Wednesday Colloquium


"Newtonian dark energy versus Einsteinian structure formation"

Boud Roukema (Astronomy Center, Nicolaus Copernicus University, Toruń)

By definition, the standard, homogeneous models of the Universe are likely to fail when the Universe is inhomogeneous. The virialisation fraction measures inhomogeneity. Its redshift evolution roughly matches the evolution of would-be "dark energy", if the "dark energy" is inferred from the observations by assuming a homogeneous model. This suggests that "dark energy" is a Newtonian misinterpretation of the fact that we live in the inhomogeneous epoch of the Universe. A virialisation-induced approximation based on the general-relativistic, scalar-averaging approach to defining cosmological parameters will be presented as a physically motivated, dark-energy-free approach to modelling extragalactic observations.


"Contributions from jets and accretion to broad-band spectra of black-hole binaries"

Andrzej Zdziarski (CAMK, Warsaw)


"Modelling relativistic stellar tidal disruptions with SPH"

Emilio Tejeda (Stockholm University )

In this talk I will present the implementation of a generalized Newtonian potential for capturing general relativistic features of Schwarzschild spacetime within a smoothed particle hydrodynamics (SPH) code (arXiv:1303.4068). Then I will show the use of this code for studying GR effects on the tidal disruption of a solar-type star by a supermassive black hole.