RESCEU Summer School 2023

Abstract:

Accretion is a ubiquitous phenomenon in the universe, with accretion onto black holes representing one of the most efficient energy conversion processes. Given the extreme gravitational environment of black holes, these accretion processes can drive a variety of high-energy phenomena. Notably, hot coronae surrounding the accretion disk have recently been discussed as potential high-energy neutrino production sites, which might dominate the neutrino sky. In this lecture, I will provide an overview of the accretion processes onto black holes and discuss recent theoretical and observational progress in black hole corona studies, including neutrino production processes. Moreover, I will explain how black hole accretion can constrain the abundance of primordial black holes in the universe.

Abstract:

First, I will give an introduction to various topological solitons and defects. I then discuss how they are related through composite solitons, based on [1]. Such composite solitons attract attentions in condensed matter physics and QCD. Finally, among them, I will show particularly interesting example in QCD: domain-wall Skyrmions, composites of domain walls and Skyrmions, appearing in the ground state of QCD at finite density with strong magnetic field [2].

[1] Muneto Nitta, Phys.Rev.D 105 (2022) 10, 105006, 2202.03929 [hep-th]

[2] Minoru Eto, Kentaro Nishimura, Muneto Nitta, 2304.02940 [hep-ph]

Abstract

Source modeling and single-event inference:

I will introduce some of the theoretical framework of gravitational-wave astronomy and neutron-star astrophysics, focusing on fundamental energetics, source modeling, and the imprint of matter. I will show how the properties of dense matter link through the properties of isolated stars to those of a merging binary.  I will describe the process of inferring the properties of a source system using gravitational waves, and discuss some ways we can characterize and marginalize over statistical and systematic uncertainties when interpreting gravitational-wave observational data.

Population results and future expectations:

The most recent LIGO-Virgo-Kagra catalog, GWTC-3, identified 90 merging binaries, which range from a double neutron star with a total mass of 2.7 at 40 Mpc (GW170817) to a double black hole with a total mass of 150 at 5.3 Gpc (GW190521). Collectively, gravitational-wave observations have many potential implications for neutron-star astrophysics: they tell us the event rates of compact mergers, the preferred masses and spins of the source populations, and the potential imprint of a common neutron-star equation of state. I will outline how these constraints are derived, show some current results, and discuss how next-generation facilities aim to extend the reach of gravitational-wave astronomy across the observable universe.

Abstract

Theory & Modelling: 

- The interstellar medium: ionized gas, photodissociation regions, molecular gas & dust

- Radiative transfer and photoionization modelling in the first galaxies - Cosmological zoom-in simulations of galaxies in the EoR

Observations:

- The ionized gas as probed by ALMA & JWST

- The cold neutral and molecular gas as probed by ALMA

- Gathering clues on the dust content using ALMA & JWST