3:00–5:00 pm ERC 401
Speakers: Dan Baxter, Cosmin Deaconu, Reed Essick, and Alex Alarcon Gonzalez
Organizers: Dan Baxter, Anne Gambrel, and Yiming Zhong
- 2:30 - 3:00PM Coffee/cookies
- 3:00 - 3:30 Reed Essick
- "Gravitational Laboratories for Nuclear Physics"
Gravitational waves provide a completely new way to study the universe. From the initial direct detection of coalescing black holes in 2015, to the ground-breaking multimessenger observations of coalescing neutron stars in 2017, and continuing with the now routine detection of merging stellar remnants, gravitational wave astronomy has quickly matured into a key aspect of modern physics. I will briefly review my role in these detections before discussing novel tests of fundamental physics they enabled. In particular, I will focus on our current understanding of matter effects during the inspiral of compact binaries and matter at supranuclear densities, including possible phase transitions, through tests of neutron star structure. Detailed knowledge of dynamical interactions between coalescing stars, observations of extreme relativistic astrophysical systems, terrestrial experiments, and nuclear theory provide complementary views of fundamental physics. I will show how combining aspects from all these will improve our understanding of dense matter and the most extreme environments in the universe. - 3:30 - 4:00 Cosmin Deaconu
- "In-Ice Radio Neutrino Detectors, Past and Future"
- 4:00 - 4:30 Alex Alarcon Gonzalez
- "Redshift inference from the combination of galaxy colors and clustering in a hierarchical Bayesian model"
Photometric galaxy surveys constitute a powerful cosmological probe but rely on the accurate characterization of their redshift distributions using only broadband imaging, and can be very sensitive to incomplete or biased priors used for redshift calibration. Several techniques for estimating the redshift distributions of imaging surveys have been developed in the last decades, which can be broadly separated in three categories: 1) direct calibration through spectroscopic redshifts, 2) mapping the relation between photometry and redshift with a mix of theoretical models of galaxy spectra and empirical knowledge from direct spectroscopy, and 3) comparing the sky positions of galaxies to the positions of a tracer population with secure redshifts. Here we present a hierarchical Bayesian model which combines these three main sources of information so it can be applied to real data. We test the method in N-body simulations and find the incorporation of clustering information on top of photometry to tighten the redshift posteriors and overcome biases in the prior that mimic those happening in spectroscopic samples. This robustness to flaws in the redshift prior or training samples would constitute a milestone for the control of redshift systematic uncertainties in future weak lensing analyses. - 4:30 - 5:00 Dan Baxter
- "New Channels in the Search for Dark Matter"
- 5:00 - 6:00 Wine and Cheese Reception
Event Type
Mar
6