Scientists of Chicago and Fordem Universities in the United States studied three superhist X-ray sources (ULX) in the spiral galaxy NGC 891. Each of them emits more radiation of the X-ray range than one million suns on all wavelengths. The exact nature of this phenomenon remains a mystery. The results of the study that will help explain ULX published in the ARXIV journal.
Astronomers analyzed the data collected by the X-ray Observatory Chandra NASA and the XMM-Newton Space Agency of the European Space Agency. They were interested in the observation of the spiral galaxy with the NGC 891 bar, visible from the edge and at a distance of 30 million light years, because it contains three superhist X-ray sources – ULX-1, ULX-2 and ULX-3.
Specker of the ULX-1 source changed from 203 to 2016, and the shine curve decreased, especially from 2000 to 2003. Nevertheless, the source remained stable and did not change much over the observation time. His luminosity was 8.4 per 10 in the 39th degree of ERG per second. For comparison, the luminosity of the Sun is 3.8 per 10 in the 33rd ERG degree per second.
ULX-2 emitted a non-changing radiation stream, which was 20-50 percent stronger than the ULX-1. Finally, ULX-3 turned out to be the weakest source, and its luminosity was two 10 in the 39th degree of ERG per second. The radiation stream has decreased seven times from November 2016 to January 2017, which is why the source is no longer classified as supernators. At the moment it is closer to X-ray double stars – double systems, whose X-ray radiation is generated by a fall in the substance from the star to the compact object like a black hole or neutron star.
To explain the nature of all three sources, scientists simulated several scenarios that take into account the results of observations. They reviewed such options such as supernovable, tidal destruction event, accreting a source with super-endington luminosity and X-ray double stars. The first two sources are likely to be black holes weighing 50-80 suns, whose luminosity exceeds the Eddington limit (shows the magnitude of the radiation for the object in the equilibrium state of the honey gravity and radiation pressure). As for the third source of ULX-3, so far scientists have too little data in order to unambiguously judge its nature, although its luminosity corresponds to a black hole weighing 20 suns.