Universiteit Leiden

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This Week’s Discoveries | 24 October 2017

24 oktober 2017
Oort Building
Niels Bohrweg 2
2333 CA Leiden
De Sitterzaal

First lecture

Nobel prize in Physics for the observation of Gravitational Waves

Jan Willem van Holten (LION)
Jan Willem is extraordinary professor of Theory of supergravity and cosmology at LION and staff member of the Theoretical Physics group at NIKHEF. His research involves the question how to construct quantum field-theoretical models incorporating new symmetries (such as supersymmetry) on the one hand, and gravity in a consistent manner on the other. He also investigates the physics of black holes, and gravitational waves.

Three American physicists (Rainer Weiss, Kip Thorne and Barry Barish) have won the Nobel prize in physics for the first observations of gravitational waves, ripples in the fabric of spacetime that were anticipated by Albert Einstein a century ago. All three scientists have played leading roles in the Laser Interferometer Gravitational-Wave Observatory, or Ligo, experiment, which in 2015 made the first historic observation of gravitational waves triggered by the violent merger of two black holes a billion light years away.

Second lecture

Galaxies 800 million years after the Big Bang seen with the Atacama Large Millimetre Array

Renske Smit (Cambridge)
Renske is an astronomer and postdoctoral fellow at the University of Cambridge in the UK, supported by a NWO Rubicon grant. Her research is focused on observations of galaxies in the very distant Universe, using telescopes such as the Hubble Space Telescope, the Spitzer Space Telescope and the Very Large Telescope of the European Southern Observatory in Chile. She is one of the participants of the workshopCharacterizing Galaxies with Spectroscopy with a view for JWST” that is being held in the Lorentz Center from 23 Oct 2017 through 27 Oct 2017.

The identification of galaxies in the first billion years after the Big Bang presents a challenge for even the largest optical telescopes. When the Atacama Large Millimetre Array (ALMA) started science operations in 2011 it presented a tantalising opportunity to identify and characterise these first sources of light in a new window of the electromagnetic spectrum. While scientists have struggled in the past few years to obtain strong sub-millimetre signals from galaxies in the earliest epoch of cosmic time, we have recently successfully identified new sources in this epoch using ALMA. Moreover, we study the gas kinematics of these distant sources for the first time and find that these galaxies likely already form rotating disks, such as seen in the star-forming galaxies much later in the Universe.