arXiv: Astronomers observe flash from ultra-bright X-ray pulsar Astronomers at the Physical Institute of India conducted detailed observations of the ultra-luminous X-ray pulsar Swift J0243.6+6124 and discovered unusual features in the object’s behavior. The research results were published on the preprint server arXiv. Ultraluminous X-ray sources (ULXs) are point sources in the sky that are extremely bright in the X-ray range, each emitting more radiation than a million suns at all wavelengths. These objects were previously thought to be black holes, but recent observations have shown that some ULXs emit coherent pulsations and are actually ultra-bright X-ray pulsars. Ta. Swift J0243.6+6124 was discovered by NASA’s Swift spacecraft during his powerful X-ray burst in 2017-2018. It is believed to be the first galaxy ULX because its X-ray brightness is on the order of 120 ergs per second. This object has a companion star that provides material. From June to September 2023, Swift J0243.6+6124 entered a burst phase indicating a change in the neutron star’s momentum profile. Scientists have discovered that the pulsar has three different accretion modes. Previously, an international group of astronomers revealed the nature of a mysterious cosmic source of ultra-high energy radiation, 2FHL J1745.1-3035. This object is most likely a powerful pulsar wind nebula, which forms when a pulsar’s charged particle wind collides with its surroundings.