active galactic nuclei Archives

August 27, 2023August 27, 2023 by Brian Koberlein

The Early Universe Should Be Awash in Active Galaxies, but JWST Isn't Finding Them

Artist view of an active black hole in the early universe. Credit: Boston University/Cosmovision

For decades the most distant objects we could see were quasars. We now know they are powerful active black holes. Active galactic nuclei so distant that they resemble star-like points of light. It tells us that supermassive black holes in the early Universe can be powerful monsters that drive the evolution of their galaxies. We had thought most early supermassive black holes went through such an active phase, but a new study suggests most supermassive black holes don’t.

May 23, 2023May 23, 2023 by Matt Williams

eROSITA Sees Changes in the Most Powerful Quasar

Artist’s impression of a quasar. These all have supermassive black holes at their hearts. Credit: NOIRLab/NSF/AURA/J. da Silva

After almost seventy years of study, astronomers are still fascinated by active galactic nuclei (AGN), otherwise known as quasi-stellar objects (or “quasars.”) These are the result of supermassive black holes (SMBHs) at the center of massive galaxies, which cause gas and dust to fall in around them and form accretion disks. The material in these disks is accelerated to close to the speed of light, causing it to release tremendous amounts of radiation in the visible, radio, infrared, ultraviolet, gamma-ray, and X-ray wavelengths. In fact, quasars are so bright that they temporarily outshine every star in their host galaxy’s disk combined.

The brightest quasar observed to date, 100,000 billion times as luminous as our Sun, is known as SMSS J114447.77-430859.3 (J1144). This AGN is hosted by a galaxy located roughly 9.6 billion light years from Earth between the constellations Centaurus and Hydra. Using data from the eROSITA All Sky Survey and other space telescopes, an international team of astronomers conducted the first X-ray observations of J1144. This data allowed the team to investigate prevailing theories about AGNs that could provide new insight into the inner workings of quasars and how they affect their host galaxies.

May 11, 2023May 11, 2023 by Evan Gough

Advanced Life Should Have Already Peaked Billions of Years Ago

The Drake Equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe. Credit: University of Rochester

Did humanity miss the party? Are SETI, the Drake Equation, and the Fermi Paradox all just artifacts of our ignorance about Advanced Life in the Universe? And if we are wrong, how would we know?

A new study focusing on black holes and their powerful effect on star formation suggests that we, as advanced life, might be relics from a bygone age in the Universe.

January 24, 2023January 24, 2023 by Matt Williams

Dust is Hiding how Powerful Quasars Really are

An artist’s impression of what the dust around a quasar might look like from a light year away. Credit Peter Z. Harrington

In the 1970s, astronomers discovered that the persistent radio source at the center of our galaxy was a supermassive black hole (SMBH). Today, this gravitational behemoth is known as Sagittarius A* and has a mass roughly 4 million times that of the Sun. Since then, surveys have shown that SMBHs reside at the center of most massive galaxies and play a vital role in star formation and galactic evolution. In addition, the way these black holes consume gas and dust causes their respective galaxies to emit a tremendous amount of radiation from their Galactic Centers.

These are what astronomers refer to as Active Galactic Nuclei (AGN), or quasars, which can become so bright that they temporarily outshine all the stars in their disks. In fact, AGNs are the most powerful compact steady sources of energy in the Universe, which is why astronomers are always trying to get a closer look at them. For instance, a new study led by the University of California, Santa Cruz (UCSC) indicates that scientists have substantially underestimated the amount of energy emitted by AGN by not recognizing the extent to which their light is dimmed by dust.

December 23, 2022December 23, 2022 by Evan Gough

Webb’s New Image Reveals a Galaxy Awash in Star Formation

This JWST image shows NGC 7469, a luminous, face-on spiral galaxy approximately 90 000 light-years in diameter that lies roughly 220 million light-years from Earth in the constellation Pegasus. Image Credit: ESA/Webb, NASA & CSA, L. Armus, A. S. Evans

When a spiral galaxy presents itself just right, observations reveal more detail. That’s the case with NGC 7469, a spiral galaxy about 220 million light-years away. It’s face-on towards us, and the James Webb Space Telescope captured its revealing scientific portrait.

November 4, 2022November 4, 2022 by Evan Gough

IceCube Senses Neutrinos Streaming From an Active Galaxy 47 Million Light-Years Away

This is a Hubble Space Telescope image of the Messier 77 spiral galaxy. Scientists working with the IceCube Neutrino Observatory detected neutrinos emanating from the galaxy's core. Image Credit: By NASA, ESA & A. van der Hoeven - http://www.spacetelescope.org/news/heic1305/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=25328266

Researchers using the IceCube Neutrino Observatory have detected neutrinos emanating from the energetic core of an active galaxy millions of light-years away. Neutrinos are difficult to detect, and finding them originating from the galaxy is a significant development. What does the discovery mean?

October 13, 2022October 13, 2022 by Evan Gough

Webb Sees Organic Molecules in the Hearts of Galaxies, Surprisingly Close to Active Supermassive Black Holes

Artist view of an active supermassive black hole. Credit: ESO/L. Calçada

When the James Webb Space Telescope (JWST) launched, one of its jobs was studying galactic formation and evolution. When we look around the Universe, today’s galaxies take the shape of grand spirals like the Whirlpool galaxy and giant ellipticals like M60. But galaxies didn’t always look like this.

We don’t see these shapes when we look at the most distant and most ancient galaxies. Early galaxies are lumpy and misshapen and lack the structure of modern galaxies.

A new study based on JSWT observations looks at organic molecules near galactic centers. The researchers say observing these molecules can teach us a lot about galactic evolution.

February 2, 2021February 1, 2021 by Paul M. Sutter

Astronomers are Starting to Understand the Quasar Lifecycle

Illustration of an active quasar. New research shows that SMBHs eat rapidly enough to trigger them. Credit: ESO/M. Kornmesser

Supermassive black holes have a complicated lifecycle. Sometimes they’re “on”, blasting out tremendous amounts of energy, and sometimes they’re “off’, where they sleep like dragons in their caves. By comparing the proportion of high-energy to low-energy waves emitted by quasars, astronomers are beginning to pin down how many black holes are sleeping, and when they’re likely to wake back up.

June 22, 2020June 22, 2020 by Evan Gough

Quasars are the Biggest Particle Accelerators in the Universe

Composite image of Centaurus A, showing the jets emerging from the galaxy’s central black hole, together with the associated gamma radiation. © ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray), H.E.S.S. collaboration (Gamma)

We puny humans think we can accelerate particles? Look how proud we are of the Large Hadron Collider. But any particle accelerator we build will pale in comparison to Quasars, nature’s champion accelerators.

Those things are beasts.

March 2, 2020March 2, 2020 by Evan Gough

Astronomers Have Recorded the Biggest Explosion Ever Seen in the Universe

Hundreds of millions of light years away, a supermassive black hole sits in the center of a galaxy cluster named Ophiuchus. Though black holes are renowned for sucking in surrounding material, they sometimes expel material in jets. This black hole is the site of an almost unimaginably powerful explosion, created when an enormous amount of material was expelled.