Book a RAS A&G Highlights March 2024 Online or In Person Ticket
Extreme Space Weather Events
Dr Ravindra Desai, Winton G
Space Weather is influenced by phenomena operating across a multitude of scales, from the large-scale expulsion and evolution of coronal mass ejections from the solar corona, to particle-scale interactions within the Earth’s radiation belts. My interests within plasma simulations focus on both large-scale fluid physics and kinetic processes and the interplay between them. In this seminar I will start with Sun-to-Earth studies of coronal mass ejections and review some of the largest geomagnetic storms on record and examine under what conditions “Carrington-scale” events are possible. I will then discuss how these impulsive injections of energy flow through the coupled Sun-Earth system and present an imminent danger to our increasingly technology-reliant society. In particular, I will focus on how non-thermal particle distributions can be rapidly created within the magnetosphere and the transport processes responsible. Following this I will discuss the outstanding questions in space weather forecasting and missing links in the chain towards building a digital twin of the geospace environment.
Ravindra Desai is an Assistant Professor at the University of Warwick. His research into astrophysical plasmas incorporates both particle-scale kinetic physics and system-scale phenomena, to pursue blue skies research into how plasma dynamics govern astrophysical systems – across the solar system and beyond. He is also interested in how astrophysical plasma processes can intersect with, and pose dangers to, our increasingly technology-dependent society through phenomena collectively known as Space Weather.
Massive black holes during the first billion years with the James Webb Space Telescope
Hannah Übler
The James Webb Space Telescope (JWST) has opened a new window into the first billion years of cosmic time through unprecedented, sensitive imaging and spectroscopy. JWST provides access to rest-frame optical emission at z>4, impossible to get with ground-based facilities. Since its launch, one of the major areas of research with JWST has been the quest for the first black holes. Black holes with masses in excess of millions to billions of solar masses are found in all massive galaxies in the local Universe, yet their formation and growth mechanisms remain largely unknown. I will present results from the JWST/NIRSpec GTO team on massive black holes during the first billion years, and their impact on their young host galaxies in the form of powerful outflows and ionizing radiation. I will also discuss observational constraints on early black hole growth, and the prospect for future advances in this field.
Hannah Übler is currently a Newton-Kavli Fellow at the Kavli Institute for Cosmology and the Cavendish Laboratory at the University of Cambridge, UK. Who obtained her Dr.rer.nat. (PhD in Astronomy) in 2019 from the University of Munich, Germany, working at the Max Planck Institute for extraterrestrial Physics in Garching on galaxy kinematics during the peak epoch of cosmic star formation. Hannah also hold a Magister Artium in Philosophy from the University of Munich. Her research focusses on the formation and evolution of galaxies and massive black holes, most recently using the NIRSpec instrument on board JWST, as part of the NIRSpec GTO team and as co-lead of the NIRSpec-IFS GTO survey GA-NIFS.
The Dawn of Galaxy-scale Gravitational Wave Astronomy
Dr Stephen Taylor, Eddington lecture
For more than 15 years, NANOGrav and other pulsar-timing array collaborations have been carefully monitoring networks of pulsars across the Milky Way. The goal was to find a tell-tale correlation signature amid the data from all those pulsars that would signal the presence of an all-sky background of nanohertz-frequency gravitational waves, washing through the Galaxy. At the end of June 2023, the global pulsar-timing array community finally announced its evidence for this gravitational-wave background, along with a series of studies that interpreted this signal as either originating from a population of supermassive black-hole binary systems, or as relics from cosmological processes in the very early Universe. I will describe the journey up to this point (including the integral role that the IoA played), what led to the ultimate breakthrough, how this affects our knowledge of supermassive black holes and the early Universe, and what lies next for gravitational-wave astronomy at light-year wavelengths.
Dr Stephen Taylor is a Northern Irish astrophysicist and Assistant Professor at Vanderbilt University in Nashville, Tennessee. He has an undergraduate degree in Physics from the University of Oxford in 2010, followed by a PhD from the University of Cambridge in 2014 where he worked with Dr. Jonathan Gair at the Institute of Astronomy. After postdoctoral fellowships at NASA’s Jet Propulsion Laboratory and Caltech, he joined Vanderbilt University as faculty in 2019. Stephen Taylor is the recipient of the US National Science Foundation’s prestigious CAREER award, and was recently named as the 2024 Kavli Plenary Lecturer by the American Astronomical Society. He co-led the North American Nanohertz Observatory for Gravitational waves' analysis campaign that resulted in the first evidence for an all-sky background of gravitational waves at light-year wavelengths, and currently serves as the Chair and spokesperson of the NANOGrav collaboration.
Book a RAS A&G Highlights March 2024 Online or In Person Ticket