Understanding how supermassive black holes form and grow in the early universe has become a major challenge. Astronomers now believe they have discovered a critical “lost link” in space since the beginning of the Universe.
Using data from NASA’s Hubble Space Telescope, astronomers identified a fast-growing black hole in the early universe. This black hole, called GNz7q, is considered the missing link between young star-forming galaxies and the first supermassive black holes.
It existed only 750 million years after the big bang, the GNz7q is a newly formed black hole. Hubble detected a compact source of ultraviolet (UV) and infrared light consistent with the expected radiation from materials falling on a black hole.
Only computer theories and simulations have predicted fast-growing black holes in dusty, early star-forming galaxies. But so far they have not been observed.
Seiji Fujimoto, an astronomer at the Niels Bohr Institute at the University of Copenhagen, said: “Our analysis suggests that GNz7q is the first example of a fast-growing black hole in the dusty core of a starburst galaxy. lar in a time close to the oldest supermassive. black hole known in the universe “.
“The properties of the object across the electromagnetic spectrum are in excellent agreement with the predictions of theoretical simulations.”
How did supermassive black holes, with millions or billions of times the mass of the Sun, get so big so fast? This remains the greatest mystery of astronomy.
Current theories suggest that supermassive black holes begin their life in the dust-filled nuclei of stellar galaxies that form vigorously before expelling the surrounding gas and dust and emerging as extremely bright quasars. Although rare, both starburst galaxies and extremely bright quasars have been detected in the early universe.
According to scientists, GNz7q could be a missing link between these two classes of objects. GNz7q has exactly the two aspects of the dust of the starry galaxy and the quasar, where the light from the quasar shows the reddish color of the dust. In addition, the GNz7q does not have several characteristics that are commonly observed in typical and very bright quasars (corresponding to the emission of the accretion disk of the supermassive black hole), which probably explains why the central black hole of the GN7q it is still in a young and less massive environment. phase.
These properties coincide perfectly with the young transition phase quasar predicted in the simulations, but never identified in the Universe with a high redshift as the very bright quasars identified so far up to a redshift of 7.6 .
Fujimoto said: “GNz7q provides a direct connection between these two rare populations and provides a new way to understand the rapid growth of supermassive black holes in the early days of the universe. Our discovery provides an example of precursors to supermassive black holes that we observe in later times “.
Although alternative interpretations of the computer data cannot be completely ruled out, the observed characteristics of GNz7q are very similar to the theoretical predictions. The host galaxy of GNz7q produces stars at a speed of 1,600 solar masses per year, and GNz7q itself is bright in UV but faint in X-ray wavelengths.
The accretion disk of a massive black hole should be very bright in UV and X-ray light. However, while Hubble identified UV light this time, even one of the X-ray data sets Deepest light could not identify the X-ray light. These findings indicate that the center of the accretion disk, where the X-rays originate, is still veiled, while the outer section, where the UV light is created, is ‘is discovering. According to this theory, GNz7q is a rapidly expanding black hole hidden by the dusty core of its star-forming host galaxy.
Gabriel Brammer, another astronomer at the Niels Bohr Institute at the University of Copenhagen and a member of the team behind this result, said: “GNz7q is a unique discovery that was found right in the center of a well-studied famous celestial field … proves that great discoveries can often be hidden right in front of you – discovering GNz7q in the relatively small area of the GOODS-North survey was just “silly luck” , but the prevalence of these sources may be significantly higher than previously thought. “
Finding GNz7q hidden from view was only possible thanks to the unique multi-wavelength and detailed datasets available for GOODS-North. Without this wealth of data, GNz7q would have been easy to overlook, as it lacks the distinctive features commonly used to identify quasars in the early universe. The team now hopes to search for similar objects through dedicated high-resolution surveys in a systematic way and take advantage of the spectroscopic instruments of NASA’s James Webb Space Telescope to study objects like GNz7q in unprecedented detail.
Magazine reference:
- Fujimoto, S., Brammer, GB, Watson, D. et al. A dusty compact object linking galaxies and quasars to cosmic dawn. Nature 604, 261–265 (2022). DOI: 10.1038 / s41586-022-04454-1