2024/11/06 by Ning, Orion, Dessert, Christopher, Hong, Vi +1 · 2 citations
#FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Phenomenology (hep-ph) #Solar and Stellar Astrophysics (astro-ph.SR)
paper · doi:10.48550/arxiv.2411.05041
Low mass axion-like particles could be produced in abundance within the cores of hot, compact magnetic white dwarf (MWD) stars from electron bremsstrahlung and converted to detectable X-rays in the strong magnetic fields surrounding these systems. In this work, we constrain the existence of such axions from two dedicated Chandra X-ray observations of ∼40 ks each in the energy range ∼1 - 10 keV towards the magnetic white dwarfs (MWDs) WD 1859+148 and PG 0945+246. We find no evidence for axions, which constrains the axion-electron times axion-photon coupling to |gaγγ gaee| \lesssim 1.54 × 10-25 (3.54 × 10-25) GeV-1 for PG 0945+246 (WD 1859+148) at 95% confidence for axion masses ma \lesssim 10-6 eV. We find an excess of low-energy X-rays between 1 - 3 keV for WD 1859+148 but determine that the spectral morphology is too soft to arise from axions; instead, the soft X-rays may arise from non-thermal emission in the MWD magnetosphere.