Tue 06 May 13:00: Title to be confirmed
Abstract not available
- Speaker: Matthew Johnson (Perimeter Institute and York University)
- Tuesday 06 May 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Thomas Colas.
Tue 10 Jun 11:15: Title TBC
Abstract TBC
- Speaker: Akeelah Bertram (Cavendish Arts Science Fellow)
- Tuesday 10 June 2025, 11:15-12:00
- Venue: Coffee area, Battcock Centre.
- Series: Hills Coffee Talks; organiser: Charles Walker.
Tue 20 May 13:00: Title to be confirmed
Abstract not available
- Speaker: Adrien La Posta (University of Oxford)
- Tuesday 20 May 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Louis Legrand.
Fri 23 May 11:30: Title to be confirmed
Abstract not available
- Speaker: Guido Roberts-Borsani (UCL)
- Friday 23 May 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Mon 19 May 15:00: Title to be confirmed
Abstract not available
- Speaker: Adrien La Posta (University of Oxford)
- Monday 19 May 2025, 15:00-16:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Louis Legrand.
Fri 13 Jun 11:30: Title to be confirmed
Abstract not available
- Speaker: Amandine Doliva-Dolinsky (Surrey)
- Friday 13 June 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 16 May 11:30: Title to be confirmed
Abstract not available
- Speaker: Girish Kulkarni (TIFR)
- Friday 16 May 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Tue 25 Feb 11:15: Exoplanet Detection with SPIRIT: Infrared CMOS Photometry and the Discovery of the Hot Neptune TOI-2407b
The SPECULOOS project is dedicated to the discovery of transiting exoplanets around ultracool dwarfs using high-precision ground-based observations. To enhance sensitivity to these cool stars, we have implemented SPIRIT , a new infrared detector utilizing CMOS technology instead of traditional CCDs. In this talk, I will present my work on developing the data pipeline for SPIRIT and optimizing its performance for detecting exoplanet transits. I will also highlight the discovery of TOI -2407b, a Neptune-like planet observed with this system.
- Speaker: Clàudia Janó Muñoz (University of Cambridge)
- Tuesday 25 February 2025, 11:15-12:00
- Venue: Coffee area, Battcock Centre.
- Series: Hills Coffee Talks; organiser: Charles Walker.
Mon 24 Feb 13:00: Total derivatives in cosmological perturbations: implications for decoherence and Bell violation
We examine the role of total time derivatives (boundary terms) in the action of cosmological perturbations and their impact on momentum-space entanglement, including the processes of decoherence and two-mode squeezing. We also discuss the necessity of considering such terms from several perspectives: the well-defined variational principle in gravity, the integration-by-parts procedure in cosmological perturbations and the WKB limit of the Wheeler-DeWitt equation. Finally, we explore their relevance in a proposed cosmological Bell test utilizing momentum-space entanglement, suggesting a possible window for Bell violation in minimal single-field inflation.
References: 2405.07141, 2305.08071 and 2207.04435
- Speaker: Chon Man Sou 蘇俊文 (Tsinghua U., Beijing)
- Monday 24 February 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Thomas Colas.
Tue 18 Feb 13:00: TOI-2407b: A hot Neptune in the Neptune Desert discovered with the SPIRIT Infrared Detector
The discovery and characterization of exoplanets around ultracool dwarfs require precise ground-based observations across visible and infrared wavelengths. In this talk, I will present the discovery of TOI -2407b, a Neptune-sized planet located in the Neptune desert—a sparsely populated region of parameter space for close-in exoplanets. This detection was made using SPIRIT , a novel infrared CMOS detector designed to enhance sensitivity to cool stars. I will discuss the role of SPIRIT in improving exoplanet transit observations, the development of its data pipeline, and the implications of TOI -2407b for our understanding of planet formation and evolution in the Neptune desert.
- Speaker: Clàudia Jano Muñoz (Cavendish)
- Tuesday 18 February 2025, 13:00-14:00
- Venue: Ryle seminar room + ONLINE - Details to be sent by email.
- Series: Exoplanet Seminars; organiser: Dr Dolev Bashi.
Fri 21 Feb 13:00: Free conformally-rescaled hyperboloidal evolution: status and applications
Gravitational wave radiation is only unambiguously defined at future null infinity – the location in spacetime where light rays arrive and where global properties of spacetimes can be measured. Reaching future null infinity is thus very important for extracting correct waveforms. A convenient way to include it in numerical relativity simulations is via hyperboloidal foliations. I will focus on conformal compactification as method to implement free hyperboloidal evolution, in the BSSN / conformal Z4 formulations. After illustrating its advantages, I will report on some ongoing applications in spherical symmetry: an extension to include the Maxwell equations, scattering simulations on a given background, and wave equation(s) evolved on some FLRW -type spacetimes with time-dependent scale factor. I will conclude giving an update on ongoing work in 3D evolutions.
