[Astro] [CAPT] CAPT Weekly Bulletin (w/c 08-06-26)

[Ella Batchelor (staff)]

Monday 8th June at 3pm, A113 CAPT – Theoretical Physics Student Seminar

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Tuesdays at 11am, CAPT Foyer – Astro Coffee

Tuesdays at 11.30am, A113 CAPT – Astronomy Journal Club



Tuesday 9th June at 1pm, C12 Physics – Particle Cosmology and Gravity Seminar

Sayyed Farbod Rassouli (UoN)

Volume as Time: Boundary Dynamics Near Black Hole Horizons


Different notions of time arise from different choices of observer. In cosmological settings, a particularly natural choice is the spacetime volume, which is conjugate to the cosmological constant. This gives rise to unimodular time, deparametrizing the Wheeler–DeWitt equation into a Schrödinger-like evolution equation. I will first explain how this construction appears in arbitrary dimension, with particular emphasis on the four-dimensional case.

As an explicit Holographic realisation, I will then focus on near-extremal black holes, whose low-energy throat dynamics is universally described by Jackiw–Teitelboim gravity. In this setting, promoting the vacuum cosmological constant to a dynamical top-form degree of freedom provides a bulk clock in the Henneaux–Teitelboim sense. Holographically, this modifies the usual Schwarzian boundary dynamics by coupling it to an additional U(1) phase mode, reproducing the universal low-energy structure familiar from complex SYK. Finally, I will show that the resulting boundary theory can be rewritten as a (0+1) dimensional observer action, making explicit the relation between the bulk volume clock and its holographic boundary counterpart.



Link to join: https://teams.microsoft.com/l/meetup-join/19%3ameeting_OGM3OTk5NzQtZWEwZS00ZmUyLTk3MGUtZjFhY2M5OTU2MjI1%40thread.v2/0?context=%7b%22Tid%22%3a%2267bda7ee-fd80-41ef-ac91-358418290a1e%22%2c%22Oid%22%3a%22f3250584-4b5f-48fa-a897-08e77f2246b7%22%7d
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Wednesday 10th June at 3.45pm, A113 Physics – Astronomy Seminar

Vatsal Panwar (Birmingham)

Chemical compositions and atmospheric dynamics of exoplanet atmospheres at high spectral resolution



Exoplanet atmospheres are tracers of the formation and evolution pathways that sculpt planetary systems. Doppler spectroscopy using ground-based high-resolution spectrographs has emerged as one of the most promising recent techniques to characterise the atmospheres of planets in physical regimes beyond the solar system. Recent studies of gas-giant exoplanets have yielded extraordinary precision on the thermal and chemical properties of their atmospheres, providing insights into their extraordinary formation histories and climates. I will give an overview of the current state of the field of high-resolution spectroscopy for exoplanet atmospheres, introducing the fundamentals of the technique, and covering the latest key developments and synergies with other popular techniques for exoplanet atmospheric characterisation. With this background, I will discuss some recent work on characterising the dayside atmospheres of hot to ultra-hot Jupiter exoplanets in the near-infrared using VLT/CRIRES+ and Gemini/IGRINS. I will also discuss the near-future prospects for high-resolution spectroscopy in improving the detail and precision in our measurements of exoplanet atmospheres as we approach the next leap in planet detection and characterisation this decade using PLATO and the Extremely Large Telescope.

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Thursday 11th June at 1pm, A113 CAPT – Astronomy Lunch Talk

Guillaume Hewitt

No hidden monsters and Survival of the faintest: Probing the quenching pathways of high- and low-mass PSBs


Quenching models for massive galaxies frequently invoke AGN feedback as a primary mechanism. However, the lack of evidence for excess AGN activity in recently quenched post-starburst galaxies (PSBs) may suggest that AGN are not the dominant quenching mechanism, that AGN activity is short-lived and does not extend into the PSB phase, or that the AGN are heavily obscured. If obscured AGN are present in PSBs, they should still be detectable through hot-dust emission in the infrared. In this talk, I present results on the mid-infrared emission of PSBs in the PRIMER-UDS field.

I will also present preliminary results on the environmental dependence of low-mass PSBs across the PRIMER fields, providing insight into their dominant quenching pathways, as well as evidence for a potentially distinct population of ultra-low-mass PSBs.



Thursdays at 3pm, A113 CAPT – Particle Cosmology Journal Club

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Friday 12th June at 1pm, A113 CAPT – Astronomy Seminar

Shuang Zhou

Internal vs. External Drivers: The Role of Feedback and Environment in Galaxy Chemical Evolution

In this talk, I will present our recent works on galaxy chemical evolution from the local Universe (SDSS-IV/MaNGA) to intermediate redshift (COSMOS-WALL/LEGA-C), aiming to understand the roles of feedback and environment in shaping galaxy evolution. We reconstruct the star formation and chemical enrichment histories of galaxies in a self-consistent framework, and investigate how the interplay between gas accretion and outflows drives their evolution. In particular, we will discuss the roles of feedback from active galactic nuclei and supernovae, as well as environmental processes in regulating these mechanisms. Finally, I will highlight how forthcoming spectroscopic surveys such as 4MOST and WEAVE will provide key data to further test and extend these scenarios.



Fridays at 4pm, CAPT Foyer – CAPT Cakes

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If you have any events/visitors you would like included in next week’s bulletin, please let me know.

Best wishes

Ella

Ella Batchelor (she/her)
Administrator

School of Physics & Astronomy

University of Nottingham
A112a Centre for Astronomy & Particle Theory
University Park
Nottingham, NG7 2RD

+44 (0) 115 74 86778 |  nottingham.ac.uk<http://nottingham.ac.uk/>

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