Joint cosmology seminar at MIT online:

Tuesday, February 8, 2022, 2:30 pm
{\large\sf Zoom link will be distributed to joint cosmology seminar mailing list. See\\ to join.\\}
Massachusetts Institute of Technology

Axion Production in Pulsar Magnetosphere Gaps

Ani Prabhu


Axions and other pseudoscalar particles couple to electromagnetism through the $E\cdot B$ operator. This coupling is responsible for interconversion between axions and photons as well as production of axions by electromagnetic fields. In this talk I will show that pulsars are very efficient axion factories. Pulsar magnetospheres admit non-stationary vacuum gaps that are characterized by large $E\cdot B$. These gaps play an important role in plasma generation, electromagnetic wave emission and, as I will discuss, axion production. The local density of axions produced in gaps can exceed the ambient dark matter density by several orders of magnitude. A fraction of these axions may convert to photons, giving rise to broadband radio signals. Dedicated observations of nearby pulsars with radio telescopes and interferometers can probe axion-photon couplings that are a few orders of magnitude lower than current astrophysical bounds. I will also comment on other astrophysical/cosmological settings that can source axions through the $E\cdot B$ operator.