Luminosity predictions for the first three ionisation stages of W, Pt and Au to probe potential sources of emission in kilonova
arXiv:2411.16476 · doi:10.1093/mnras/staf283
Abstract
A large number of R-matrix calculations of electron impact excitation for heavy elements (Z > 70) have been performed in recent years for applications in fusion and astrophysics research. With the expanding interest in heavy ions due to kilonova (KN) events such as AT2017gfo and AT2023vfi, this new data can be utilised for the diagnosis and study of observed KN spectra. In this work recently computed electron-impact excitation effective collision strengths are used, for the first three ionisation stages of tungsten (W, Z = 74), platinum (Pt, Z = 78) and gold (Au, Z = 79), to construct basic collisional radiative models tailored for the late stage nebular phases of KN. Line luminosities are calculated at a range of electron temperatures and densities and the strengths of these lines for a representative ion mass are compared. For the case of W III, these optically thin intensities are additionally used to constrain the mass of this ion in both AT2017gfo and AT2023vfi. Comparing with theoretical predictions of nucleosynthesis yields from neutron-star merger simulations, broad agreement with the inferred ion masses of W is found. Furthermore, we highlight the value of W measurements by showing that the abundance of other groups of elements and outflow properties are constrained by exploiting theoretically motivated correlations between the abundance of W and that of lanthanides or third r-process peak elements. Based on simple estimates, we also show that constraints on the distribution of tungsten in the ejecta may be accessible through the line shape, which may also yield information on the neutron-star merger remnant evolution.
Accepted Manuscript
References in corpus (16)
- Spectroscopic identification of r-process nucleosynthesis in a double neutron star merger
- A kilonova as the electromagnetic counterpart to a gravitational-wave source
- Further explorations of Skyrme-Hartree-Fock-Bogoliubov mass formulas. XII: Stiffness and stability of neutron-star matter
- Identification of strontium in the merger of two neutron stars
- Neutrino-driven winds from neutron star merger remnants
- JWST detection of heavy neutron capture elements in a compact object merger
- Dynamical r-process studies within the neutrino-driven wind scenario and its sensitivity to the nuclear physics input
- Spitzer Mid-Infrared Detections of Neutron Star Merger GW170817 Suggests Synthesis of the Heaviest Elements
- Post-merger Mass Ejection of Low-mass Binary Neutron Stars
- End-to-end kilonova models of neutron-star mergers with delayed black-hole formation
- Constraints on the presence of platinum and gold in the spectra of the kilonova AT2017gfo
- On the Validity of Steady-State for Nebular Phase Kilonovae
- Discovery of a 760 nm P Cygni line in AT2017gfo: Identification of yttrium in the kilonova photosphere
- Tungsten vs Selenium as a potential source of kilonova nebular emission observed by Spitzer
- New Radiative and Collisional Atomic Data for Sr {\sc ii} and Y {\sc ii} with application to Kilonova modelling
- Helium as an Indicator of the Neutron-Star Merger Remnant Lifetime and its Potential for Equation of State Constraints