Center for Theoretical Physics of the Universe (CTPU-PTC)

Axion Archaeology -- Echos from Ancient Supernova Remnants

by Dr Chen Sun (Los Alamos)


Stimulated decays of axion dark matter, triggered by a source in the
sky, could produce a photon flux along the continuation of the line of
sight, pointing backward to the source. The strength of this so-called
axion “echo” signal depends on the entire history of the source and
could still be strong from sources that are dim today but had a large
flux density in the past, such as supernova remnants (SNRs). This echo
signal turns out to be most observable in the radio band. In this
talk, I will discuss the sensitivity of radio telescopes such as the
Square Kilometer Array (SKA) to echo signals generated by SNRs that
have already been observed. I will also show projections of detection
reach for signals from old “ghost” SNRs which were very bright in the
past but are so dim that they haven’t been observed now.