Speaker 1: Koki Tokeshi

Title: Towards the resolution of uncertainty and refinement of the primordial black hole mass function

All of my researches on primordial black holes are based on the peak counting theory and its refinement version. The first subject is the window function uncertainty of the refined mass function: we have clarified that around the typical scales the additional condition for precise estimation of the PBH mass, at least under the top-hat power spectrum, has almost no effect on the abundance. Various shapes of the power spectra should also be studied as well and this is currently under consideration.
The second topic is on the spherically symmetric perturbations and the peak counting theory: the conventional formalism could not be applied for the case. This is also an ongoing subject so I will report the current status with some obtained results, but maybe without the final consequences.

Speaker 2: Naoto Kuriyama

Title: The features of mass eruptions from progenitors of Type IIn/Ibn supernovae

Some massive stars experience episodic and intense mass eruptions accompanied by fluctuations in the luminosity in the late phase of stellar evolution. Mass loss rates of such eruptions are too high to be explained by stellar wind mass loss model and thus dynamical eruptions seem to contribute to the mass loss and fluctuations in the luminosity. These mass eruptions form circumstellar matter (CSM) around the star and they could play an important role in the subsequent core-collapse supernova because the interaction between SN ejecta and CSM could be the thermal source of the SN. This kind of SNe are classified as Type IIn/Ibn SNe. However, the mechanism and energy sources which trigger these pre-SN eruptions have not been fully explained. In Kuriyama & Shigeyama (2020a), we investigate the properties of a mass eruption conducting a sudden energy injection into the stellar envelope using 1-D radiation hydrodynamical simulation code. Additionally, we recently find that the first and second mass eruptions show different features if the eruption repeats twice with an appropriate time separation, because the density structure of the stellar envelope is altered by the first eruption (Kuriyama & Shigeyama 2020b). This fact would be useful when we interpret observations which show multiple eruption events. In this presentation, we introduce the features of pre-SN mass eruptions from the progenitors of SNe IIn/Ibn.

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Last-modified: 2020-11-19 (木) 16:31:09 (154d)