12:00–1:00 pm ERC 401
Raymond T Co , University of Michigan
"X-ray Search for Axions from Nearby Isolated Neutron Stars"
Host: Yiming Zhong
We performed a search for axion-like particles (ALPs) in the nearby isolated neutron stars and interpreted the recently observed excess in X-ray by an axion model. These ALPs can be produced from the hot cores of the neutron stars at temperatures around 10^8 K and be converted into X-ray photons within the magnetosphere of the neutron stars. The dominant production modes are the nucleon bremsstrahlung and Cooper pair-breaking-formation processes. These ALPs and the produced photons carry energies of order the core temperature or the superfluid gaps and are therefore much hotter than the surface temperature of around 10^6 K. X-ray dim isolated neutron stars are excellent targets due to low background in the signal range of 1-100 keV. We fit the axion model to an X-ray excess in 2-8 keV observed by XMM-Newton and Chandra and discuss prospects of confirming or ruling out the axion interpretation by future measurements of NuSTAR.