Thu 13 Mar 16:00: Reconstructing the History of the Milky Way Galaxy Using Stars
Astronomy of the Milky Way Galaxy has entered a transformative era. The Gaia mission and an ensemble of ground-based spectroscopic surveys are delivering element abundances and velocities for millions of stars. These data provide both an opportunity to deepen our understanding of galaxy formation and to test the “limits of knowledge.” There have been several surprises that have come out of the large stellar surveys and data-driven methodologies built to analyse them. We have learned that up to 1 in 100 stars in the disk are “abundance doppelgangers” – chemically identical but unrelated – limiting the prospect of reconstructing the disk’s star cluster building blocks. Furthermore, for stars in the disk, most of the element abundances measured for most of the stars can be predicted to a precision of better than 10 percent given only two key abundances. However, this is not the case for stars in the stellar halo. These findings frame how we can most effectively work with the data to turn photons into a quantified description of Galactic history and provide strong constraints on the star formation and mixing processes that have set the Galactic environment.
- Speaker: Melissa Ness, Research School of Astronomy and Astrophysics (RSAA), Australian National University, Canberra, Australia
- Thursday 13 March 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, IoA (tea at 3:30 pm).
- Series: The Eddington Lectures ; organiser: .
Mon 20 Jan 13:00: Fermion Creation by Cosmic Perturbations at 1-loop
Weyl spin 1/2 fermions, when minimally coupled to Einstein’s gravity, cannot be produced purely gravitationally in an expanding universe at tree level. However, this picture changes at the gravitational 1-loop level in the presence of cosmic perturbations, leading to a new and unavoidable mechanism for gravitational particle production. In this talk, I will explore the theory and phenomenological implications of this new effect.
- Speaker: Azadeh Maleknejad (King's College London)
- Monday 20 January 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Thomas Colas.
Fri 14 Mar 11:30: Title to be confirmed
Abstract not available
- Speaker: Leah Bigwood (IoA)
- Friday 14 March 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 21 Mar 11:30: Title to be confirmed
Abstract not available
- Speaker: Matt Grayling (IoA)
- Friday 21 March 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Mon 17 Mar 13:00: Title to be confirmed
Abstract not available
- Speaker: Giulia Cusin (Institut d'Astrophysique de Paris)
- Monday 17 March 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Louis Legrand.
Fri 31 Jan 11:30: Title to be confirmed
Abstract not available
- Speaker: Boris Bolliet (Cavendish)
- Friday 31 January 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 24 Jan 11:30: Determining Galaxy Kinematics and ISM conditions with the JWST/NIRSpec IFU
Massive, starbursting galaxies in the early Universe represent some of the most extreme objects in the study of galaxy evolution. Studies of their FIR emission with ALMA /NOEMA have revealed immense molecular gas reservoirs, high levels of star formation activity, and evidence for complex kinematics (e.g., rotation, merging, outflows). With the advent of the JWST /NIRSpec IFU , we may now investigate the ionised gas properties and kinematics on sub-kpc scales. Here, we detail the study of three such sources from the GA-NIFS survey: the SMG HFLS3 (z=6.34), the FIR -bright source HZ10 (z=5.65), and the LBG B1465666 (z=7.15). Using new NIR Spec/IFU data we present spectral fits, morpho-kinematic maps, and line ratio analyses for each. All sources are resolved into multiple discrete components, with spatial variations in ISM conditions that are explored through comparison to FIR observations.
- Speaker: Gareth Jones (Cavendish)
- Friday 24 January 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Fri 07 Feb 11:30: Title to be confirmed
Abstract not available
- Speaker: Eun-jin Shin (IoA)
- Friday 07 February 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.
