[Astro] [CAPT] CAPT Weekly bulletin (w/c 09-03-26)

[Ella Batchelor (staff)]

Monday 9th March at 1.30pm, A113 CAPT – Theoretical Physics Student Seminar

Benjamin Muntz

An introduction to CFTs - Part 1

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Tuesdays at 11am, CAPT Foyer – Astro Coffee

Tuesdays at 11.30am, A113 CAPT – Astronomy Journal Club



Tuesday 10th March at 1pm, C12 Physics – Particle Cosmology and Gravity Seminar

Basudeb Dasgupta  (Tata Institute of Fundamental Research, Mumbai, India)

Probing Dark Matter with Gravitational Waves from Mergers (online)


Gravitational waves open new avenues to study dark matter through the dynamics of compact objects. In this talk, we will outline two examples of this new rapidly developing field. First, we will discuss how dark matter captured by neutron stars can induce their collapse into low-mass black holes, with their mergers detectable by current and future observatories. Such events probe dark matter–nucleon interactions at cross-sections below the neutrino floor and masses spanning GeV to PeV. Existing LIGO/Virgo data already yield strong bounds, while future detections could reveal dark core collapse and account for puzzles such as the missing pulsars near the Galactic Center. In the second half, I will discuss a more model-independent probe using compact binaries near galactic centers, which can confirm or rule out parsec-scale density spikes and may be used to constrain broad classes of dark matter models.



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 11th March at 2pm, A113 CAPT – Particle Cosmology and Gravity Seminar

John T Giblin  (Kenyon College)

Primordial Black Holes from Cosmology


Primordial black holes (PBH) are formed when cosmic-scale over-densities collapse.  Unlike astrophysical black holes--formed in the aftermath of large stars--PBH masses are set by the size of the cosmic horizon and can therefore form at any mass range.  Among the mechanisms that would allow for such large horizon-scale overdensities is cosmic preheating.  In this talk I will discuss the first simulations that show the formation of primordial black holes in the context of so-called kinetic preheating, a proof-of-concept that PBH can be formed from cosmological processes.  I will also discuss several scenarios in which PBH are not formed and speculate on why some models are successful and some are not.



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



Wednesday 11th March at 3pm, C14 Physics – Postgraduate Poster Competition
The competition is sponsored by Cerca Magnetics. Posters will be judged by representatives from Cerca Magnetics and by staff from the school. Public viewing is from 3-4pm, with prize-giving at around 4pm.

Soft drinks and snacks will be provided. All staff and students are encouraged to attend.

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Thursday 12th March at 1pm, A113 CAPT – Astronomy Lunch Talk

Ke Ma

Constraining the silicon abundance in the IGM by modelling the Lyα – Si III correlations



The one-dimensional Lyman-α Forest power spectrum (P1D) serves as an important probe of the IGM and cosmological parameters. However, contamination from Si III absorption lines embedded within the Lyα forest introduces a significant systematic uncertainty in P1D measurements. To better model and mitigate this effect, we performed a detailed analysis of Si III absorption and its impact on the P1D using the Sherwood-Relics hydrodynamical simulation suite. We identify several effects that were not captured in earlier studies, largely due to limitations in spectral resolution at the time. These effects are also present in the more recent DESI measurements. To address them, we develop a new analytical fitting function that incorporates previously neglected physical ingredients. The model is validated against multiple simulated datasets across redshifts 2.2 < z < 5.0 and wavenumbers k < 0.2 s/km (See arXiv:2509.08613). Applying this model to eBOSS and DESI observations reveals a Si III signal stronger than expected from forward modeling based on published Si abundance constraints. This might point to a new way to constrain the metal abundance in the IGM.



Thursday 12th March at 2.45pm, A113 CAPT – Particle Cosmology Journal Club

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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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