Astrophysics Seminars

Telltale signs of quiescent black holes include sharp spikes in the galaxy's light profile and the presence of stars that are moving anomalously fast near the galaxy's center. A black hole captures all stars within a critical radius, and a star that...

ABSTRACT: Quasi-Periodic Oscillations (QPOs) have been measured in the tails of 2 out of 3 SGR giant flares. An attractive explanation for these QPOs is that they are due to torsional oscillations of the magnetar driving the flare. This opens up a...

I will present a novel screening mechanism that allows a scalar field to mediate a long range ~Mpc force of gravitational strength in the cosmos while satisfying local tests of gravity. The mechanism hinges on local symmetry restoration in the...

ABSTRACT: Pulsars are electromagnetic machines that convert the rotational energy of neutron stars into relativistic magnetically-dominated outflows. How these machines actually operate has remained a puzzle for many years. I will describe the...