Thunch schedule for Spring 2018 (12:15 - 1:15)


  • Feb 8
    • Yuan-Sen Ting
    • Postdoc, Princeton University
    • Title: The new era of Galactic Archaeology
    • Abstract: Understanding physical processes responsible for the formation and evolution of galaxies like the Milky Way is a fundamental problem. However, a key challenge is that the properties and orbits of the stars can only be observed at present: to understand what happened in the Milky Way at earlier epochs, one must explore “archaeological” techniques. I will discuss the opportunities associated with Galactic archaeology with the on-going large scale multiplexing spectroscopic surveys, including a first quantitative constraint on the radial migration of stars and on the disrupted cluster mass function in the Milky Way. I will also describe a new set of tools for efficient measuring > 20 elemental abundances from low-resolution R=2000 spectra, for discovering spectroscopically unresolved binaries, and for inferring asteroseismic parameters directly from single-epoch spectra.

  • Feb 15
    • Steve Choi
    • Grad student, Princeton University
    • Title: Precision Cosmology with Advanced ACTPol
    • Abstract: The Advanced ACTPol upgrade on the Atacama Cosmology Telescope aims to improve the measurement of the cosmic microwave background anisotropies and polarization, using four new dichroic detector arrays fabricated on 150-mm silicon wafers. In 2016, the Atacama Cosmology Telescope began mapping approximately half the sky with increased sensitivity using these new detector arrays. I will discuss the performance of the Advanced ACTPol upgrade and the improved constraints on cosmology.

  • Feb 22
    • Cole Holcomb
    • Grad student, Princeton University
    • Title: Gyroresonant Streaming Instability and Implications for Nonlinear Cosmic Ray Transport
    • Abstract: Cosmic rays (CRs) are known to be an often energetically significant component of interstellar and intracluster media. The interplay between CRs and the ambient magnetic field can produce observational signatures (e.g. CR isotropy, radio halos of galaxy clusters, etc..) and even impact galactic evolution on large scales (e.g. galactic winds). Modeling these effects has relied on ill-understood and generally unvalidated linear/quasilinear analytical models for the gyroresonant interaction between CRs and magnetic fields. We perform microphysical simulations of the gyroresonant CR streaming instability and discuss implications for modeling the associated large scale physics.


  • Mar 1
    • Edo Berger
    • Professor, Harvard
    • host: Jia Liu
    • Title: Rattle and Shine: Joint Detection of Gravitational Waves and Light from the Binary Neutron Star Merger GW170817
    • Abstract: The much-anticipated joint detection of gravitational waves and electromagnetic radiation was achieved for the first time on August 17, 2017, for the binary neutron star merger GW170817. This event was detected by Advanced LIGO/Virgo, gamma-ray satellites, and dozens of telescopes on the ground and in space spanning from radio to X-rays. In this talk I will describe the exciting discovery of the optical counterpart, which in turn led to several detailed studies across the electromagnetic spectrum. The results of the observations carried out by our team include the first detailed study of a "kilonova", an optical/infrared counterpart powered by the radioactive decay of r-process nuclei synthesized in the merger, as well as the detection of an off-axis jet powering radio and X-ray emission. These results provide the first direct evidence that neutron star mergers are the dominant site for the r-process and are the progenitors of short GRBs. I will also describe how studies of the host galaxy shed light on the merger timescale, and describe initial constraints on the Hubble Constant from the combined GW and EM detection.

  • Mar 8
    • John Hoffman
    • Grad student, Princeton University

  • Mar 15
    • Joshua Wallace
    • Grad student, Princeton University
    • host:

  • Mar 29
    • [your name here]
    • [your affiliation here]
    • host: [your host here]

  • Apr 5
    • [your name here]
    • [your affiliation here]
    • host: [your host here]

  • Apr 12
    • Kris Pardo
    • Grad student, Princeton University
    • host: [your host here]

  • Apr 19
    • [your name here]
    • [your affiliation here]
    • host: [your host here]

  • Apr 26
    • Spitzer lecturer?
  • May 3
    • Spitzer lecturer?

  • May 10
    • [your name here]
    • [your affiliation here]
    • host: [your host here]

  • May 17
    • Fei Dai
    • Grad student, MIT/Princeton
    • host: [your host here]

  • May 24
    • Frans Pretorius
    • Professor, Princeton University

  • May 31
    • John Stocke
    • host: Michael Strauss