JWST/MIRI detects [Ne V] 14.3 micron emission from O-star winds in 5 of 22 observed stars, enabling wind speed and mass-loss rate estimates even in weak-wind regimes.
Merging binary black holes formed through chemically homogeneous evolution in short-period stellar binaries
10 Pith papers cite this work. Polarity classification is still indexing.
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abstract
We explore a newly proposed channel to create binary black holes of stellar origin. This scenario applies to massive, tight binaries where mixing induced by rotation and tides transports the products of hydrogen burning throughout the stellar envelopes. This slowly enriches the entire star with helium, preventing the build-up of an internal chemical gradient. The stars remain compact as they evolve nearly chemically homogeneously, eventually forming two black holes, which, we estimate, typically merge 4--11 Gyr after formation. Like other proposed channels, this evolutionary pathway suffers from significant theoretical uncertainties, but could be constrained in the near future by data from advanced ground-based gravitational-wave detectors. We perform Monte Carlo simulations of the expected merger rate over cosmic time to explore the implications and uncertainties. Our default model for this channel yields a local binary black hole merger rate of about $10$ Gpc$^{-3}$ yr$^{-1}$ at redshift $z=0$, peaking at twice this rate at $z=0.5$. This means that this channel is competitive, in terms of expected rates, with the conventional formation scenarios that involve a common-envelope phase during isolated binary evolution or dynamical interaction in a dense cluster. The events from this channel may be distinguished by the preference for nearly equal-mass components and high masses, with typical total masses between 50 and 110 $\textrm{M}_\odot$. Unlike the conventional isolated binary evolution scenario that involves shrinkage of the orbit during a common-envelope phase, short time delays are unlikely for this channel, implying that we do not expect mergers at high redshift.
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Presents a grid of 113 fast-rotating, chemically-homogeneous massive star models at Z=0.001 reaching core collapse with high angular momentum for use as supernova and GRB progenitors.
Bayesian inference on LVK O1-O3 events with eccentric aligned-spin waveforms yields log10 Bayes factors of 1.77-4.75 favoring eccentricity for GW200129, GW190701 and GW200208_22, and >99.5% probability that at least one of 57 events is eccentric under an astrophysically motivated rate prior.
Maximum-likelihood-based posterior predictive checks detect model misspecification better than event-level versions for uncertain spin tilts, but current detector sensitivity limits their power; the Gaussian Component Spins model underpredicts high spin magnitudes and overpredicts anti-aligned tilts
Spin sorting with the default spin model distinguishes spinning and nonspinning binary black hole populations in simulations and shows real data rule out a fully nonspinning population but allow mixed ones with up to 80% nonspinning sources.
Simulations with a new tidal model in COMPAS predict that merging binary black holes from isolated evolution are strongly biased to low effective spins, with one third below 0.05 and only 3% above 0.5, but the high-spin fraction rises to 15% at higher redshifts.
Binary evolution modeling constrains donor masses of 14-23 solar masses for two luminous red novae and shows dust masses are 1-5 orders of magnitude below total ejected envelope masses.
GWTC-2.1 adds eight new high-significance compact binary coalescence events to the prior catalog, extending the observed black hole mass range and including candidates inside the pair-instability mass gap.
GWTC-3 catalogs 90 compact binary coalescence events with p_astro > 0.5 from LIGO and Virgo's first three observing runs, including the first confident neutron star-black hole binaries.
Theoretical predictions for local BBH merger rates exceed observations by a factor >10 under conservative SFRD and metallicity assumptions, indicating need for revisions in stellar evolution.
citing papers explorer
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GWTC-2.1: Deep Extended Catalog of Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run
GWTC-2.1 adds eight new high-significance compact binary coalescence events to the prior catalog, extending the observed black hole mass range and including candidates inside the pair-instability mass gap.
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GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run
GWTC-3 catalogs 90 compact binary coalescence events with p_astro > 0.5 from LIGO and Virgo's first three observing runs, including the first confident neutron star-black hole binaries.