DOI: 10.5281/zenodo.10635802
title: Overview of the contributions from all lanthanide elements to kilonova opacity in the temperature range from 25000 to 40000 K

description: Supplement materials of a paper submitted to Astronomy and Astrophysics entitled 'Overview of the contributions from all lanthanide elements to kilonova opacity in the temperature range from 25000 to 40000 K'.

Abstract:

Context. It is now well established that the neutron star (NS) merger is at the origin of the production of trans-iron heavy elements in the universe. These elements are therefore present in large quantities in the ejecta whose electromagnetic radiation, called kilonova is characterized by a significant opacity due to the high density of spectral lines belonging to many heavy ions. Among these, the lanthanide ions play an essential role since, with their open 4f subshell, they have a considerable number of transitions that can absorb the emitted light. The knowledge of the atomic structure and the radiative parameters of these ions as well as the determination of the corresponding opacities is therefore of paramount importance for the spectral analysis of kilonovae.Aims. The main goal of the present work is to determine the relative contributions of the different lanthanide elements to the opacity of the emission spectrum of a kilonova in its early phase, i.e., a few hours after the NS merger where the conditions are such that the temperature is between 25000 and 40000 K. At these temperatures, the lanthanide ions whose charge states are between V and VII are predominant.Methods. The pseudo-relativistic Hartree-Fock (HFR) method was used extensively to calculate the relevant atomic data (energy levels, wavelengths and oscillator strengths) in La-Lu V-VII ions. The corresponding monochromatic opacities were estimated from the expansion formalism.Results. The spectroscopic parameters were calculated for a total of more than 800 million radiative transitions in all the ions considered. These data were used to estimate the expansion opacities and Planck mean opacities for all lanthanide elements at early-phase kilonova conditions between 25000 and 40000 K, making it possible to deduce the respective contributions of each element as a function of temperature. Atomic calculations were also carried out with the fully relativistic Multiconfiguration Dirac-Hartree-Fock (MCDHF) method in the specific case of Yb V ion for which the available experimental data had not yet been compared with theoretical calculations in our previous studies on lanthanide ions.

Key words. Physical data and processes – atomic data – Kilonova explosion – opacity – neutron star mergers

Files description:

outggf_Ln_V-VII.zip folder:    45 files outggf for each lanthanide between the V and VII spectra:    first column is wavelength of the E1 transition (A),     second column is the lower energy level of the transition (1000 cm^-1)    third column is the oscillator strength

outglv_Ln_V--VII.zip folder:     45 files outglv for each lanthanide between the V and VII spectra:    first column is the energy of levels (1000 cm^-1)    second column is the total angular momentum (J-value)

readme.txt: files description