Thu 05 Jun 16:00: The Formation and Co-Evolution of Galaxies and Supermassive Black Holes
Cosmological hydrodynamical simulations are becoming increasingly realistic by incorporating a wider range of physical processes, higher spatial resolution, and larger statistical samples. Despite ongoing trade-offs between resolution and volume, recent advances now allow for simulations that resolve the multiphase interstellar medium and capture the clumpy nature of star formation in galaxies. In this context, I will present how such simulations shed light on the coupled evolution of galaxies and their central supermassive black holes. At high redshift, galaxies tend to be gas-rich, turbulent, and star-bursting, often exhibiting irregular, compact, and disturbed morphologies. As internal turbulence subsides, many systems transition into stable, rotating disc galaxies, typically once they reach stellar masses around 1e10 Msun. Simultaneously, black hole growth is tightly linked to the dynamical state of the host galaxy. In low-mass, turbulent systems, stellar feedback can suppress nuclear gas inflows, delaying black hole growth. Only when galaxies become sufficiently massive and dynamically settled can gas efficiently reach galactic centers to fuel sustained accretion. These processes also have important implications for the spin evolution of black holes or how fast they coalesce, which can reflect the varying modes of accretion and feedback across cosmic time.
- Speaker: Yohan Dubois (Institut d’Astrophysique de Paris)
- Thursday 05 June 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Thu 05 Jun 16:00: The Formation and Co-Evolution of Galaxies and Supermassive Black Holes
Cosmological hydrodynamical simulations are becoming increasingly realistic by incorporating a wider range of physical processes, higher spatial resolution, and larger statistical samples. Despite ongoing trade-offs between resolution and volume, recent advances now allow for simulations that resolve the multiphase interstellar medium and capture the clumpy nature of star formation in galaxies. In this context, I will present how such simulations shed light on the coupled evolution of galaxies and their central supermassive black holes. At high redshift, galaxies tend to be gas-rich, turbulent, and star-bursting, often exhibiting irregular, compact, and disturbed morphologies. As internal turbulence subsides, many systems transition into stable, rotating disc galaxies, typically once they reach stellar masses around 1e10 Msun. Simultaneously, black hole growth is tightly linked to the dynamical state of the host galaxy. In low-mass, turbulent systems, stellar feedback can suppress nuclear gas inflows, delaying black hole growth. Only when galaxies become sufficiently massive and dynamically settled can gas efficiently reach galactic centers to fuel sustained accretion. These processes also have important implications for the spin evolution of black holes or how fast they coalesce, which can reflect the varying modes of accretion and feedback across cosmic time.
- Speaker: Yohan Dubois (Institut d’Astrophysique de Paris)
- Thursday 05 June 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Fri 06 Jun 11:30: Exploring the End of Reionization
Abstract not available
- Speaker: George Becker (UC Riverside)
- Friday 06 June 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Wed 11 Jun 13:15: Neurodiversity and Communication Styles
Dr Maria Dias, Neurodiversity Adviser at the Accessibility and Disability Resource Centre (ADRC) and St Catharine’s College, will explore how people with different neurotypes communicate in unique ways, and why understanding these differences is important for creating more inclusive and supportive environments. Whether you’re neurodivergent yourself, work with neurodivergent people, or just want to learn more, this talk is for you. There will be time for questions and open discussion at the end.
- Speaker: Maria Dias, Neurodiversity Adviser at the Accessibility and Disability Resource Centre (ADRC) and St Catharine’s College
- Wednesday 11 June 2025, 13:15-14:05
- Venue: The Hoyle Lecture Theatre + Zoom .
- Series: Institute of Astronomy Seminars; organiser: Cristiano Longarini.
Wed 11 Jun 13:15: Neurodiversity and Communication Styles
Dr Maria Dias, Neurodiversity Adviser at the Accessibility and Disability Resource Centre (ADRC) and St Catharine’s College, will explore how people with different neurotypes communicate in unique ways, and why understanding these differences is important for creating more inclusive and supportive environments. Whether you’re neurodivergent yourself, work with neurodivergent people, or just want to learn more, this talk is for you. There will be time for questions and open discussion at the end.
