Joint IAS Princeton University Astrophysics Colloquium

Galaxy formation is a complex, hierarchical, highly non-linear process, which involves gravitational collapse of dark matter and baryons, supersonic, highly compressible and turbulent flows of gas, star formation, stellar feedback, as well as...

Failed supernovae, where core collapse leads to the formation of a black hole without an external supernova, have always been one of the possible outcomes when a massive star dies. The observed properties of the dying, progenitor stars, mismatches...

The source of about half of the heaviest elements in the Universe has been a mystery for a long time. Although the general picture of element formation is well understood, many questions about the nuclear physics processes and particularly the...

With current technology, young (<100 Myr) planets can be directly imaged - resolved from their parent star - in the near-infrared with adaptive optics. I will discuss results from such imaging, particularly the four-planet system orbiting HR8799. The outer two planets have been characterized spectroscopically using adaptive optics on the Keck telescope, showing non-equilibrium chemistry as well as evidence of composition enhanced in C/O from the original stellar nebula. The next step in direct imaging is Gemini Planet Imager and its counterparts on other telescopes. GPI is a a facility-class instrument operating on the Gemini South telescope, combining advanced adaptive optics with a coronagraph and near-infrared integral field spectrograph. Almost an order of magnitude more sensitive than current instruments, GPI had first light in November 2013. I will present an overview of the instrument and early science results including the orbit and spectrum of the planet Beta Pictoris b, polarization of the HR4796A circumstellar dust disk, and the status of the 600-star GPI Exoplanet Survey. Finally, I will discuss the potential of the WFIRST/AFTA space telescope for direct exoplanet imaging.

Anomalous X-ray Pulsars and Soft Gamma-Ray Repeaters (SGRs) are young neutron stars characterized by high X-ray quiescent luminosities, outbursts, and, in the case of SGRs, sporadic giant flares. They are believed to be magnetars, that is neutron...

Saturn’s satellite Enceladus displays a bewildering array of thermal activity. I will describe our attempts to understand these phenomena in terms of tidal heating associated with the 2:1 mean motion resonance between Enceladus and Dione. Then I...