Spectra of kilonovae, radioactively-powered electromagnetic radiation from neutron star mergers, provide us with information of r-process nucleosynthesis. In the photospheric phase, which photons diffuse out from optically thick matter, absorption features in the spectra can be used to identify individual elements. However, the decode of the spectra for the first detected kilonova...
Neutron star mergers are believed to be a major cosmological source of rapid neutron-capture elements, but only limited definite spectral identifiers of these heavy elements have been found. Identifying P$\,$Cygni lines are important because they provide significant information not just potentially on the elemental composition of the merger ejecta, but also on the velocity, geometry, and...
The production of elements heavier than iron in the Universe still remains an unsolved mystery. About half of them are thought to be notably produced by the astrophysical r-process (rapid neutron-capture process) [1], for which one of the most promising production sites are neutron star mergers (NSM) [2]. In August 2017, gravitational waves generated by a NSM event were detected by the LIGO...
The spectroscopic data obtained for AT2017gfo remain the only spectral observations of a kilonova event. These data, despite being obtained ~6 years ago, are still not fully understood, and still contain a number of unexplored features. Composition studies investigating the abundance of the synthesised r-process material have proven challenging to undertake. Proposed identifications of...
