Astronomers have confirmed the existence of the earliest and most distant black hole ever observed, located in the galaxy known as CAPERS-LRD-z9. This remarkable discovery reveals that the black hole, which is approximately 300 million times the mass of the Sun, existed just 500 million years after the Big Bang. At this stage, the Universe was only about 3 percent of its current age, challenging previous understandings of cosmic evolution.
This finding also offers insights into a previously enigmatic group of celestial objects referred to as Little Red Dots (LRDs). These small, bright, red objects emerged around 600 million years post-Big Bang and began to disappear less than a billion years later. The James Webb Space Telescope (JWST) has played a crucial role in unveiling these phenomena, utilizing its advanced infrared capabilities to explore the early epochs of the Universe, notably during the Cosmic Dawn.
Insights from CAPERS-LRD-z9’s Supermassive Black Hole
The newly confirmed black hole at the core of CAPERS-LRD-z9 is classified as an active galactic nucleus (AGN), which indicates it is a bright, rapidly feeding black hole. Its distinctive red appearance is attributed to a surrounding cocoon of gas and dust. This supermassive black hole generates powerful winds, propelling gas at speeds of approximately 3,000 kilometers (or 1,864 miles) per second—about 1 percent of the speed of light. Such extreme conditions allow astronomers to identify the presence of black holes through a technique known as spectroscopy.
Lead author Anthony Taylor, an astrophysicist at the University of Texas at Austin, emphasizes the rarity of such spectral signatures, stating, “There aren’t many other things that create this signature.” Spectroscopy works by splitting light into its component wavelengths, providing valuable information about celestial objects. For instance, light emitted from gas retreating from an observer undergoes a redshift, while light moving towards an observer experiences a blueshift. These shifts enable scientists to deduce the velocity of objects in space.
The confirmation of CAPERS-LRD-z9 supports the hypothesis that LRDs may harbor supermassive black holes, with some potentially reaching upwards of 10 million solar masses within their first billion years. In comparison, the supermassive black hole at the center of the Milky Way is approximately 4 million solar masses. The black hole in CAPERS-LRD-z9 is particularly notable for its mass ratio, which may approach 10 to 100 percent of its host galaxy’s stellar mass. At around 300 million solar masses, it represents about half the mass of all the stars in its galaxy, whereas black holes in more local galaxies typically account for only about 0.1 percent of their stellar mass.
Theories on Black Hole Formation and Cosmic Evolution
Researchers believe there are two primary pathways for a black hole to attain such immense mass within a mere 500 million years of cosmic history. Both scenarios start with a significant “seed” black hole. If it grows at the theoretical maximum known as the Eddington rate, it may have initially possessed around 10,000 solar masses. Alternatively, a smaller seed black hole, beginning with just 100 solar masses, could achieve rapid growth at the super-Eddington rate, drawing in gas from its dense surroundings.
The origins of these seed black holes may trace back to primordial black holes created during the Big Bang, or they could result from the collapse of Population III stars, the first stars to illuminate the cosmos. Other possibilities include “runaway collisions” in dense star clusters or the direct collapse of massive primordial gas clouds.
The significance of this research extends beyond the discovery of a black hole; it adds to the understanding of LRDs as a transient phenomenon in the early Universe, potentially marking an initial phase in galactic evolution that may have contributed to the formation of the Milky Way itself.
This groundbreaking study has been published in the Astrophysical Journal Letters, underscoring the ongoing efforts to push the boundaries of astronomical discovery. Taylor notes, “When looking for black holes, this is about as far back as you can practically go. We’re really pushing the boundaries of what current technology can detect.”
