### Conveners

#### 01 - Numerical relativity

- Thomas Baumgarte (Bowdoin College)

#### 01 - Numerical relativity

- Thomas Baumgarte (Bowdoin College)

Masaru Shibata
(Kyoto University)

17/12/2015, 14:00

Talk

The merger of binary neutron stars is one of the most promising gravitational wave sources. For the detection of gravitational waves, numerical relativists are required to accurately predict gravitational waveforms and possible electromagnetic signals. I will talk on our latests effort for the numerical-relativity simulations: magnetohydrodynamics and radiation hydrodynamics simulations.

Mr
Takumu Kawamura
(University of Trento)

17/12/2015, 14:42

Talk

In this talk I will present some general relativistic magnetohydrodynamic simulations produced with the numerical code WHISKY. We have simulated magnetized binary neutron star mergers with two different Equations of State: ideal-fluid and H4. We have focused in particular on high-mass systems (both equal and unequal-mass ones) that produce after the merger a spinning black hole surrounded by a...

Wolfgang Kastaun
(Trento University)

17/12/2015, 15:03

Talk

A large number of publications model hyper-massive neutron stars (i.e. neutron stars with total mass exceeding the maximum allowed for a uniformly rotating star) produced in binary neutron star mergers by assuming a rotation profile with a rapidly rotating core. We confront such models with results of general relativistic hydrodynamic simulations which exhibit a slowly rotating core instead....

Charalampos Markakis
(University of Southampton)

17/12/2015, 15:24

Talk

Gravitational waves from neutron-star and black-hole binaries carry valuable information on their physical properties and probe physics inaccessible to the laboratory. Neutron stars can be well-modelled as simple barotropic fluids during the part of binary inspiral most relevant to gravitational wave astronomy, but the crucial geometric and mathematical consequences of this simplification have...

Alejandro Cruz Osorio
(Universidad Nacional Autónoma de México)

17/12/2015, 16:15

Talk

We present CAFE, a code designed to solve the equations of relativistic ideal magnetohydrodynamics (RMHD) in three cartesian dimensions. We present the standard tests for the relativistic RMHD regime. The tests include among the two-dimensional (2D) and 3D tests with magnetic field. The code uses high-resolution shock-capturing methods, and we present the error analysis for a combination that...

Dr
William East
(Stanford University)

17/12/2015, 16:35

Talk

A period of exponential expansion early in our cosmic history is usually
invoked to explain the large scale homogeneity and isotropy of the Universe.
However, there remain important questions about the conditions under which
inflation can actually start when homogeneity is not assumed to begin with it.
In this talk, I will present results from fully general-relativistic simulations used to...

Thomas Baumgarte
(Bowdoin College)

17/12/2015, 16:55

Talk

We study critical phenomena in the gravitational collapse of a radiation fluid. We perform numerical simulations in both spherical symmetry and axisymmetry, and observe critical scaling in both supercritical evolutions, which lead to the formation of a black hole, and subcritical evolutions, in which case the fluid disperses to infinity and leaves behind flat space. We identify the critical...

Manuel David Morales
(Instituto de Física y Matemáticas - Universidad Michoacana de San Nicolás de Hidalgo)

17/12/2015, 17:15

Talk

I present the numerical evolution of a self-gravitating massless spherical scalar field based on a new code which implements the 3+1 tetrad formulation of general relativity on compactified constant mean curvature (CMC) hypersurfaces developed by Bardeen, Sarbach and Buchman. The major advantage of this formulation is that it allow us to model with high accuracy the scalar radiation at future...

Mrs
Daniela Perez
(Instituto Argentino de Radioastronomia)

17/12/2015, 17:35

Talk

We show that a spherically symmetric gravitational collapse of a star can result in a bounce if the equation of state behaves with sufficient rigidity just before the formation of an event horizon. The relativistic time dilation produced by the strong gravity makes the whole process to be undistinguishable from a black hole on timescales shorter than the Hubble time for a distant observer. We...

Dr
Ilia Musco
(Laboratoire Univers et Théories (LUTH) - Observatoire de Paris)

17/12/2015, 17:55

Talk

In the context of gravitational collapse to form a black hole, one sees the appearance of inner and outer trapping horizons (foliated by marginally trapped surfaces), as was already noted in numerical calculations in the 1960s. This phenomenology has acquired new interest in connection with discussions of the Hayward unified first law of black hole dynamics. We have investigated the nature of...

Alberto Saa
(UNICAMP)

17/12/2015, 18:15

Poster

By exploring the numerical scheme introduce in [1], we analyze the asymptotic ($u\to\infty$) evolution of Robinson-Trautman spacetimes, with special emphasis on the behavior of the apparent horizon and its curvature anisotropies, which can indeed induce accelerations and a recoil in the remnant black hole due to asymmetrical emission of gravitational waves [2].
**References**
[1] A. Saa...