stars, pulsars, dark matter

I can't say I did much research today but I saw two beautiful talks, and going to talks does count as research.

At lunch time Dmitry Malyshev (NYU) gave a beautiful talk on millisecond-pulsar and dark-matter contributions to the observed haze at the Galactic Center from Fermi and WMAP. He showed specific pulsar-plus-DM models that explain the spectral properties of the haze beautifully, many of which are natural for both pulsars and the DM. In some, he had to make the electron–positron emission from pulsars very high, but it really is an unknown. He mentioned that 47 Tuc (globular cluster) is a key observable Fermi source for distinguishing these ideas. Malyshev was very cautious and made no strong claims, but my excitement about the possibility that dark matter annihilation is being observed grew during the presentation.

In the afternoon, Nathan Smith (Berkeley) gave an outstanding talk about extremely massive stars as observed in our own Galaxy and nearby galaxies, including their dramatic explosions and mass-loss episodes. These are incredibly rich in their kinematic and chemical properties and have implications for chemical abundance propagation, star formation, supernova prediction, and the evolution of the young universe. He made a comment at the end about extrapolating theories we don't understand into regimes where we have no data which made the astronomers laugh and the particle theorists ask And?.