Seria: Gravity and Cosmology Seminar Departament Badań Podstawowych Narodowego Centrum Badań Jądrowych

Prelegent i afiliacja: David Wiltshire (Canterbury University, New Zealand)

Data: September 11,  2024 (Wednesday),  h. 11:15

Miejsce: room 207 @Pasteura 7

Streszczenie: We present a general framework for solving Einstein's equations for stationary axisymmetric gravitationally bound differentially rotating matter distributions with internal pressure. A new quasilocal Newtonian limit is extracted for nonrelativistic relative velocities. The self-consistent coupling of quasilocal gravitational energy and angular momentum leads to a modified Poisson equation. The coupled equations of motion of the effective fluid elements are also modified, with quasilocal angular momentum and frame-dragging leading to novel dynamics. The phenonomenology of collisionless dark matter for disc galaxies is reproduced, offering an explanation for their observed rotation curves. Halos of abundant cold dark matter particles are not required.

A full class of exact solutions is found in the general case of negligible internal pressure. A new geometrical structure is found - the rotosurface - which provides a rigorous general relativity answer to the question: where is infinity? The Milky Way's rotosurface leads to new astrophysical predictions, including possible synchrotron radiation from diffuse charged particles at 500-700 kpc from the galactic centre.