The axion signature of strange quark star in SGR 0501+4516

We study the axion effects on quark matter and quark-matter cores in strange quark magnetars using a three-flavor Nambu-Jona-Lasinio model to represent the charge-parity violating effects through the axion field. Here, axions decay to gamma rays in a very strong magnetic field, which the Fermi Large Area Telescope (Fermi-LAT), Imaging X-ray Polarimetry Explorer (IXPE), and XMM-Newton will be able to detect.