An article published in “The Astrophysical Journal Letters” reports the results of a census of the youngest supermassive black holes that existed in the early universe. A team of researchers used observations conducted with the Hubble Space Telescope that started from the so-called Hubble Ultra Deep Field to search for primordial supermassive black holes with the addition of data recently collected using the James Webb Space Telescope. The conclusion is that these objects are more numerous than expected, a confirmation that they formed very quickly. This new study will help to understand how.
The image (NASA, ESA, M. Hayes (Stockholm University), J. DePasquale (STScI)) shows the Hubble Ultra Deep Field with an inset that shows a magnification of two primordial galaxies, one of which contains a supermassive black hole that appears as a bright white spot thanks to its activity.
In 2004, the Hubble Ultra Deep Field image took the study of primordial galaxies to levels never reached before. It represented a new milestone in the study of galaxies that we see as they were in the early stages of their lives. From there, a new phase of studies began with observations and new developments in cosmological models connected to the formation and evolution of galaxies.
A phase of studies also began about the supermassive black holes that were found even at the center of primordial galaxies. Other instruments contributed to this type of study by confirming that supermassive black holes were common when the universe was very young. This posed the problem of understanding how they could have reached masses that were already many millions of times the Sun’s very quickly from an astronomical point of view.
This new census of the youngest supermassive black holes indicates that there were more of them than expected. Areas such as the Hubble Ultra Deep Field were imaged again, providing new details and detecting variations in the brightness of the galaxies photographed, a sign of the activity of supermassive black holes. That helped identify them with better results than other methods.
This new census suggests that some of those supermassive black holes may have formed from the collapse of some of the first stars that existed in the universe. According to the models, they could have been truly colossal stars devoid of elements heavier than hydrogen and helium, a situation only possible in the very early phase of the history of the universe, before stars generated heavier elements.
Each new study can offer new details and new results that are useful for better understanding the early phases of the history of the universe, in this case, the formation of the first supermassive black holes. Their evolution is linked to that of the galaxies that host them, so understanding the processes that led to the formation of supermassive black holes helps to understand the formation and evolution of galaxies.
This census offers new clues to test various cosmological models for the formation of supermassive black holes, including one that sees dark matter as a factor in the rapid growth of primordial supermassive black holes, recently published in the journal “Physical Review Letters”.
Observations with the James Webb Space Telescope are adding new details about primordial galaxies and their supermassive black holes. This also provides greater precision in estimating their masses, which is a great help in testing various models of their formation to solve a major mystery concerning the early history of the universe.
