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Stellar Devastation on a Massive Scale: Black Holes Destroy Thousands of Stars To Fuel Growth

When a star strays too close to a black hole, intense tides break it apart into a stream of gas. This artist’s animation shows some of these remains surrounding the black hole as a disk of debris. Credit: NASA’s Goddard Space Flight Center

  • Astronomers have found evidence for the destruction of thousands of stars in multiple galaxies, using NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. It's vision is "To discover and expand knowledge for the benefit of humanity."” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NASA’s Chandra X-ray Observatory.
  • Growing black holes within dense stellar clusters are thought to be responsible for this large-scale devastation.
  • This process could account for “intermediate mass black holes” through the runaway growth of stellar-mass black holes.
  • The new study involved the observations of over a hundred galaxies with Chandra.

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A new survey of over 100 galaxies by NASA’s Chandra X-ray Observatory has uncovered signs that black holes are demolishing thousands of stars in a quest to pack on weight. The four galaxies shown in the graphic below are among 29 galaxies in the sample that showed evidence for growing black holes near their centers. X-rays from Chandra (blue) have been overlaid on optical images from NASA’s Hubble Space Telescope of the galaxies NGC 1385, NGC 1566, NGC 3344, and NGC 6503. The boxes that appear in the image at the bottom of this article show the location of the burgeoning black holes.

These four galaxies are part of a large survey of more than 100 galaxies conducted by Chandra that looked for evidence of growing black holes. A new study uncovered evidence that stellar-mass black holes in these dense environments are ripping apart multiple stars, and then using their debris to fuel their growth. The Chandra results provide one pathway for the creation of “intermediate mass black holes,” a class that are bigger than the stellar-mass variety but smaller than supermassive black holes. For each of these galaxies, Chandra data are shown with optical images from the Hubble Space Telescope. Credit: X-ray: NASA/CXC/Washington State Univ./V. Baldassare et al.; Optical: NASA/ESA/STScI

These new results point to a relatively violent path for at least some of these black holes to reach their present size — stellar destruction on a scale that has rarely if ever been seen before.

Astronomers have made detailed studies of two distinct classes of black holes. The smaller variety are “stellar-mass” black holes that typically weigh 5 to 30 times the mass of the Sun. On the other end of the spectrum are the supermassive black holes that live in the middle of most large galaxies, which weigh millions or even billions of solar masses. In recent years, there has also been evidence that an in-between class called “intermediate-mass black holes” (IMBHs) exists. The new study with Chandra could explain how such IMBHs are made through the runaway growth of stellar-mass black holes.

One key to making IMBHs may be their environment. This latest research looked at very dense clusters of stars in the centers of galaxies. With stars in such close proximity, many stars will pass within the gravitational pull of black holes in the centers of the clusters. Theoretical work by the team implies that if the density of stars in a cluster — the number packed into a given volume — is above a threshold value, a stellar-mass black holeA black hole is a place in space where the pull of gravity is so strong not even light can escape it. Astronomers classify black holes into three categories by size: miniature, stellar, and supermassive black holes. Miniature black holes could have a mass smaller than our Sun and supermassive black holes could have a mass equivalent to billions of our Sun.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>black hole at the center of the cluster will undergo rapid growth as it pulls in, shreds and ingests the abundant neighboring stars in close proximity.

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Of the clusters in the new Chandra study, the ones with density above this threshold had about twice as many growing black holes as the ones below the density threshold. The density threshold depends also on how quickly the stars in the clusters are moving.

The process suggested by the latest Chandra study can occur at any time in the universe’s history, implying that intermediate-mass black holes can form billions of years after the Big BangThe Big Bang is the leading cosmological model explaining how the universe as we know it began roughly 13.8 billion years ago.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Big Bang, right up to the present day.

Credit: X-ray: NASA/CXC/Washington State Univ./V. Baldassare et al.; Optical: NASA/ESA/STScI

A paper describing these results was accepted and appears in The Astrophysical Journal. The authors of the study are Vivienne Baldassare (Washington State University), Nicolas C. Stone (Hebrew University in Jerusalem, Israel), Adi Foord (Stanford University), Elena Gallo (University of Michigan), and Jeremiah Ostriker (Princeton UniversityFounded in 1746, Princeton University is a private Ivy League research university in Princeton, New Jersey and the fourth-oldest institution of higher education in the United States. It provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences, and engineering.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Princeton University).

Reference: “Massive black hole formation in dense stellar environments: Enhanced X-ray detection rates in high velocity dispersion nuclear star clusters” by Vivienne F. Baldassare, Nicholas C. Stone, Adi Foord, Elena Gallo and Jeremiah P. Ostriker, 14 April 2022, The Astrophysical Journal.
DOI: 10.3847/1538-4357/ac5f51

NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Source: SciTechDaily