Searching for Axionlike Particles with X-Ray Observations of Alpha Centauri
Using X-ray observations of the Alpha Centauri star system, we have set the tightest limits to date on axion-like particles (ALPs), hypothetical particles that interact with light. A large number of keV ALPs produced in stellar cores, are gravitationally trapped in the orbits of stars and subsequently decay into two photons, which may be observed as the X-ray line at frequency corresponding half of the mass. By analyzing data from the Chandra and eROSITA telescopes in the 0.2–10 keV range, our team searched for the signal of ALP decay. While no signals are found, our results provide the most stringent constraints on ALP-photon interactions, improving previous limits by up to two orders of magnitude for ALPs (with mass from 0.1 keV to 3keV). These findings advance the search for ALPs and open the door for future high-resolution X-ray observations to explore their fundamental nature.