Thu 30 Jan 16:00: AGN Feedback to Cosmology: eROSITA's Distinct Perspective on Large-Scale Structure
Abstract: Galaxy clusters, representing the peaks in the cosmic density field, serve as an independent and powerful tool for investigating the evolution of cosmic structures. The strategic identification of these clusters through multi-wavelength surveys is essential for advancing our understanding of gravitational theory, general relativity, and cosmological models. A significant milestone was achieved with the successful launch of eROSITA in July 2019. The German-built eROSITA X-ray telescope, on board the Russian-German Spectrum-RG (SRG) mission, operates within the 0.2-8 keV range and has produced the largest ICM -detected catalogs of galaxy clusters and groups through its first All-Sky Survey. With over 10,000 confirmed clusters, the survey is pivotal in refining cosmological parameters when combined with the data from optical surveys like DESI Legacy, DES , HSC, and KIDS . These parameters are constrained at a percentage level through the evolution of the cluster mass function, representing a significant leap forward, exhibiting a 5-9 times improvement compared to previous cluster surveys. In this talk, I will outline the constraints on fundamental cosmological parameters, neutrino masses, and general relativity derived from the first eROSITA All-Sky Survey. Additionally, I will present eROSITA’s significant detection of warm baryons within cosmic filaments identified by optical surveys and the implications for our understanding of AGN feedback in group-size haloes. I will summarize the value-added products made available to the science community by the eROSITA consortium’s data release.
- Speaker: Esra Bulbul
- Thursday 30 January 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Thu 20 Mar 16:00: Title to be confirmed
Title to be confirmed
- Speaker: Hannah Wakeford
- Thursday 20 March 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Thu 06 Mar 16:00: Title to be confirmed
Title to be confirmed
- Speaker: Evan O'Connor
- Thursday 06 March 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Thu 27 Feb 16:00: Title to be confirmed
Title to be confirmed
- Speaker: Ravit Helled
- Thursday 27 February 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Thu 20 Feb 16:00: Title to be confirmed
Title to be confirmed
- Speaker: Hagai Perets
- Thursday 20 February 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Thu 06 Feb 16:00: Title to be confirmed
Title to be confirmed
- Speaker: Natascha M. Foerster Schreiber
- Thursday 06 February 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Jan Scholtz.
Thu 23 Jan 16:00: Title to be confirmed
Title to be Confirmed
- Speaker: Mickael Rigault
- Thursday 23 January 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Thu 30 Jan 16:00: Title to be confirmed
Title to be confirmed
- Speaker: Esra Bulbul
- Thursday 30 January 2025, 16:00-17:00
- Venue: Hoyle Lecture Theatre, Institute of Astronomy.
- Series: Institute of Astronomy Colloquia; organiser: Matthew Grayling.
Mon 27 Jan 13:00: Primordial Black Holes - Positivist Perspective and Quantum Quiddity
Primordial black holes are black holes that may have formed in the early Universe. Their masses potentially span a range from as low as the Planck mass up to many orders of magnitude above the solar mass. This, in particular, includes those black holes recently discovered by LIGO /Virgo/KAGRA, and (part of) these may conceivably be of primordial origin. After a general introduction on primordial black holes, I review the observational hints for their existence—from a variety of lensing, dynamical, accretion and gravitational-wave effects. As I will show, all of these (over 20) may be explained by a single and simple unified model, naturally shaped by the thermal history of the Universe. If time permits, I will comment on vorticity, which we recently conjectured to be a novel feature of (near-extremally rotating) black holes, this possibly yielding the very first astrophysical observable for quantum effects in these compact bodies.
- Speaker: Florian Kühnel (LMU Munich)
- Monday 27 January 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Thomas Colas.
Mon 28 Apr 13:00: Title to be confirmed
Abstract not available
- Speaker: Nicole Righi (King's College London)
- Monday 28 April 2025, 13:00-14:00
- Venue: CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].
- Series: Cosmology Lunch; organiser: Thomas Colas.
Fri 28 Feb 11:30: Title to be confirmed
Abstract not available
- Speaker: Oliver Müller (EPFL)
- Friday 28 February 2025, 11:30-12:30
- Venue: Ryle Seminar Room, KICC + online.
- Series: Galaxies Discussion Group; organiser: Sandro Tacchella.