The critical role of nuclear heating rates, thermalization efficiencies and opacities for kilonova modelling and parameter inference

Abstract

We present an improved version of the 3D Monte Carlo radiative transfer code POSSIS to model kilonovae from neutron star mergers, wherein nuclear heating rates, thermalization efficiencies and wavelength-dependent opacities depend on local properties of the ejecta and time. Using an axially-symmetric two-component ejecta model, we explore how simplistic assumptions on heating rates, thermalization efficiencies and opacities often found in the literature affect kilonova spectra and light curves. Specifically, we compute five models: one ($\text{FIDUCIAL}$) with an appropriate treatment of these three quantities, one ($\text{SIMPLE-HEAT}$) with uniform heating rates throughout the ejecta, one ($\text{SIMPLE-THERM}$) with a constant and uniform thermalization efficiency, one ($\text{SIMPLE-OPAC}$) with grey opacities and one ($\text{SIMPLE-ALL}$) with all these three simplistic assumptions combined. We find that deviations from the $\text{FIDUCIAL}$ model are of several ($\sim 1-10$) magnitudes and are generally larger for the $\text{SIMPLE-OPAC}$ and $\text{SIMPLE-ALL}$ compared to the $\text{SIMPLE-THERM}$ and $\text{SIMPLE-HEAT}$ models. The discrepancies generally increase from a face-on to an edge-on view of the system, from early to late epochs and from infrared to ultraviolet/optical wavelengths. Our work indicates that kilonova studies using either of these simplistic assumptions ought to be treated with caution and that appropriate systematic uncertainties ought to be added to kilonova light curves when performing inference on ejecta parameters.

13 pages, 11 figures, 1 table; accepted for publication in MNRAS; added missing citations

References in corpus (55)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Multi-messenger Observations of a Binary Neutron Star Merger
• Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
• An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A
• Origin of the heavy elements in binary neutron-star mergers from a gravitational wave event
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. II. UV, Optical, and Near-IR Light Curves and Comparison to Kilonova Models
• Spectroscopic identification of r-process nucleosynthesis in a double neutron star merger
• INTEGRAL Detection of the First Prompt Gamma-Ray Signal Coincident with the Gravitational Wave Event GW170817
• The X-ray counterpart to the gravitational wave event GW 170817
• A kilonova as the electromagnetic counterpart to a gravitational-wave source
• Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis
• Illuminating Gravitational Waves: A Concordant Picture of Photons from a Neutron Star Merger
• The Emergence of a Lanthanide-Rich Kilonova Following the Merger of Two Neutron Stars
• Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. I. Dark Energy Camera Discovery of the Optical Counterpart
• Swift and NuSTAR observations of GW170817: detection of a blue kilonova
• The Combined Ultraviolet, Optical, and Near-Infrared Light Curves of the Kilonova Associated with the Binary Neutron Star Merger GW170817: Unified Data Set, Analytic Models, and Physical Implications
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South
• Magnetorotationally driven Supernovae as the origin of early galaxy $r$-process elements?
• A Radio Counterpart to a Neutron Star Merger
• Identification of strontium in the merger of two neutron stars
• Kilonovae
• The discovery of the electromagnetic counterpart of GW170817: kilonova AT 2017gfo/DLT17ck
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. V. Rising X-ray Emission from an Off-Axis Jet
• Kilonova from post-merger ejecta as an optical and near-infrared counterpart of GW170817
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-Time Emission from the Kilonova Ejecta
• Kilonova Light Curves from the Disk Wind Outflows of Compact Object Mergers
• AT2017gfo: an anisotropic and three-component kilonova counterpart of GW170817
• A Deep Chandra X-ray Study of Neutron Star Coalescence GW170817
• Follow up of GW170817 and its electromagnetic counterpart by Australian-led observing programs
• J-GEM observations of an electromagnetic counterpart to the neutron star merger GW170817
• Properties of Kilonovae from Dynamical and Post-Merger Ejecta of Neutron Star Mergers
• The Rapid Reddening and Featureless Optical Spectra of the optical counterpart of GW170817, AT 2017gfo, During the First Four Days
• Numerical Relativity Simulations of the Neutron Star Merger GW170817: Long-Term Remnant Evolutions, Winds, Remnant Disks, and Nucleosynthesis
• Sub-radian-accuracy gravitational waveforms of coalescing binary neutron stars in numerical relativity
• Axisymmetric Radiative Transfer Models of Kilonovae
• Optical follow-up of the neutron star-black hole mergers S200105ae and S200115j
• Kilonovae across the nuclear physics landscape: The impact of nuclear physics uncertainties on r-process-powered emission
• Modeling Kilonova Light Curves: Dependence on Nuclear Inputs
• AT2017gfo: Bayesian inference and model selection of multi-component kilonovae and constraints on the neutron star equation of state
• Tight multi-messenger constraints on the neutron star equation of state from GW170817 and a forward model for kilonova light curve synthesis
• Spectropolarimetry of superluminous supernovae: insight into their geometry
• Evidence for X-ray Emission in Excess to the Jet Afterglow Decay 3.5 yrs After the Binary Neutron Star Merger GW 170817: A New Emission Component
• Signatures of r-process elements in kilonova spectra
• Simulations of early kilonova emission from neutron star mergers
• Polarisation spectral synthesis for Type Ia supernova explosion models
• Inclination Dependence of Kilonova Light Curves from Globally Aspherical Geometries
• NLTE Effects on Kilonova Expansion Opacities
• Opacity of the highly ionized lanthanides and the effect on the early kilonova
• Dynamical ejecta of neutron star mergers with nucleonic weak processes II: Kilonova emission
• Actinide opacities for modeling the spectra and light curves of kilonovae
• GW170817 4.5 years after merger: Dynamical ejecta afterglow constraints
• Polarized kilonovae from black hole-neutron star mergers
• Interpolating Detailed Simulations of Kilonovae: Adaptive Learning and Parameter Inference Applications
• Hubble constant and nuclear equation of state from kilonova spectro-photometric light curves

