Astrophysics Seminars

I will study generic single-field dark energy models, by a parametrization of the most general theory of their perturbations around a given background, including higher derivative terms. In appropriate limits this approach reproduces standard...

Although the observational evidence for cosmological inflation is growing, the physical mechanism behind it is still unknown. In part this is because inflation probably occurred at energy scales many orders of magnitude higher than that at man-made...

Magnetic activity in the Sun manifests itself as sunspot activity, flares, and reversals in the CaII H and K lines, and is believed to originate in the transition region between the convective and radiative zones. Lower- mass stars become fully...

Astronomers have exquisite observations of both galaxies (by directly imaging their stars) and of the intergalactic medium (in absorption spectra of background sources). While we know that the galactic baryons must have been accreted from the IGM...

The gas-phase oxygen abundances of star-forming galaxies are tightly correlated with the galaxies' stellar masses such that more massive galaxies are more oxygen-rich. Because oxygen is produced on relatively short timescales (~10 Myr), this so...