An artistic depiction imagines a dense dust structure surrounding supermassive black holes and their accretion disks. A study by researchers at Durham University utilizing the ALMA observatory has unveiled that quasars can be masked by the heavy gas and dust within starburst galaxies, challenging the previously held notion that such obscuration was solely due to nearby dust formations. Credit: ESA / V. Beckmann (NASA-GSFC)
Recent investigations have uncovered that the luminous cores of galaxies, quasars, can be concealed by the galaxies that contain them. This finding is at odds with the former assumption that quasar luminosity is only reduced by neighboring dust structures, offering new perspectives on galactic evolution and their central black holes.
Research findings now indicate that the supermassive black holes at the heart of galaxies, also known as quasars, may be hidden by thick interstellar gas and dust within the galaxy itself.
This discovery questions the conventional belief that quasars are only masked by dust in the shape of a torus close to the black hole.
Recent Scientific Insights
Quasars, the extraordinarily bright celestial bodies powered by material-consuming black holes, may have their intense light blocked by dense interstellar clouds.
Astronomers previously believed that this blocking material was limited to the immediate environment of the quasar, within a “dusty torus” that surrounds the black hole.
However, a research team from Durham University has presented evidence that in certain quasars, the host galaxy is entirely responsible for the obscuration.
Visual interpretation shows the locations of obscuration: orange depicts the dust and gas near the central black hole, and blue indicates the star-forming dust and gas within the galaxy. The blue color’s gradient illustrates the gas and dust density in the galaxy, ranging from sparse (transparent) to dense (opaque). Credit: Durham University
Employing the Atacama Large Millimeter Array (ALMA) in Chile, the team studied a group of quasars deeply enshrouded in dust with high star formation rates. Their findings show that many of these quasars are situated in compact starburst galaxies, with a span not exceeding 3000 light-years.
Starburst galaxies are capable of producing over a thousand solar-like stars annually. To support this star-creation rate, an immense quantity of gas and dust is required—these being the fundamental components for star formation.
Within such galaxies, the upheaval of gas and dust caused by rapid star formation may accumulate and entirely obscure the quasar from view.
Consequences of the Discovery
The comprehensive study has been published in the journal Monthly Notices of the Royal Astronomical Society: Letters.
Carolina Andonie, a PhD student at Durham University’s Centre for Extragalactic Astronomy and lead author of the study, explained: “The quasar appears to be enshrouded within its host galaxy.”
“In certain scenarios, the galaxy is so densely packed with gas and dust that not even X-ray light can penetrate.
“We once thought the dusty donut encircling the black hole was the sole screen concealing the quasar. We now recognize the galaxy itself can contribute to this concealment.
“This seems to occur particularly during a quasar’s intense developmental phase.”
According to the research team, around 10-30% of quasars with rapid star formation are completely hidden by their host galaxies.
This discovery sheds light on the relationship between the development of galaxies and the activity of their central black holes.
Hidden quasars might represent a young stage in the evolutionary timeline, when emerging galaxies are teeming with cool gas and dust, stimulating swift star production and black hole expansion.
Professor David Alexander of Durham University, a co-author of the study, noted: “This is a chaotic and cluttered stage of evolution, characterized by collisions and clustering of gas and stars at the galactic core.
“This cosmic turmoil effectively enshrouds the nascent quasar within a birth cocoon of dust.”
Revealing these concealed quasars will aid researchers in understanding the intricate relationship between galaxies and the supermassive black holes that lie at their cores.
Reference: “Obscuration beyond the nucleus: infrared quasars can be buried in extreme compact starbursts” by Carolina Andonie, et al., 6 October 2023, Monthly Notices of the Royal Astronomical Society: Letters.
DOI: 10.1093/mnrasl/slad144
Frequently Asked Questions (FAQs) about quasar obscuration
Can galaxies hide their own central quasars?
Yes, new research has found that starburst galaxies, with their dense clouds of gas and dust, can obscure the quasars at their centers, challenging previous beliefs that only nearby dust rings could do so.
What has the recent study on quasars revealed about galaxy evolution?
The study reveals that dense interstellar material within starburst galaxies can hide quasars, suggesting that obscured quasars may be an early stage in galaxy evolution, characterized by intense star formation and black hole growth.
How do starburst galaxies contribute to quasar obscuration?
Starburst galaxies, which are compact and have high rates of star formation, produce vast amounts of gas and dust that can accumulate and completely hide the quasar, previously thought to be only obscured by the dusty torus around the black hole.
What new insights does this discovery provide on black holes?
The discovery that entire galaxies can obscure quasars provides new insights into the connection between galaxy growth and the activity of supermassive black holes at their centers.
Where can I find the full study on quasar obscuration by starburst galaxies?
The full study can be found in the journal Monthly Notices of the Royal Astronomical Society: Letters, with the detailed findings on how extreme compact starbursts can bury quasars.
More about quasar obscuration
- Durham University’s Centre for Extragalactic Astronomy
- Atacama Large Millimeter/submillimeter Array (ALMA)
- Monthly Notices of the Royal Astronomical Society: Letters
- European Space Agency (ESA) – Space Telescope
- NASA’s Goddard Space Flight Center (GSFC)
5 comments
wow just read about how starburst galaxies can actually hide quasars mind-blowing stuff science never ceases to amaze me.
gotta say the universe is full of surprises, hiding quasars in plain sight who would’ve guessed?
This stuff about quasars is fascinating but man, the articles got some heavy jargon makes it kinda hard to follow don’t ya think.
Heard about the new findings from Durham Uni sounds like a big deal in the astronomy world quasars and black holes are always so intriguing.
didn’t knew galaxies could be so dusty and messy, makes you wonder what else is out there hidden away from our eyes.