Cited by in corpus (35)

• A data science platform to enable time-domain astronomy
• An updated nuclear-physics and multi-messenger astrophysics framework for binary neutron star mergers
• Updated observing scenarios and multi-messenger implications for the International Gravitational-wave Network's O4 and O5
• Self-consistent 3D radiative transfer for kilonovae: directional spectra from merger simulations
• NLTE Spectra of Kilonovae
• Bayesian inference of multimessenger astrophysical data: Joint and coherent inference of gravitational waves and kilonovae
• Modelling Populations of Kilonovae
• General-Relativistic Hydrodynamics Simulation of a Neutron Star - Sub-Solar-Mass Black Hole Merger
• Surrogate light curve models for kilonovae with comprehensive wind ejecta outflows and parameter estimation for AT2017gfo
• Bayesian model selection for GRB 211211A through multi-wavelength analyses
• Impact of nuclear matter properties on the nucleosynthesis and the kilonova from binary neutron star merger ejecta
• The puzzling long GRB 191019A: Evidence for Kilonova Light
• Actinide signatures in low electron fraction kilonova ejecta
• Cautionary tales on heating-rate prescriptions in kilonovae
• Kilonova constraints for the LIGO/Virgo/KAGRA neutron star merger candidate S250206dm: GW-MMADS observations
• Impact of jets on kilonova photometric and polarimetric emission from binary neutron star mergers
• The thermalization of $\gamma$-rays in radioactive expanding ejecta: A simple model and its application for Kilonovae and Ia SNe
• KilonovAE: Exploring Kilonova Spectral Features with Autoencoders
• XKN: a Semi-analytic Framework for the Modelling of Kilonovae
• IIb or not IIb: A Catalog of ZTF Kilonova Imposters
• WINTER on S250206dm: A near-infrared search for an electromagnetic counterpart to a gravitational-wave event
• Data-driven approach for modeling the temporal and spectral evolution of kilonova systematic uncertainties
• Spectral synthesis techniques for supernovae and kilonovae
• Interpolated kilonova spectra models: necessity for a phenomenological, blue component in the fitting of AT2017gfo spectra
• Simulating Binary Neutron Star Mergers with Finite-temperature Equations of State: The influences of the slope of the symmetry energy and artificial heating
• What to expect: kilonova light curve predictions via equation of state marginalization
• Kilonova-Targeting Lightcurve Classification for Wide Field Survey Telescope
• Multi-messengers from the radioactive decay of $r$-process nuclei
• Light Travel Time Effects in Kilonova Models
• Kilonova and progenitor properties of merger-driven gamma-ray bursts
• Challenging a binary neutron star merger interpretation of GW230529
• Kilonova Light Curve Parameter Estimation Using Likelihood-Free Inference
• Illuminating the Mass Gap Through Deep Optical Constraint on a Neutron Star Merger Candidate S250206dm
• Toward a Unified Understanding of the Dense Matter Equation of State
• Optimising the observation of optical kilonovae with medium size telescopes