profile image

Francesca Day

Graduate Student

I am interested in axion phenomenology and in new physics searches with X-ray telescope observations. See here for a full list of my publications. Outside of research, I am a science comedian, which you can read about here.

I have taught mechanics, special relativity, subatomic physics, theoretical physics and computing at undergraduate level. I have also tutored graduate level quantum field theory and conducted admissions interviews.

Our most recent work (1608.01684 and 1605.01043) searches for new physics using ultra-deep X-ray observations of the central Active Galactic Nucleus of the Perseus galaxy cluster. We find two anomalies at high significance that we are unable to account for through conventional instrumental or astrophysical processes. These could be signals from axion-photon mixing, or from a two state Fluorescent Dark Matter model. In particular, we find a dip at 3.5 keV in the spectrum of the AGN. This is at the same energy as the long-standing 3.5 keV line observed in galaxy clusters. In a Fluorescent Dark Matter model, both of these features are explained, and the recent non-observation of the 3.5 keV line by Hitomi is fully consistent.