Fri 31 May 11:30: Title to be confirmed
Abstract not available
- Speaker: Sinan Deger (KICC)
- Friday 31 May 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Wed 22 May 11:30: Hierarchical star cluster assembly boosts intermediate-mass black hole formation
Observations and high-resolution hydrodynamical simulations indicate that massive star clusters assemble hierarchically from sub-clusters with a universal power-law cluster mass function. We study the consequences of such assembly for the formation of intermediate-mass black holes (IMBHs) and massive black hole (MBH) seeds at low metallicities (1% of the solar value) with our updated direct N-body code BIFROST in simulations up to N = 2.35 million stars. The GPU -accelerated code BIFROST is based on the hierarchical fourth-order forward integrator. Few-body systems are treated using secular and regularized techniques including post-Newtonian equations of motion up to order PN3 .5 and gravitational-wave recoil kicks for merging BHs. Stellar evolution is provided by the fast population synthesis code SEVN . IMBHs with masses up to 2200 solar masses form rapidly mainly via the collapse of very massive stars (VMSs) assembled through repeated collisions of massive stars followed by growth through tidal disruption events (TDEs) and BH mergers. Later the IMB Hs form subsystems resulting in gravitational-wave BH-BH, IMBH -BH and IMBH -IMBH mergers with a 1000 solar mass gravitational-wave detection being the observable prediction. Our simulations indicate that the hierarchical formation of massive star clusters in metal poor environments naturally results in formation of potential seeds for supermassive black holes.
- Speaker: Antti Rantala (MPA)
- Wednesday 22 May 2024, 11:30-12:30
- Venue: Martin Ryle Meeting Room, KICC + Online.
- Series: Kavli Institute for Cosmology Seminars; organiser: Alison Wilson.
Thu 16 May 16:00: Inside Astronomically Realistic Black Holes
I will use a real-time general relativistic Black Hole Flight Similator to show what really happens inside astronomically realistic black holes. The inner horizon of a rotating black hole is the most violent place in the Universe, easily reaching and surpassing energy densities attained in the Big Bang. What does Nature do at this extraordinary place?
- Speaker: Prof. Andrew Hamilton (University of Colorado Boulder)
- Thursday 16 May 2024, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: eb694.
Tue 07 May 11:30: KICC Special Seminar (Title TBC)
Abstract not available
- Speaker: Tsevi Mazeh (Tel Aviv)
- Tuesday 07 May 2024, 11:30-12:30
- Venue: Hoyle Lecture Theatre + ONLINE - Details will be sent by email.
- Series: Kavli Institute for Cosmology Seminars; organiser: Alison Wilson.
Fri 07 Jun 11:30: Title to be confirmed
Abstract not available
- Speaker: Arjen van der Wel (Ghent University)
- Friday 07 June 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 21 Jun 11:30: Modelling supermassive black holes: accretion, spin evolution, jets and winds
Abstract not available
- Speaker: Martin Bourne (IoA)
- Friday 21 June 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Tue 07 May 11:30: TBD
Abstract not available
- Speaker: Tsevi Mazeh (Tel Aviv)
- Tuesday 07 May 2024, 11:30-12:30
- Venue: Hoyle Lecture Theatre + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 03 May 11:30: TBD (have to move to May 7?)
Abstract not available
- Speaker: Tsevi Mazeh (Tel Aviv)
- Friday 03 May 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 12 Apr 11:30: Chemo-dynamical evolution of disks over cosmic time
Abstract not available
- Speaker: Emily Wisnioski (ANU)
- Friday 12 April 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 14 Jun 11:30: Title to be confirmed
Abstract not available
- Speaker: Georges Meynet (Geneva)
- Friday 14 June 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Tue 23 Apr 13:00: Title to be confirmed
Abstract not available
- Speaker: Nathan Magnan (DAMTP)
- Tuesday 23 April 2024, 13:00-14:00
- Venue: Hoyle Committee Room + ONLINE - Details to be sent by email.
- Series: Exoplanet Seminars; organiser: Dr Dolev Bashi.
Tue 11 Jun 13:00: Title to be confirmed
Abstract not available
- Speaker: Anna Miotello (ESO)
- Tuesday 11 June 2024, 13:00-14:00
- Venue: Ryle seminar room + ONLINE - Details to be sent by email.
- Series: Exoplanet Seminars; organiser: Dr Dolev Bashi.
