by Robert Schreiber
Berlin, Germany (SPX) Jul 19, 2024
An international team of researchers, led by PD Dr. Florian Peissker, has identified signs of an intermediate-mass black hole while studying a star cluster near the supermassive black hole SgrA* (Sagittarius A*) at the center of our galaxy.
Despite extensive research, only about ten intermediate-mass black holes have been discovered throughout the universe. These black holes, believed to have formed shortly after the Big Bang, serve as 'seeds' for the growth of supermassive black holes. The study, "The Evaporating Massive Embedded Stellar Cluster IRS 13 Close to Sgr A*. II. Kinematic structure," was published in The Astrophysical Journal.
The star cluster IRS 13, located 0.1 light years from the galactic center, displayed an unexpectedly orderly movement of its stars, contrasting with the anticipated random arrangement. This orderly pattern suggests two possibilities: IRS 13's interaction with SgrA* influences the stars' motion, and an internal factor helps maintain its compact shape.
Multi-wavelength observations using the Very Large Telescope, ALMA, and Chandra telescopes indicate that an intermediate-mass black hole could be responsible for IRS 13's compact structure. Characteristic X-rays and ionized gas rotating at several hundred km/s around the suspected black hole further support this hypothesis.
The high density of IRS 13, unparalleled by any known star cluster density in the Milky Way, also points to the presence of an intermediate-mass black hole. "IRS 13 appears to be an essential building block for the growth of our central black hole SgrA*," said Florian Peissker, first author of the study.
"This fascinating star cluster has continued to surprise the scientific community ever since it was discovered around twenty years ago. At first it was thought to be an unusually heavy star. With the high-resolution data, however, we can now confirm the building-block composition with an intermediate-mass black hole at the centre." Upcoming observations with the James Webb Space Telescope and the Extremely Large Telescope, currently under construction, are expected to provide further insights into the star cluster's dynamics.
Research Report:The Evaporating Massive Embedded Stellar Cluster IRS 13 Close to Sgr A*. II. Kinematic structure
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