Relativistic transport model for beta-particles in homologously expanding kilonova ejecta, incorporating per-species atomic data, shows non-local deposition and escape lower thermalization efficiency with analytic prescriptions supplied for light-curve codes.
Impact of ejecta morphology and composition on the electromagnetic signatures of neutron star mergers
5 Pith papers cite this work. Polarity classification is still indexing.
abstract
The electromagnetic transients accompanying compact binary mergers ($\gamma$-ray bursts, afterglows and 'macronovae') are crucial to pinpoint the sky location of gravitational wave sources. Macronovae are caused by the radioactivity from freshly synthesised heavy elements, e.g. from dynamic ejecta and various types of winds. We study macronova signatures by using multi-dimensional radiative transfer calculations. We employ the radiative transfer code SuperNu and state-of-the-art LTE opacities for a few representative elements from the wind and dynamical ejecta (Cr, Pd, Se, Te, Br, Zr, Sm, Ce, Nd, U) to calculate synthetic light curves and spectra for a range of ejecta morphologies. The radioactive power of the resulting macronova is calculated with the detailed input of decay products. We assess the detection prospects for our most complex models, based on the portion of viewing angles that are sufficiently bright, at different cosmological redshifts ($z$). The brighter emission from the wind is unobscured by the lanthanides (or actinides) in some of the models, permitting non-zero detection probabilities for redshifts up to $z=0.07$. We also find the nuclear mass model and the resulting radioactive heating rate are crucial for the detectability. While for the most pessimistic heating rate (from the FRDM model) no reasonable increase in the ejecta mass or velocity, or wind mass or velocity, can possibly make the light curves agree with the observed nIR excess after GRB130603B, a more optimistic heating rate (from the Duflo-Zuker model) leads to good agreement. We conclude that future reliable macronova observations would constrain nuclear heating rates, and consequently help constrain nuclear mass models.
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A simulation-based inference method with Gaussian process emulators trained on 1300 kilonova simulations recovers parameters accurately and rapidly while avoiding MCMC biases from likelihood misspecification.
Magnetically driven shocks from neutron star merger remnants can reheat ejecta to nuclear statistical equilibrium, alter r-process yields, and produce observable changes in kilonova color and light curves.
Monte Carlo simulation of post-merger remnant shows pair annihilation rates greatly increased in cold low-density regions and inelastic electron scattering important for heavy-lepton neutrino thermalization, processes not included in prior merger simulations.
The paper proposes a high-redshift (z>2) origin for GRB 061201 by combining afterglow constraints with deep JWST near-infrared imaging of a faint candidate host.
citing papers explorer
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Beta-Particle Transport and Thermalization in Kilonova Ejecta with Detailed Atomic Microphysics
Relativistic transport model for beta-particles in homologously expanding kilonova ejecta, incorporating per-species atomic data, shows non-local deposition and escape lower thermalization efficiency with analytic prescriptions supplied for light-curve codes.
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Rapid and robust simulation-based inference for kilonovae
A simulation-based inference method with Gaussian process emulators trained on 1300 kilonova simulations recovers parameters accurately and rapidly while avoiding MCMC biases from likelihood misspecification.
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Effects of magnetically driven shocks on nucleosynthesis and kilonovae from neutron star mergers
Magnetically driven shocks from neutron star merger remnants can reheat ejecta to nuclear statistical equilibrium, alter r-process yields, and produce observable changes in kilonova color and light curves.
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Assessing the Relative Importance of Neutrino Matter Interaction Channels in Post-Merger Remnant of Binary Neutron Stars
Monte Carlo simulation of post-merger remnant shows pair annihilation rates greatly increased in cold low-density regions and inelastic electron scattering important for heavy-lepton neutrino thermalization, processes not included in prior merger simulations.
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A possible high-redshift origin for the short GRB 061201: implications of a compact binary merger beyond cosmic noon
The paper proposes a high-redshift (z>2) origin for GRB 061201 by combining afterglow constraints with deep JWST near-infrared imaging of a faint candidate host.