An Ancestor of Supermassive Black Holes, Found at Cosmic Dawn

Supermassive black holes are the most powerful and energetic phenomena in the Universe. The SMBH is located at the center of the Milky Way. The presence of black holes causes the nucleus of the galaxies to become more energetic than the other stars in the disk.

Astronomers have sought to learn more about the role of SMBHs in the evolution of the universe. The question of how early SMBHs formed in the Universe would place constraints on how they have influenced the universe over time. An international team observed the ancestors of an SMBH for the first time. This black hole existed far earlier than expected.

The team was led by a student and a professor from the University of Copenhagen. They were joined by researchers from the Technical University of Denmark, the Max Planck Institute for Astronomy, the European Southern Observatory, and the Institute de Radio Astronomie.

The data from the NASA/ESA Hubble Space Telescope was used to discover GNz7q. The object had properties that were similar to those of a quasar and a galaxy. They concluded that the object was the predecessor of an SMBH that existed over 13 billion years ago. The first galaxies in the Universe formed during this period.

This is the first time that any such object has been observed, despite previous simulations that indicated such objects existed. A recent UCPH press release states that Fujimoto is a postdoctoral fellow at the Niels Bohr Institute.

“The discovered object connects two rare populations of celestial objects, namely dusty starbursts and luminous quasars, and thereby provides a new avenue toward understanding the rapid growth of supermassive black holes in the early universe.”

The Hubble GOODS North field survey, one of the largest panoramic views of the early Universe in the ultraviolet spectrum, discovered this potential descendant of an SMBH. Approximately 15,000 galaxies were featured in the survey and 12,000 of them had high rates of star formation. One of these was GNz7q, which was visible as a red point source thanks to Hubble.

It is extremely faint in terms of X-rays, indicating a unique ultraviolet compact star-forming region or a black-hole accretion disk. The team concluded that the observed properties were consistent with the predictions made in the simulations. It suggests that GNz7q is related to quasars.

GNz7q was found at the center of the Hubble GOODS-N, which is one of the most intensely-studied survey fields. The team was only able to notice it because of the survey's richly-detailed multi-wavelength datasets. Without these, the object would not have been noticed since it lacks the distinguishing features of quasars.

This shows how big discoveries can be hidden right in front of you. It's not likely that discovering GNz7q within the relatively small GOODS-N survey was just dumb luck, but rather that the prevalence of such sources may be significantly higher than previously thought.

The type of quasars linked to the discovery have very high rates of star formation and dust at the center. Older quasars, such as those observed closer to the Milky Way, have a much higher brightness because of their SMBHs causing a lot of gas to fall into the atmosphere at a fraction of the speed of light. As the gas infalls towards the black hole's outer edge, it heats up due to intense friction and releases tremendous amounts of energy as light and heat.

Young galaxies with high rates of star formation cause them to release heat and dust. The quasar glows brightly in the IR spectrum because of the dust absorbing light from around the SMBH. The rate of new stars forming is 1,600 times greater in the case of GNz7q than in the case of the Milky Way. As the explanation was given by Brammer.

“Understanding how supermassive black holes form and grow in the early universe has become a major mystery. Theorists have predicted that these black holes undergo an early phase of rapid growth: a dust-reddened compact object emerges from a heavily dust-obscured starburst galaxy, then transitions to an unobscured luminous compact object by expelling the surrounding gas and dust.”

“Although luminous quasars had already been found even at the earliest epochs of the universe, the transition phase of rapid growth of both the black hole and its star-bursting host had not been found at similar epochs. Moreover, the observed properties are in excellent agreement with the theoretical simulations and suggest that GNz7q is the first example of the transitioning, rapid growth phase of black holes at the dusty star core, an ancestor of the later supermassive black hole.”

The team hopes to use the James Webb Space Telescope to find similar objects. The James Webb will be able to see the earliest galaxies when they were still forming, thanks to its suite of cameras and spectrometers. Astronomers will be able to see how the Universe has evolved over time. Fujimoto summarized:

With the James Webb Telescope, it will be possible to fully investigate the evolution and underlying physics of these objects. The power to determine how common these rapidly growing black holes are will be taken care of once in regular operation.

NASA's Nancy Grace Roman (RST) is one of the next-generation instruments that will be joined by the James Webb. The Thirty Meter Telescope, the Giant Magellan Telescope, and the Extremely Large Telescope will all become operational at the same time.

These observatories will look back at the beginning of the Universe, revealing new insights into Dark Matter, Dark Energy, and Cosmic evolution. Astronomers will finally be able to study the earliest periods of the Universe because of the Dark Ages.

The paper about their research and findings was published in the journal Nature. You can check out the animation of what it would be like to zoom in on GNz7q.

Further reading: UCPH.