Astrophysics Seminars

ABSTRACT: Methane creates a volatile cycle on Titan akin to the Earth's hydrologic cycle. But why does methane continue to do so after 4.5 billion years of geologic time when it is so unstable against photolysis? I will show how a variety of Cassini...

ABSTRACT: The first results obtained from the Baryon acoustic Oscillation Spectroscopic Survey in SDSS-III on large-scale structure using the Lyman alpha forest will be discussed. Thanks to the unprecedentedly large numbers of quasar spectra...

ABSTRACT: Superluminous supernovae can have optical luminosities hundreds of times larger than normal events. I argue that most of these are the result of interaction with dense circumstellar matter and can be viewed as shock breakout in a dense...

ABSTRACT: Dynamical tides, involving the excitation and dissipation of waves and oscillation modes, play an important role in many different binary systems. I will discuss recent works on dynamical tides in three types of systems: (i) Compact...

ABSTRACT: Can we use the Fermi satellite like WMAP? In 2006, S. Ando and I proposed to use anisotropies in the gamma-ray background (not CMB!) as a smoking-gun signature of annihilation of dark matter particles in the universe. The idea is simple...

ABSTRACT: New physics at the electro-weak scale might unlock the mysteries of the generation of the (baryonic) matter-antimatter asymmetry and of the particle nature of dark matter. I will review recent progress on understanding baryogenesis at the...

ABSTRACT: A massive black hole sits in the heart of the Milky Way. One consequence of the black hole is that it ejects "hypervelocity stars" from the Milky Way at ~1000 km/s velocities. We discovered the first hypervelocity star in 2005, and...

ABSTRACT: In the supersymmetric framework, a higgsino asymmetry exists in the universe before the electroweak phase transition. We investigate whether the higgsino is a viable asymmetric dark matter candidate. We find that this is indeed possible...