IPMU Colloquium

Speaker: Kinwah Wu (University College London (UCL))
Title: Covariant transport of radiation and particles and applications in extremely strong gravity environments and in cosmology
Date (JST): Wed, Jan 10, 2024, 15:30 - 17:00
Place: Lecture Hall
Abstract: Correct interpretation of observations relies on proper modelling of the astrophysical systems and proper treatment of the radiation from the systems it is generated and of how the radiation is modified when it propagates to the observer. With the high quality spectroscopic and timing data, in photonic and non-phontonic particles, to be obtained by new generation of observatories and experiments, a proper treatment of the transport processes is required. I will present a covariant formulation of the transport of both photonic and non-photonic particles and discuss the physics and astrophysics rationales behind it. A main objective of constructing the covariant formulation is for practical applications in real situations, in particular, in extremely strong gravity environments and in cosmology. I will show results from calculations with the covariant transport in three cases: (1) eruptive magnetic X-ray flares from near a black-hole event horizon,
(2) 21-cm line signals from the cosmological reionisation epoch, and (3) bombardment of accretion torus by energetic particles generated from the vicinity of a black hole. I will also briefly discuss the implications of this study on cosmic magnetism, timing of millisecond pulsars in extreme-mass-ratio inspirals/binaries, and radiative transport of multi-messenger signals from gravitational sources, such as neutron star - neutron star mergers.
Remarks: Lecture Hall + Zoom