Talks

Axions are some of the best-motivated beyond the Standard Model particle candidates at present. These ultralight particles may account for the cosmological dark matter and explain other outstanding problems in nature, such as the strong-CP problem; they also are now known to emerge generically in string theory.  Axions are expected to couple ultra-weakly with ordinary matter, which complicates their detection. However, thanks to recent theoretical, experimental, and observational progress these particles may be discovered or ruled out within the near future. I will review some of the recent ideas that may soon play a role in axion discovery, including computing the evolution of axions in the early universe using supercomputers and novel observational signatures of axions that emerge in extreme astrophysical environments such as supernovae.

Studying low-redshift analogues of phenomena in the early Universe is an established method for getting a closer look at intriguing physics. However, determining when a local analogue functions well to represent distant systems, and what limitations need to be kept in mind, can be challenging. Notably, low redshift examples often reveal complexity that gets hidden when looking at high redshift objects. For distant objects, limited spatial and spectral resolution and reduced sensitivity can lead to extraordinary claims that do not hold up over time. I'll discuss specific examples of local analogues that reveal complexity that should be considered when studying distant objects, focussing on local compact galaxy groups and super Eddington-accreting active galactic nuclei.