Researchers from more than a dozen institutions analysed data from over 1,600 galaxies collected during more than 20 years of the federally funded Chandra mission. The galaxies ranged from very large systems down to dwarf galaxies. The study was published in The Astrophysical Journal.
The team found that about 30% of dwarf galaxies likely host supermassive black holes, compared with more than 90% of massive galaxies similar to the Milky Way. Many massive galaxies show bright X-ray sources at their centres, a sign of material heating as it falls onto a black hole. Smaller galaxies — those with masses less than 3 billion suns — usually lacked these unambiguous X-ray signals; by comparison the Milky Way has a mass of around 60 billion suns.
Researchers considered two explanations and concluded both play a role: smaller black holes accrete less gas and are fainter in X-rays, and, beyond that, many low-mass galaxies may simply not host central black holes. The result gives clues about how the largest black holes first formed, and future observations such as the Laser Interferometer Space Antenna planned for 2035 could test the idea. Funding uncertainties for large missions may affect such follow-up work.
Difficult words
- galaxy — A large system of stars and matter.galaxies
- dwarf — A much smaller type of galaxy.
- supermassive — Extremely large in mass, especially for black holes.
- accrete — To take in gas or other material.
- unambiguous — Clear and not open to more than one interpretation.
- funding — Money provided to pay for projects or research.
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Related articles
Searching for Life on Exoplanets
Since a 1995 discovery, astronomers have found over 4,000 exoplanets. Scientists study biosignatures and technosignatures to learn if life or technology exists elsewhere. A NASA grant supports Adam Frank's work on technosignatures.
New isotope evidence on the Moon’s origin
A new study finds that the object that hit early Earth and formed the Moon—called Theia—likely formed closer to the Sun. Researchers used isotopes from Earth rocks, Apollo samples and meteorites to reach this conclusion.
Study: Many mini‑Neptunes may have solid surfaces
A University of Chicago study using JWST data and computer models finds many mini‑Neptunes might have solid surfaces instead of global magma oceans, because heavy atmospheres can create extreme pressure at the surface.
Webb finds an unusual planet orbiting a pulsar
Scientists using the James Webb Space Telescope observed a strange exoplanet with a helium–carbon atmosphere, soot clouds and possible diamond formation. The planet orbits a fast-spinning pulsar and challenges known formation theories.
New analysis: Titan may have a slushy interior, not a deep ocean
Reanalysis of Cassini data suggests Titan has a thick, slushy layer with tunnels and pockets of meltwater near a rocky core rather than a single deep ocean. The result could change ideas about habitability and will be testable by the Dragonfly mission.
New images reveal complex nova eruptions
Astronomers used interferometry at the CHARA Array to take direct images of two novae soon after they erupted. The pictures show multiple outflows and, in one case, a delayed release of material.