for high-redshift quasars.
New ALMA [C II] and FIR data on PSO J083+11 at z=6.34 reveal ordered rotation, typical star-forming ratios, and no outflow signatures in either galaxy, interpreted as a pre-AGN-feedback accretion phase.
Simulations and analytic modeling predict that the supermassive black hole to stellar mass ratio peaks at several percent around redshift 7-10 before declining toward the present day.
Synthesizes simulation predictions and pathfinder data to outline a broadband radio SED and spectral curvature strategy for identifying the earliest radio AGN with the SKA.
SHARP on ELT will enable the first mapping of z>9 Lyα nebulae at scales from 150 pc to 100 kpc.
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.
Advocates for SKA frequency coverage beyond 15 GHz to observe redshifted low-J CO, HCN and similar lines for cold molecular gas studies in high-redshift galaxies.
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