Houston, TX 77005
12:00 p.m. Wednesday, Feb. 20, 2013
On Campus | Alumni
1) Dark matter and dark energy form one of the largest gaps in our understanding of the universe. While ample evidence for both exist, we still lack a definitive theory that explains their existence. I will be giving a brief review of DM/DE, followed by a summary of a recent journal article, "Gravitational Field Equations and Theory of Dark Matter and Dark Energy" by Ma & Wang. They derive a decomposition of tensor fields and apply it to Einstein's field equations, postulating an extra term that represents the presence of dark matter and dark energy. It's a fairly well-reasoned approach, and further work may provide testable predictions.2) Magnetar AXP 1E 1547-5408 underwent a series of x-ray and gamma-ray outbursts, beginning in late 2008 detected by Swift/BAT and Fermi GBM. Subsequently renamed SGR 1550-5418 and observed by a bevy of telescopes, I report broadband phase-resolved spectral analysis of the burst and post-burst spectral and phase-pulse evolution over the span of over two years by Kuiper et al (2012). Timing glitches associated with the January 2009 burst are the largest decrease spin-down ever observed in any magnetar to date. There are markedly different evolutionary behaviors for soft and hard pulsed x-ray components. The spectra in the immediate aftermath of the January 2009 burst are remarkably similar to persistent emission of quiescent magnetars. Interpretations and challenges presented by the burst evolution to current magnetar models are discussed.