- Speaker: Maria Dias, Neurodiversity Adviser at the Accessibility and Disability Resource Centre (ADRC) and St Catharine’s College
- Wednesday 11 June 2025, 13:15-14:05
- Venue: The Hoyle Lecture Theatre + Zoom .
- Series: Institute of Astronomy Seminars; organiser: Cristiano Longarini.
Mon 02 Jun 16:00: Imaging and Design with Differentiable Physics Models
The technology that underpins machine learning – differentiable programming – is poised to revolutionise astronomy, making it possible for the first time to fit very high dimensional models: hierarchical models describing many objects; the sensitivity of millions of pixels in a detector; models of images or spectra with very many free parameters; or neural networks that represent physics we cannot easily solve in closed form. It also enables fundamental information-theoretic quantities like the Fisher information to be calculated, allowing for determination and optimization of the information content of an experiment. I will discuss how we apply this to the James Webb interferometer experiment, to provide a data-driven self-calibration of the telescope’s highest resolution mode and its difficult systematics; to design the Toliman Space Telescope to do high-precision, distortion-tolerant astrometry; and give an overview of related work on interferometry, transits and AGN reverberation mapping in our group.
- Speaker: Benjamin Pope (Macquarie University)
- Monday 02 June 2025, 16:00-17:00
- Venue: Martin Ryle Seminar Room, KICC.
- Series: Astro Data Science Discussion Group; organiser: km723.
Gas meets Kozai: the influence of a gas-rich accretion disc on hierarchical triples undergoing von Zeipel-Lidov-Kozai oscillations
Gas meets Kozai: the influence of a gas-rich accretion disc on hierarchical triples undergoing von Zeipel-Lidov-Kozai oscillations
Mon 09 Jun 13:00: Pulsar Timing Arrays and Astrometry: Going Beyond the Hellings-Downs correlation
The detection of gravitational waves (GWs) by pulsar timing arrays (PTAs) opens new avenues for probing the physics of GW sources at nanohertz frequencies. In the same frequency band, astrometric observations may also enable future GW detections. It is therefore important to investigate the potential for cross-correlating these two complementary approaches. Accordingly, I will discuss three topics related to the characterization of the stochastic gravitational-wave background using pulsar timing arrays and astrometry. The potential detection of its kinematic dipole. The prospects for measuring its circular polarization. A new method for identifying the possible presence of scalar polarization in the GW background.
- Speaker: Gianmassimo Tasinato (Swansea University)
- Monday 09 June 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Thomas Colas.
Mon 02 Jun 13:00: Cracks in the Standard Cosmological Model: Anomalies, Tensions, and Hints of New Physics
The ΛCDM model has long served as the standard paradigm in cosmology, offering a remarkably successful description of the Universe’s evolution. Yet, as observational precision continues to improve, persistent tensions have emerged across a range of probes, including the well-known Hubble constant discrepancy. While individual datasets may each align with ΛCDM, their collective interpretation reveals significant discordances that challenge the model’s internal consistency. In this talk, I will review the most prominent tensions in modern cosmology and assess their implications. I will present recent results pointing to hints of dynamical dark energy and interactions within the dark sector. I will also reflect on the growing influence of methodological choices, such as dataset selection and model assumptions, in shaping our cosmological conclusions.
- Speaker: Eleonora Di Valentino (University of Sheffield)
- Monday 02 June 2025, 13:00-14:00
- Venue: SPECIAL LOCATION - CMS, MR4, Pav A basement.
- Series: Cosmology Lunch; organiser: Thomas Colas.
