Niels Bohr Lecture by Stephen Taylor, Vanderbilt University

Niels Bohr Lecture by Stephen Taylor, Vanderbilt University
Dr. Stephen Taylor is an Associate Professor of Physics & Astronomy and Chancellor’s Faculty Fellow at Vanderbilt University.

TITLE: Charting the Gravitational-wave Universe At Light-year Wavelengths

The Universe is thrumming with gravitational waves. June 2023 brought the first evidence for an all-sky background of nanohertz-frequency gravitational waves, discovered by collaborations including the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) and groups in Europe, Australia, India, and China. 

This was an endeavor decades in the making, requiring painstakingly precise timing observations of scores of millisecond pulsars across the Milky Way using flagship radio telescopes. While the results from separate groups are consistent with one another—and the leading interpretation of a population of supermassive black-hole binaries as the source—the observations provoke many new questions.

  • Do the results imply a population of binaries more massive than expected?
  • What are the observational milestones as the first resolvable binary signals come into focus?
  • Can we link these signals to their host galaxies through ranking protocols and by leveraging electromagnetic counterparts?
  • And will our understanding of the gravitational-wave background hit a cosmic-variance barrier?

In this talk, I will chart the path to discovery, reflect on what we have learned during our year+ since our announcement, and explore the exciting opportunities and synergies ahead—including the role of next-generation instruments radio instruments— as we move ever closer to the LISA era.

Bio:

Dr. Stephen Taylor is an Associate Professor of Physics & Astronomy and Chancellor’s Faculty Fellow at Vanderbilt University.

  • He studied Physics at the University of Oxford, followed by earning his PhD at the Institute of Astronomy of the University of Cambridge on topics in ground-based and pulsar-based gravitational-wave science.
  • He then held postdoctoral fellowships at NASA’s Jet Propulsion Laboratory and Caltech. Upon joining Vanderbilt in 2019, Stephen founded VIPER— the Vanderbilt Initiative in Probes of Extreme Relativity, and in 2021 he authored a textbook on Pulsar Timing Arrays that has become a standard reference for new and established researchers in the field.
  • Stephen chairs the NANOGrav Collaboration, leading the collaboration strategically, as well as co-leading the analysis campaign that produced the 2023 NANOGrav discovery of a stochastic background of low-frequency gravitational waves, thereby opening an entirely new band of gravitational-wave astronomy.
  • His group develops advanced statistical and modeling approaches to probe anisotropy, polarization, and non-stationarity in the background and to hunt for resolvable supermassive black-hole binaries, with close ties to NANOGrav, IPTA, LISA, LSST, and DSA-2000 efforts.
  • He is also a member of the LISA Science Team, tasked with steering the development of the LISA mission to ensure it meets its science objectives.
  • He is funded by the US National Science Foundation and NASA, and a recipient of the NSF’s prestigious CAREER Award.

Stephen was named the 2024 Kavli Prize Plenary Lecturer by the American Astronomical Society, the 2024 Eddington Lecturer by the University of Cambridge and the Royal Astronomical Society, and was selected as a Young Leader for the 2024 Science & Technology in Society Forum in Kyoto.