Ancient galaxy Reveals Surprisingly Massive Black Hole, Challenging Early Universe Theories
AUSTIN, TX – August 6, 2024 – Astronomers have confirmed the existence of a supermassive black hole within CAPERS-LRD-z9, a newly discovered galaxy dating back to the first 1.5 billion years of the universe. The black hole, estimated to be up to 300 million times the mass of our sun, is unusually large for its age and is prompting scientists to re-evaluate models of black hole and galaxy formation in the early cosmos. The discovery,made possible by the James Webb Space Telescope (JWST),was announced today by researchers at the University of Texas at Austin.
This finding marks a important step forward in understanding the “Little Red Dots” – a class of compact, red, and unexpectedly shining galaxies first identified through early JWST data. These galaxies, unlike anything previously observed with the Hubble Space Telescope, represent a puzzle for astronomers seeking to understand the universe’s formative years.
The team, led by researchers from the CAPERS (Cosmic Assembly Near-infrared Deep Extragalactic Survey) program, initially identified CAPERS-LRD-z9 as an intriguing point of light. Subsequent spectroscopic analysis with JWST confirmed its extreme distance and revealed key characteristics. “JWST spectroscopy is the key to confirming their distances and understanding their physical properties,” explains Mark Dickinson,a co-author on the study and CAPERS team lead.
The brightness of Little Red Dots initially suggested a high rate of star formation. However, the early age of these galaxies makes such a large stellar population improbable. The new data from CAPERS-LRD-z9 strongly supports the theory that supermassive black holes are the primary source of this luminosity. Black holes generate intense light and energy by compressing and heating matter as it falls into them.
Moreover, the galaxy’s distinct red color might potentially be caused by a dense cloud of gas surrounding the black hole, shifting the light towards longer, redder wavelengths. Researchers have observed similar gas clouds in other galaxies, and the characteristics of the cloud in CAPERS-LRD-z9 align with those previous observations.
What makes CAPERS-LRD-z9 especially noteworthy is the sheer size of its black hole – roughly half the mass of all the stars within the galaxy. This is exceptionally large, even for supermassive black holes. The early presence of such a massive black hole challenges existing theories about how these objects grow.
“This adds to growing evidence that early black holes grew much faster than we thought possible,” says Steve Finkelstein, a researcher involved in the study. “Or they started out far more massive than our models predict.”
Black holes in the later universe have had billions of years to accumulate mass through mergers and accretion. A black hole existing in the early universe,however,would have had limited time to grow,suggesting either a faster growth rate or a larger initial mass than previously assumed.The team plans to continue studying CAPERS-LRD-z9 with further, higher-resolution observations from JWST. These observations will aim to provide a more detailed understanding of the galaxy and the role black holes played in the growth of the earliest galaxies. Data from the Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory also contributed to the research.
“This is a good test object for us,” says researcher Taylor. “We haven’t been able to study early black hole evolution until recently,and we are excited to see what we can learn from this unique object.”
Source: UT Austin
