- 3288 - BLACKHOLES - intermediate-mass blackholes? When a blackhole gobbles up a star, it produces what astronomers call a "tidal disruption event." The shredding of the star is accompanied by an outburst of radiation that can outshine the combined light of every star in the blackhole's host galaxy for months, even years.
--------------------- 3288 - BLACKHOLES - intermediate-mass blackholes?
- The Arizona Steward Observatory measures the X-rays emitted by a “tidal disruption event” to make the first measurements of both the blackhole's mass and spin. This Blackhole, J2150, is of a particular type, an intermediate-mass Blackhole, which has long eluded observation.
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- The fact that we were able to catch this blackhole while it was devouring a star offers a remarkable opportunity to observe what otherwise would be invisible. By analyzing the flare astronomers are able to better understand this category of blackholes, which may well account for the majority of blackholes in the centers of galaxies.
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- This flare did originate from an encounter between a star and an intermediate-mass blackhole. The intermediate blackhole is of particularly low mass weighing in at 10,000 times the mass of the sun.
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- The X-ray emissions from the inner disk formed by the debris of the dead star made it possible for astronomers to infer the mass and spin of this blackhole and classify it as an “intermediate“.
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- The centers of almost all galaxies that are similar to or larger in size than our Milky Way host central supermassive blackholes. These range in size from 1 million to 10 billion times the mass of our sun, and they become powerful sources of electromagnetic radiation when too much interstellar gas falls into their vicinity.
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- The mass of these blackholes correlates closely with the total mass of their host galaxies; that is, the largest galaxies host the largest supermassive blackholes.
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- Still astronomers know very little about the existence of blackholes in the centers of galaxies smaller than the Milky Way. It is challenging to discover central blackholes much smaller than 1 million solar masses.
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- The measurement of J2150's spin holds clues as to how blackholes grow. This blackhole has a fast spin, but not the fastest possible spin. The spin measurement allows astrophysicists to test hypotheses about the nature of “dark matter“. Dark matter may consist of unknown elementary particles not yet seen in laboratory experiments. Among the candidates are hypothetical particles known as “ultralight bosons“.
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- If those ultralight bosons particles exist and have masses in a certain range, they will prevent an intermediate-mass blackhole from having a fast spin.
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- New observations of tidal disruption flares might let astronomers fill in the gaps in the blackhole mass distribution. Most dwarf galaxies contain intermediate-mass blackholes, then they will dominate the rate of stellar tidal disruption. By fitting the X-ray emission from these flares to theoretical models, astronomers can conduct a census of the intermediate-mass blackhole population in the universe.
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- To do that more tidal disruption events have to be observed. That's why astronomers hold high hopes for new telescopes coming online soon, both on Earth and in space, including the “Vera C. Rubin Observatory“, also known as the “Legacy Survey of Space and Time“, or LSST, which is expected to discover thousands of “tidal disruption events” per year.
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- September 31, 2021 BLACKHOLES - intermediate-mass blackholes? 3284
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