Astronomers discover rapidly expanding black holes in extreme galaxies in the very early universe

Cultivating Black Hole Quasar

Artist’s concept of a growing black hole seen at the center of a distant galaxy. Credit: NASA/JPL-Caltech

New discovery sheds light on very early supermassive black holes

Astronomers from the University of Texas and the University of Arizona have discovered a rapidly expanding black hole in one of the most extreme galaxies known in the early universe. The discovery of the galaxy and

The black hole is considered to be a new type of primordial black hole – one that is heavily shrouded in cosmic “dust”, which causes almost all of its light to be emitted in the mid-infrared region of the electromagnetic spectrum. The researchers also found that this growing supermassive black hole (often referred to as an active galactic nucleus) generates a strong jet of material that moves at near the speed of light through its host galaxy.

Today, black holes with masses millions to billions of times larger than our own Sun sit at the center of almost every galaxy. How these supermassive black holes first formed remains a mystery to scientists, especially because several of these objects were found when the universe was very young. Because the light from these sources takes so long to reach us, we see them as they existed in the past; in this case, just 750 million years after

IC 694 and NGC 3690

This system consists of a pair of galaxies, called IC 694 and NGC 3690, which made a close pass about 700 million years ago. As a result of this interaction, the system underwent a violent burst of star formation. In the past fifteen years or so, six supernovae have appeared in the outer reaches of the galaxy, making this system a prominent supernova factory. Credit: NASA, ESA, Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)

The only other class of supermassive black holes we knew about in the very early universe are quasars, which are active black holes that are relatively unobscured by cosmic dust. These quasars are extremely rare at distances similar to COS-87259, with only a few tens located across the sky. The surprising discovery of COS-87259 and its black hole raises several questions about the abundance of very early supermassive black holes, as well as the types of galaxies in which they typically form.

Ryan Endsley, lead author of the paper and now a postdoctoral researcher at the University of Texas at Austin, says: “These results suggest that very early supermassive black holes were often heavily obscured by dust, perhaps as a consequence of the intense star formation activity in their host galaxies. This is something others have been predicting for a few years now, and it’s very nice to see the first direct observational evidence supporting this scenario.”

Similar types of objects have been found in the more local, present-day universe, such as Arp 299 shown above. In this system, two galaxies collide, generating an intense starburst as well as powerful obscuration by the growing supermassive black hole in one of the two galaxies.

Endsley adds, “While no one expected to find this type of object in the very early universe, the discovery takes a step toward building a much better understanding of how billions of solar mass black holes were able to form so early in the universe’s lifetime, as well how the most massive galaxies first evolved.”

Reference: “ALMA confirmation of a hidden hyperluminous radio-loud AGN at z = 6,853 associated with a dusty starburst in the 1.5 degrees 2 COSMOS field” by Ryan Endsley, Daniel P Stark, Jianwei Lyu, Feige Wang, Jinyi Yang, Xiaohui Fan, Renske Smit, Rychard Bouwens, Kevin Hainline and Sander Schouws, 24 February 2023, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stad266

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