Speaker
Description
Electromagnetic fields of pulsars can source coherent axion signals at their rotational frequencies, which can be detected by laboratory experiments—pulsarscopes. As a promising case study, we model axion emission from the well-studied Crab pulsar, which would yield a signal at $f \approx 29.6$ Hz and be present regardless of whether the axion contributes to the dark matter abundance. We estimate the sensitivity of future axion dark matter detection experiments such as DMRadio-GUT, Dark SRF, and CASPEr to the pulsar-sourced axion signal, assuming different magnetosphere models to bracket the uncertainty in astrophysical modeling. For example, the Dark SRF experiment could probe axions with any mass below $10^{-13}$ eV down to $g_{a\gamma\gamma} \sim 3 \times 10^{-13}$ GeV$^{-1}$ with one year of data, assuming the vacuum magnetosphere model. The projected sensitivity may be degraded depending on the extent to which the magnetosphere is screened by plasma. The promise of pulsar-sourced axions as a clean target for direct detection experiments motivates dedicated simulations of axion production in pulsar magnetospheres.
