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.
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
I will discuss recent work in simulating asymptotically
anti-de Sitter spacetimes, and its relation to heavy ion collider physics. For
this purpose, I intend to focus on a class of oblately deformed black hole
spacetime solutions. For each of these solutions, I will map the gravitational
metric in the spacetime bulk to a stress tensor one-point function of the
conformal field theory defined on the spacetime boundary. During the ring-down
process, wherein the deformed black hole settles down to the AdS analog of the
We study the gravitational collapse of the axion-dilaton
system suggested by type IIB string theory in dimensions ranging from four to
ten.
We extend previous analysis concerning the role played by
the global SL(2,
R) symmetry and also we explain ,why we do have three
different assumptions(cases). We evaluate the Choptuik exponents in the
elliptic case.
Eventually we try to explain some of the open
questions for two other assumptions and future directions.