Book a RAS A&G Highlights January 2024 Online or In Person Ticket
16:00 Prof Mike Edmunds – Welcome
16:05 Interstellar Mapping and Acceleration Probe (IMAP) mission: Exploring our solar neighbourhood
Dr. Matina Gkioulidou (APL, JHU, USA)
The heliosphere – our home in the galaxy – is the region of space surrounding our solar system and dominated by the Sun’s presence. It is formed by the million mile-per-hour solar wind, which blows outward from the Sun all directions in space, inflating a bubble in the local interstellar medium.
The heliosphere provides a shield against the harsh radiation present in the galaxy, thereby creating and maintaining a habitable solar system. Understanding the physics of this boundary and its dynamic changes over time can help us comprehend how our solar system can support life as we know it.
NASA’s Interstellar Mapping and Acceleration Probe (IMAP) mission (https://imap.princeton.edu/), launching in 2025, with a suite of 10 instruments and an international team of 24 partner institutions, creates a comprehensive map of the Sun’s environment, including high-energy particles and magnetic fields in interplanetary and interstellar space.
This groundbreaking mission, simultaneously investigates two of the most important problems in space physics today, the acceleration of particles expelled from the Sun to high energies, and how the interaction of these high energy particles with the local interstellar medium shapes our heliosphere.
Dr. Matina Gkioulidou is a space physicist at the Johns Hopkins Applied Physics Laboratory, with expertise that spans different space plasma regimes, from particle acceleration processes in the Earth's magnetosphere during geomagnetic storms, to our heliosphere’s interactions with the local interstellar medium. She is the Project Scientist of NASA’s Interstellar Mapping and Acceleration Probe (IMAP) mission. She is also the Lead of the IMAP-Ultra Energetic Neutral Atom (ENA) camera. Dr. Gkioulidou has been a member of NASA's Living With a Star Program Analysis Group, NSF's Geospace Environment Modeling Science Steering Committee, and NASA’s Heliophysics Advisory Committee.
16:35 “Simulation Based Inference of the Kilo-Degree Survey”
Kiyam Lin (UCL)
Cosmic shear has shown itself to be a good tracer for the large-scale structure of the Universe. However, the standard approach to inference from cosmic large-scale structure data employs summary statistics that are compared to analytic models in a Gaussian likelihood with pre-computed covariance.
To overcome the idealising assumptions about the form of the likelihood and the complexity of the data inherent to the standard approach, we investigate simulation-based inference (SBI), which learns the likelihood as a probability density parameterised by a neural network.
We apply this technique to new simulations constructed for the most recent Kilo-Degree Survey (KiDS) weak gravitational lensing analysis and demonstrate the power of SBI by inferring a 7-dimensional KiDS posterior distribution. Furthermore, we make use of the machine learning architecture to probe different levels of Gaussianity in the newly learned likelihood and test the robustness of the inference done.
Kiyam is a final year PhD student at UCL, London, where he works on the task of statistical inference powered by machine learning applied to the large scale structure of the Universe. Kiyam has so far greatly enjoyed his PhD as it has really brought to light the power of machine learning and computation in general in tackling problems that are simply too hard with pen and paper. Prior to his PhD, Kiyam has spent several years working in industry after graduating from Imperial College London with a MSci in Physics. During those years, Kiyam dabbled extensively in both data science and animation work and is bemused by the fact that the nature of work between industry and academia is often very different even if in both instances one is working on analysing data.
16:55 “Asteroseismology unlocks the hidden physics of stellar interiors”
Dr Dominic Bowman (Newcastle University) – George Darwin Lecture
Massive stars are important factories in the Universe since they provide kinematic, chemical, and radiative feedback to their surroundings through their winds and explosive deaths as supernovae. However, our models for how massive stars evolve currently contain large uncertainties for physical mechanisms at work in their deep interiors. The uncertainties associated with unknown interior rotation profiles, chemical mixing processes, and angular momentum transport mechanisms propagate throughout evolution making it difficult to accurately determine their masses and ages, thus complicating our predictions of supernovae yields.
However, asteroseismology - the study of stellar pulsations - allows us to break model parameter degeneracies, uniquely probe the physics of stellar interiors, and constrain uncalibrated prescriptions in our models. In my 2023 George Darwin Lecture, I provide an introduction of asteroseismology for the non-expert, and discuss its application to massive stars using high-precision photometric time-series data from space telescopes and state-of-the-art stellar evolution models. I present recent novel constraints on the interior rotation, mixing properties, and magnetic fields from forward asteroseismic modelling of massive stars, and conclude with a future outlook on this ever-expanding field within stellar astrophysics.
Dominic completed his PhD in astronomy at the University of Central Lancashire under the supervision of Prof. Donald Kurtz in 2016, and was a recipient of the Springer Thesis Prize for "Outstanding PhD Research". In 2017 he began a postdoctoral research position at KU Leuven in Belgium, and in 2020 he was awarded a competitive FWO research fellowship in massive star asteroseismology. In September 2023, Dominic began a Readership faculty position at Newcastle University, and currently holds a prestigious Royal Society University Research Fellowship and an ERC/UKRI Frontier Research Grant. Dominic has been invited dozens of times as a speaker at international conferences and has won prestigious prizes for research excellence, including the KU Leuven Research Council Award in 2020, the Henri Vanderlinden Prize of the Flemish Academy in 2022, and the George Darwin Lectureship of the Royal Astronomical Society in 2023. In addition to being an outstanding researcher, Dominic is passionate about developing teaching at the BSc, MSc and PhD levels, and engages regularly in advocacy and mentoring activities for all ages and backgrounds.
18:00 Drinks Reception – RAS Council Room
Book a RAS A&G Highlights January 2024 Online or In Person Ticket