Thesis off-cuts: the reproducibility crisis in cosmology

As we frequently hear1, we're now in the precision era of cosmology. What this really means is that we're in the era of measuring things really well, and we're getting really good at measuring things because we keep building ever more enormous and powerful telescopes. I remember attending the STFC Introductory Summer School on Astronomy …

Continue reading Thesis off-cuts: the reproducibility crisis in cosmology

Thesis off-cuts: how special is our place in the Universe?

Thanks to many hundreds of people making dedicated observations of the sky over many decades, we know that the majority of our Universe is comprised of two substances: dark matter and dark energy. Dark matter is an unknown type of matter, referred to as "dark" because it does not interact electromagnetically, meaning that it doesn't …

Continue reading Thesis off-cuts: how special is our place in the Universe?

The distance duality relation

The distance duality relation tells us how, assuming that photons propagate on null geodesics in a pseudo-Riemannian spacetime and that their number is conserved, luminosity and angular diameter distances are related, via where dL is the luminosity distance, dA the angular diameter distance and z the redshift. This relation was introduced by Etherington in 1933, …

Continue reading The distance duality relation

Thesis off-cuts: the ancient history of general relativity

I have recently been thinking a lot about what introductory and background material I want to include in my PhD thesis, as my self-imposed December deadline continues to hurtle towards me at an alarming speed. Concurrent with this thinking, I've also recently been enjoying a fantastic book called The Poincaré Conjecture by Donal O'Shea, all …

Continue reading Thesis off-cuts: the ancient history of general relativity

Paper day! Madrid week seven

Today my first paper as first author came out on the arXiv! You can check it out here: https://arxiv.org/abs/2002.10449. In this work, we reconstruct a coupling function between dark matter and vacuum energy. Such models are generally motivated as solution to problems such as the Hubble tension, so we were keen to update our previous …

Continue reading Paper day! Madrid week seven

Constraints on the interacting vacuum — geodesic CDM scenario

At the very end of February, I published my first paper. In this post, I want to provide a brief, non-technical overview of what we* were doing in this work and the results we found. The manuscript is currently under review at MNRAS but you can view the preprint here: http://www.arxiv.org/abs/1902.10694. The aim of this …

Continue reading Constraints on the interacting vacuum — geodesic CDM scenario