Tue 04 Jun 13:00: Title to be confirmed
Abstract not available
- Speaker: Paola Pinilla (MSSL)
- Tuesday 04 June 2024, 13:00-14:00
- Venue: Ryle seminar room + ONLINE - Details to be sent by email.
- Series: Exoplanet Seminars; organiser: Dr Dolev Bashi.
Tue 30 Apr 13:00: Title to be confirmed
Abstract not available
- Speaker: Florian Lienhard (Zurich)
- Tuesday 30 April 2024, 13:00-14:00
- Venue: Ryle seminar room + ONLINE - Details to be sent by email.
- Series: Exoplanet Seminars; organiser: Dr Dolev Bashi.
Tue 14 May 13:00: Title to be confirmed
Abstract not available
- Speaker: Emily Sandford (Cavendish)
- Tuesday 14 May 2024, 13:00-14:00
- Venue: Ryle seminar room + ONLINE - Details to be sent by email.
- Series: Exoplanet Seminars; organiser: Dr Dolev Bashi.
Fri 03 May 11:30: Title to be confirmed
Abstract not available
- Speaker: Tsevi Mazeh (Tel Aviv)
- Friday 03 May 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Thu 02 May 16:00: Experimental Studies of Black Holes: Status & Prospects
More than a century ago, Albert Einstein presented his general theory of gravitation. One of the predictions of this theory is that not only particles and objects with mass, but also the quanta of light, photons, are tied to the curvature of space-time, and thus to gravity. There must be a critical mass density, above which photons cannot escape. These are black holes. It took fifty years before possible candidate objects were identified by observational astronomy. Another fifty years have passed, until we finally can present detailed and credible experimental evidence that black holes of 10 to 1010 times the mass of the Sun exist in the Universe. Three very different experimental techniques have enabled these critical experimental breakthroughs. It has become possible to investigate the space-time structure in the vicinity of the event horizons of black holes. I will summarize these interferometric techniques, and discuss the spectacular recent improvements achieved with all three techniques. In conclusion, I will sketch where the path of exploration and inquiry may lead to in the next decades.
- Speaker: Reinhard Genzel (Max Planck Institute for Extraterrestrial Physics)
- Thursday 02 May 2024, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy (and online - details to be sent by e-mail).
- Series: The Kavli Lectures; organiser: Alison Wilson.
Fri 07 Jun 11:30: Modelling supermassive black holes: accretion, spin evolution, jets and winds
Abstract not available
- Speaker: Martin Bourne (IoA)
- Friday 07 June 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Wed 27 Mar 10:00: pop-cosmos: Comprehensive Forward Modelling of Photometric Galaxy Survey Data
Projects such as the imminent Vera C. Rubin Observatory are critical tools for understanding cosmological questions like the nature of dark energy. By observing huge numbers of galaxies, they enable us to map the large scale structure of the Universe. To do this, however, we need reliable ways of estimating galaxy redshifts from only photometry. I will present an overview of our pop-cosmos forward modelling framework for photometric galaxy survey data, a novel approach which connects photometric redshift inference to a physical picture of galaxy evolution. Within pop-cosmos, we model galaxies as draws from a population prior distribution over redshift, mass, dust properties, metallicity, and star formation history. These properties are mapped to photometry using an emulator for stellar population synthesis (speculator/photulator), followed by the application of a learned model for a survey’s noise properties. Application of selection cuts enables the generation of mock galaxy catalogues. This naturally enables us to use simulation-based inference to solve the inverse problem of calibrating the population-level prior on physical parameters from a deep photometric galaxy survey. The resulting model can then be used to derive accurate redshift distributions for upcoming photometric surveys, for instance for facilitating weak lensing and clustering science. We use a diffusion model as a flexible population-level prior, and optimise its parameters by minimising the Wasserstein distance between forward-simulated photometry and the real survey data. I will show applications of this framework to COSMOS data, and will demonstrate how we are able to extract the redshift distribution, and make inference about galaxy physics, from our learned population prior.
- Speaker: Stephen Thorp - Oskar Klein Centre, Stockholm University
- Wednesday 27 March 2024, 10:00-11:00
- Venue: Martin Ryle Seminar Room, KICC.
- Series: Astro Data Science Discussion Group; organiser: Sinan Deger.
Fri 03 May 11:30: Modelling supermassive black holes: accretion, spin evolution, jets and winds
Abstract not available
- Speaker: Martin Bourne (IoA)
- Friday 03 May 2024, 11:30-12:30
- Venue: Ryle seminar room + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.