K. Perez Colloquium: Probing the Dark Universe with X-ray Optics

Dark matter particles could be unstable and decay, annihilate with each other, or subtly alter the processes within stellar interiors, imprinting characteristic signals in astrophysical observations. In this talk, I will describe how relatively low-cost focusing X-ray telescope technology opens new sensitivity to rare dark matter signals. I will introduce how thermal-slumped glass optics — in which thousands of mirrors are mounted into nested shells via precision machining — helped the NuSTAR satellite mission deliver leading sensitivity to light dark matter candidates, in particular sterile neutrinos and axions. I will then discuss how similar focusing X-ray optics are now being developed for the International Axion Observatory (IAXO), providing leading sensitivity to axions and axion-like particles (ALPs) across a wide mass range.