Hubble Spies Paired Pinwheel on Its Own
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Hubble Spies Paired Pinwheel on Its Own This NASA Hubble Space Telescope image features the beautiful barred spiral galaxy NGC 3507 ESA/Hubble & NASA, D. ThilkerA single member of a galaxy pair takes centerstage in this NASA/ESA Hubble Space Telescope image. This beautiful spiral galaxy is NGC 3507, which is situated about 46 million light-years away in the constellation Leo (the Lion). NGC 3507’s classification is a barred spiral because the galaxy’s sweeping spiral arms emerge from the ends of a central bar of stars rather than the central core of the galaxy.
Though pictured solo here, NGC 3507 actually travels the universe with a galactic partner named NGC 3501 that is located outside the frame. While NGC 3507 is a quintessential galactic pinwheel, its partner resembles a streak of quicksilver across the sky. Despite looking completely different, both are spiral galaxies, simply seen from different angles.
For galaxies that are just a few tens of millions of light-years away, like NGC 3507 and NGC 3501, features like spiral arms, dusty gas clouds, and brilliant star clusters are on full display. More distant galaxies appear less detailed. See if you can spot any faraway galaxies in this image: they tend to be orange or yellow and can be anywhere from circular and starlike to narrow and elongated, with hints of spiral arms. Astronomers use instruments called spectrometers to split the light from these distant galaxies to study the nature of these objects in the early universe.
In addition to these far-flung companions, a much nearer object joins NGC 3507. The object is marked by four spikes of light: a star within the Milky Way, a mere 436 light-years away from Earth.
Text Credit: ESA/Hubble
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubbleMedia Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
- Hubble Space Telescope
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Science Behind the Discoveries
Tue 10 Jun 16:00: Title to be confirmed
Abstract not available
- Speaker: Daniel Muthukrishna (MIT)
- Tuesday 10 June 2025, 16:00-17:00
- Venue: Martin Ryle Seminar Room, KICC.
- Series: Astro Data Science Discussion Group; organiser: km723.
Wed 04 Jun 13:40: GPU Accelerated Sampling and Model Comparison
This talk introduces a natively vectorized implementation of the Nested Sampling algorithm, enabling deployment of the entire inference process onto GPUs for massive acceleration. I will start by reviewing the benefits, and necessity, of the paradigm shift towards vectorized compute in the physical sciences. After a brief review of the how (and why) of Bayesian inference in Astronomy and Cosmology, I will then explore the nuances and challenges of taking some of the widely used inference algorithms within this community, in particular nested sampling, to the GPU accelerated frontier. Lastly I’ll present some practical benefit that this speedup can bring and comment on how this technical development can help push the boundaries of what we can achieve in the physical sciences.
- Speaker: David Yallup / IoA
- Wednesday 04 June 2025, 13:40-14:05
- Venue: The Hoyle Lecture Theatre + Zoom .
- Series: Institute of Astronomy Seminars; organiser: .
Wed 04 Jun 13:40: GPU Accelerated Sampling and Model Comparison
This talk introduces a natively vectorized implementation of the Nested Sampling algorithm, enabling deployment of the entire inference process onto GPUs for massive acceleration. I will start by reviewing the benefits, and necessity, of the paradigm shift towards vectorized compute in the physical sciences. After a brief review of the how (and why) of Bayesian inference in Astronomy and Cosmology, I will then explore the nuances and challenges of taking some of the widely used inference algorithms within this community, in particular nested sampling, to the GPU accelerated frontier. Lastly I’ll present some practical benefit that this speedup can bring and comment on how this technical development can help push the boundaries of what we can achieve in the physical sciences.
- Speaker: David Yallup / IoA
- Wednesday 04 June 2025, 13:40-14:05
- Venue: The Hoyle Lecture Theatre + Zoom .
- Series: Institute of Astronomy Seminars; organiser: .
Tue 21 Oct 11:15: Title TBC
Abstract TBC
- Speaker: Dr. Weiyang Wang (University of Chinese Academy of Sciences)
- Tuesday 21 October 2025, 11:15-12:00
- Venue: TBC.
- Series: Hills Coffee Talks; organiser: Charles Walker.