- Speaker: Alex Vañó-Viñuales (IST Lisbon)
- Friday 21 February 2025, 13:00-14:00
- Venue: Potter room.
- Series: DAMTP Friday GR Seminar; organiser: Daniela Cors.
Fri 09 May 11:30: Title to be confirmed
Abstract not available
- Speaker: Girish Kulkarni (TIFR)
- Friday 09 May 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 21 Feb 11:30: Galactic Archaelogy in the Gaia era: a surprising population of very metal-poor stars in the Milky Way disc
Abstract not available
- Speaker: Federico Sestito (Hertfordshire)
- Friday 21 February 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Tue 04 Mar 11:15: Cygnus X-3 in 2024: many giant radio flares!
Cygnus X-3 is a `high mass X-ray binary’, which was first detected in the early days of X-ray astronomy, in 1966. It is also seen in the radio and the infra-red (but not optically due to obscuration). The emission is due to accretion from the companion star onto the compact source, thought to be a Wolf-Rayet star and a black hole respectively. It occasionally shows giant fares, and has been monitored—approximately daily—for several years with the Arcminute Microkelvin Image (AMI) at Lord’s Bridge, SW of Cambridge. During 2022 and 2023 was placid, with little variation in its radio (or X-ray) emission, but in 2024 it showed five giant radio flares, brightening from a few mJy to > 10 Jy over a few days.
- Speaker: Prof. Dave Green (Cavendish Astrophysics)
- Tuesday 04 March 2025, 11:15-12:00
- Venue: Martin Ryle Seminar Room, Kavli Institute.
- Series: Hills Coffee Talks; organiser: Charles Walker.
Fri 11 Apr 11:30: Title to be confirmed
Abstract not available
- Speaker: Emmy Escott (Durham)
- Friday 11 April 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Wed 19 Feb 13:40: Probing the early history of the Milky Way through ancient carbon-rich stars
The oldest, most metal-poor stars we find in the Milky Way today were born in pristine environments in the early Universe. These local, ancient stars contain unique clues about the First Stars and the early formation and evolution of our Galaxy. At low metallicity, many stars have been found to be enhanced in carbon, coming in two main types: some contain the fingerprints of the First Stars and others have experienced binary interaction with an evolved companion. I recently built a homogeneous sample of C-rich metal-poor stars using the Gaia XP spectra, employing a neural network and a dedicated training sample. I will present this recent paper and discuss how the change in frequency of C-rich stars with Galactic environment relates to globular clusters and clustered star formation in the early Universe.
- Speaker: Anke Ardern-Arentsen / IoA
- Wednesday 19 February 2025, 13:40-14:05
- Venue: The Hoyle Lecture Theatre + Zoom .
- Series: Institute of Astronomy Seminars; organiser: Xander Byrne.
Tue 11 Mar 13:00: Title to be confirmed
Abstract not available
- Speaker: Paul Huet (Paris Observatory)
- Tuesday 11 March 2025, 13:00-14:00
- Venue: Hoyle Committee Room - Details to be sent by email.
- Series: Exoplanet Seminars; organiser: Dr Dolev Bashi.
Mon 17 Feb 13:00: Explainable deep learning models in cosmology
Machine learning has significantly improved the way cosmologists model and interpret cosmological data; yet, its “black box” nature often limits our ability to trust and understand its results. In this talk, I will present an explainable deep learning framework designed to rely on a minimal set of physically interpretable parameters which describe the data. I will first discuss applications to dark matter halos, demonstrating how these neural networks can be used to model their final properties — such as their density profiles — and connect them to the underlying physics. Additionally, I will present applications to the cosmic microwave background, revealing to which parameters the CMB temperature power spectrum is sensitive in the context of early dark energy models.
- Speaker: Luisa Lucie-Smith (University of Hamburg)
- Monday 17 February 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Thomas Colas.
Mon 17 Feb 13:00: Title to be confirmed
Abstract not available
- Speaker: Luisa Lucie-Smith (University of Hamburg)
- Monday 17 February 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Thomas Colas.
Mon 17 Feb 14:00: Making waves in Stars: Bridging modern asteroseismology and numerical simulations
Stars and their evolution underpin most of modern astrophysics, enriching the galaxy with heavy elements and producing the progenitors of gravitational wave sources. Yet modern asteroseismology has shown that standard 1D stellar evolution models, used widely in astrophysics fall short when confronted with these detailed observations. The discrepancies lie in the 1D treatment of 3D processes, such as convective overshoot, waves and magnetism. In this talk I will review some of the important results from asteroseismology, my groups work over the years on these processes and the various ways in which we can make contact with the observations and (possibly) improve 1D models.
- Speaker: Tamara Rogers (Newcastle)
- Monday 17 February 2025, 14:00-15:00
- Venue: MR14 DAMTP and online.
- Series: DAMTP Astrophysics Seminars; organiser: Loren E. Held.