## Date:

## Location:

__Shahar Hadar__

Max Planck Institute for Gravitational Physics

"Exact Gravitational Wave Signatures from Colliding Extreme Black Holes"

__Abstract__:

The low-energy dynamics of any system admitting a continuum of static configurations is approximated by slow motion in moduli (configuration) space. In the talk I will describe how this moduli space approximation can be utilized to study collisions of two maximally charged Reissner–Nordstrom black holes of arbitrary masses, and to compute analytically the gravitational radiation generated by their scattering or coalescence. Notably, the motion remains slow even though the fields are strong, and the leading radiation is quadrupolar. A simple expression for the gravitational waveform will be presented and compared at early and late times to expectations.

__Yurij Baryshev__

Saint-Petersburg State University

"Feynman's field-theoretical approach to gravitation: Consequences for relativistic astrophysics"

__Abstract:__

In view of the 100th birthday of Richard Feynman, his contribution to the gravitation theory and its consequences for relativistic astrophysics is discussed (detailed comparison with General Relativity Theory see arXiv:1702.02020). In Feynman’s Caltech “Lectures on Gravitation” a Field Approach to Gravitation (FGT – Field Gravitation Theory) is defined as the relativistic quantum theory of the second rank symmetric tensor field in Minkowski space. The crucial point of FGT is that the symmetric tensor f_ik actually contains the direct sum of three irreducible representations**: ** pure tensor + vector + scalar (trace of f_ik) in 4-dimensional Minkowski space. Conservation laws (and corresponding gauge invariance) delete four components (4-vector) in the source (T_ik) of the field and leave only traceless tensor spin-2 field and spin-0 real (not a “ghost”) field. Testable predictions of the FGT are possible detection of the scalar GW by LIGO-Virgo antennas and the structure of the EHT image of SgrA* containing horizonless compact object having size about R_g = GM/c^2 (probably pulsating) together with its own magnetic field plus jet, and accretion disk.

Note: To see the slides parallel with Professor Baryshev speaking, please go to: https://cloud.mail.ru/public/49Gg/VVbH8VU8a

__Max Riegler__

University of Brussels

"Warped Black Holes in Lower-Spin Gravity"

Abstract

In this talk, I will talk about recent work (1801.07263) showing

that (spacelike) warped AdS_3 black hole solutions can be consistently

described in a lower-spin gravity theory. This model provides a very

simple playground to explore warped black holes and at the same time

warped conformal field theories at finite temperature. I will put an

emphasis on the basic ideas that are needed to translate geometric

statements into a gauge-theoretic language as well as how to compute the

thermodynamic properties of warped black holes in this theory.