This series consists of talks in areas where gravity is the main driver behind interesting or peculiar phenomena, from astrophysics to gravity in higher dimensions.
The bimodality of gamma-ray burst (GRB) durations points
to distinct progenitor classes for the long- and short-duration GRBs. While the
progenitors of long-duration GRBs are now known to be massive stars, the
progenitors of short-duration GRBs remain unidentified. In this talk I will
discuss the discovery of short GRB afterglow and their host galaxies, detailed
studies of their environments from parsec to galactic scales, and studies of
their energetics and beaming. Taken together, these observations point to the
The relativistic wind of pulsars consists of toroidal
stripes of opposite magnetic field polarity, separated by current sheets of hot
plasma. By means of 2D and 3D particle-in-cell simulations, we investigate
particle acceleration and magnetic field dissipation at the termination shock
of a striped pulsar wind. At the shock, the flow compresses and the alternating
fields annihilate by driven magnetic reconnection. Irrespective of the stripe
wavelength "lambda" or the wind magnetization "sigma" (in
The majority of work on asymptotically anti-de Sitter
spacetimes, much of it motivated by the AdS/CFT correspondence, assumes
configurations which are either at or close to equilibrium.
Neutron stars possess the strongest gravitational fields
among stellar objects in the Universe that are not surrounded by a horizon.
This causes the emission from their surfaces to be strongly lensed and
deformed. Two upcoming space X-ray missions, ESA's LOFT and NASA's NICER, aim
to use observations of lightcurves from spinning neutron stars to map their
gravitational fields as well as measure their masses and radii. In this talk, I
will discuss some unexpected strong-field phenomena that affect gravitational
Gamma Rays at 130 GeV and How They Might Come from Dark
Matter"
I'll discuss the exciting (but somewhat controversial)
new discovery of a sharp gamma ray feature at 130 GeV from near the galactic
center and review some other evidence that might link it to annihilation of
dark matter. I will then explain the challenges in understanding how dark
matter might produce this signal and explain a model or two that overcome these
difficulties.
In the context of holography applied to condensed matter
theory, I will present an analysis of transport properties of p-wave
superfluids by means of a gravity dual. Fluctuations modes in the SU(2)
Einstein-Yang-Mills theory are considered, and phenomenological implications
are derived. Due to the spatial anisotropy of the system, a non-universal shear
viscosity is obtained, along with a new coefficient associated to normal stress
differences. I will also discuss how the transport phenomena in this model is
Pulsars are rotating magnetized neutron stars that emit
broadband pulses of radiation. Our ability to model magnetospheres of pulsars has been hampered by the difficulty of solving the self-consistent behavior of strongly magnetized relativistic plasmas. I will describe
recent progress in numerical modeling of magnetically-dominated plasmas and show applications to pulsar magnetospheres in increasing levels of realism, including ideal and resistive force-free,
Millisecond
spin-period radio pulsars provide us with unique astronomical
"laboratories" for exploring fundamental physics in a variety of ways
-- from the physics of matter at super-nuclear density, to experimental tests
of gravity. They have also provided the only experimental evidence so far for
the existence of gravitational waves (GW). A set of millisecond pulsars
acting as precise astronomical clocks may also be used as a direct GW detector,
sensitive to the nanohertz-frequency GW expected to be emitted by supermassive
In this talk I will first review static black holes in
Kaluza-Klein theory. It is well-known that within this theory there exist black
strings which are non-uniform along the Kaluza-Klein circle. Using numerical
methods, I will explain how to construct (for the first time) non-uniform black
strings in D>10, where D is the total number of spacetime dimensions. The
stability of such black objects has not been discussed before, and in the last
part of the talk I will explain how one can study the stability of non-uniform