The Radiative Transfer and Atomic Physics of Kilonovae

Session

Wednesday morning

6 Sept 2023, 09:30

Wenner-Gren Center

36. An Overview of Atomic Processes for Kilonovae

Nigel Badnell (University of Strathclyde)

06/09/2023, 09:30

We will review atomic processes relevant to kilonovae and the current
state-of-play in servicing the needs of modellers.

The atomic processes relevant to kilonovae separate into their two plasma phases: the first few days, where LTE holds, and the subsequent non-LTE phase. In LTE, where fractional ionic abundances and level populations are given by the Saha--Boltzmann equations, the main...

28. Multi-component Ejecta and Time-Evolving Elemental Abundances in the GW170817 Kilonova

Nicholas Vieira (McGill University)

06/09/2023, 10:25

Contributed talk

In kilonovae, freshly-synthesized r-process elements imprint absorption features on optical spectra, as observed in AT2017gfo. These spectral features provide insights into the physical conditions of the r-process, but measuring the detailed composition of the ejecta is challenging. [Vieira et al. (2023)][1] introduced Spectroscopic r-Process Abundance Retrieval for Kilonovae (SPARK), a tool...

38. Atomic Physics of r-Process Elements

Chris Fontes (Los Alamos National Laboratory)

06/09/2023, 11:05

The atomic properties of r-process elements are predicted to play an important role in determining the electromagnetic emission from kilonovae, which result from the merger of two neutron stars. More specifically, the radiative opacity is an important quantity that determines the flow of radiation through the ejecta and wind material that result from the merger. In this talk, we discuss the...

41. Atomic calculations and radiative transfer simulations for modelling kilonova

Smaranika Banerjee (Stockholm University)

06/09/2023, 12:00

19. Analytic Description of Beta Decay e$^\pm$ Thermalization in Kilonovae Ejecta

Ben Shenhar (Weizmann Institute of Science)

06/09/2023, 12:20

Contributed talk

Kilonovae light-curves depend on the efficiency with which beta decay e$^\pm$ deposit their energy in the expanding ejecta. We show that the time $t_{\rm e}$, at which the deposited energy fraction drops to $1/e$, depends mainly on ejecta density and velocity, and only weakly on the initial electron fraction $Y_e$ and entropy $s_0$: $t_{\rm e} = t_0 \times (\rho t^3/(\rho t^3)_0)^{s_{\rm e}}$...