Currently, scientists do not have a complete picture of the formation of the first black holes. Supermassive black holes, at the center of galaxies, are believed to exist less than a billion years after the Big Bang.
Most of these objects appear more massive than expected at such early times. Either they formed very massively, or they grew exceptionally quickly.
An international team of scientists led by scientists in the Department of Astronomy at Stockholm University used NASA’s Hubble Space Telescope to determine how many black holes exist among a population of faint galaxies when the universe was just a few percent of its current age.
They found more black holes in the early universe than previously reported.
Hubble re-photographed the survey region for the observations. Based on observational data, scientists measured variations in the brightness of galaxies, which are signs of black holes.
To their surprise, there were more black holes than previously found by other methods. Some of these black holes formed after massive, pristine stars collapsed during the first billion years of cosmic time. Such stars can only exist at very early times in the universe because later-generation stars are polluted by the remnants of stars that have already lived and died.
Other factors in black hole formation include collapsing gas clouds, mergers of stars in massive clusters, and “primordial” black holes that formed in the first few seconds after the Big Bang.
This new information about black hole formation can lead to the development of more accurate models of galaxy formation.
Matthew Hayes from the Department of Astronomy at Stockholm University, the lead author of the study, said, “The formation mechanism of early black holes is an important part of the puzzle of galaxy evolution. Together with models for how black holes grow, galaxy evolution calculations can now be placed on a more physically motivated footing, with an accurate scheme for how black holes came into existence from collapsing massive stars.”
Journal Reference:
- Matthew J. Hayes, Jonathan C. Tan et al. Glimmers in the Cosmic Dawn: A Census of the Youngest Supermassive Black Holes by Photometric Variability*. The Astrophysical Journal Letters. DOI: 10.3847/2041-8213/ad63a7