[Astro] Seminar by Professor George Efstathiou

[Alfonso Aragon-salamanca (staff)]

Dear all,

In case you missed it in Ella's message yesterday, Professor George Efstathiou, one of the top cosmologists in the country and the world, is visiting us today and giving a seminar here in CAPT. See details below. I think it will be a very interesting seminar, so I recommend you attend if you can. Joining online is also possible.

Best wishes,

Alfonso


Tuesday 24th February at 1pm, A113 CAPT - Particle Cosmology and Gravity Seminar

George Efstathiou (Cambridge)

The Evidence for Dynamical Dark Energy


The Dark Energy Spectroscopic Instrument (DESI) collaboration has measured baryon acoustic oscillation (BAO) features over a wide range of redshifts with unprecedented precision. They argue that the data provide evidence for evolving dark energy, quoting 'significance' levels of 2.5-4.5 sigma depending on which additional data (CMB anisotropies and supernovae) are added to the BAO data. The favoured model of dynamical dark energy is unusual, requiring phantom-like behaviour at high redshift. I will present a different way of looking at the DESI data that provides simple and robust tests of consistency with the LCDM cosmology. I find no evidence for a deviation from LCDM and my analysis explains the degeneracy direction in the w_0-w_a plane found by the DESI collaborations. I will summarize some recent work on type Ia Supernova (SN) that supports my earlier claims that SN catalogues are not yet accurate enough to constrain models of dynamical dark energy.


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


Alfonso Aragón-Salamanca
Professor of Astronomy

School of Physics and Astronomy
University of Nottingham
Room B106b, Centre for Astronomy and Particle Theory
University Park
Nottingham, NG7 2RD, UK

+44 (0) 115 95 16230 | alfonso.aragon at nottingham.ac.uk<mailto:alfonso.aragon at nottingham.ac.uk>
URL: http://nottingham.ac.uk/physics/people/alfonso.aragon
General teaching enquiries physics-teaching at nottingham.ac.uk<mailto:physics-teaching at nottingham.ac.uk>

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