quasar Archives

January 14, 2025January 14, 2025 by Mark Thompson

This Quasar Helped End the Dark Ages of the Universe

(AI-generated image created with researcher illustration, edited by Michael S. Helfenbein)

After the Big Bang came the Dark Ages, a period lasting hundreds of millions of years when the universe was largely without light. It ended in the epoch of reionization when neutral hydrogen atoms became charged for the first time and the first generation of stars started to form. The question that has perplexed astronomers is what caused the first hydrogen atoms to charge. A team of researchers have observed an early quasar that pumped out enormous amounts of x-ray radiation helping to drive the reionization.

November 14, 2024November 14, 2024 by Mark Thompson

Why are Some Quasars So Lonely?

This image, taken by NASA’s James Webb Space Telescope, shows an ancient quasar (circled in red) with fewer than expected neighboring galaxies (bright spheres), challenging physicists’ understanding of how the first quasars and supermassive black holes formed. Credits:Credit: Christina Eilers/EIGER team

At the centre of most galaxies are supermassive black holes. When they are ‘feeding’ they blast out jets of material with associated radiation that can outshine the rest of the galaxy. These are known as quasars and they are usually found in regions where huge quantities of gas exist. However, a recent study found a higher than expected number of quasars that are alone in the Universe. These loners are not surrounded by galaxies nor a supply of gas. The question therefore remains, how are they shining so brightly.

May 29, 2024May 29, 2024 by Mark Thompson

There’s Another, More Boring Explanation for those Dyson Sphere Candidate Stars

Dyson Spheres have been a tantalising digression in the hunt for alien intelligence. Just recently seven stars have been identified as potential candidates with most of their radiation given off in the infrared wavelengths. Potentially this is the signature of heat from a matrix of spacecraft around the star but alas, a new paper has another slightly less exciting explanation; dust obscured galaxies.

February 19, 2024February 19, 2024 by Mark Thompson

What are the Differences Between Quasars and Microquasars?

Quasars are fascinating objects; supermassive black holes that are actively feasting on material from their accretion disks. The result is a jet that can outshine the combined light from the entire galaxy! There are smaller blackholes too that are the result of the death of stars and these also sometimes seem to host accretion disks and jets just like their larger cousins. We call these microquasars and, whilst there are similarities between them, there are differences too.

February 2, 2024February 2, 2024 by Matt Williams

Astronomers are Getting Really Good at Weighing Baby Supermassive Black Holes

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

In the 1970s, astronomers deduced that the persistent radio source coming from the center of our galaxy was actually a supermassive black hole (SMBH). This black hole, known today as Sagittarius A*, is over 4 million solar masses and is detectable by the radiation it emits in multiple wavelengths. Since then, astronomers have found that SMBHs reside at the center of most massive galaxies, some of which are far more massive than our own! Over time, astronomers observed relationships between the properties of galaxies and the mass of their SMBHs, suggesting that the two co-evolve.

Using the GRAVITY+ instrument at the Very Large Telescope Interferometer (VLTI), a team from the Max Planck Institute for Extraterrestrial Physics (MPE) recently measured the mass of an SMBH in SDSS J092034.17+065718.0. At a distance of about 11 billion light-years from our Solar System, this galaxy existed when the Universe was just two billion years old. To their surprise, they found that the SMBH weighs in at a modest 320 million solar masses, which is significantly under-massive compared to the mass of its host galaxy. These findings could revolutionize our understanding of the relationship between galaxies and the black holes residing at their centers.

January 24, 2024January 24, 2024 by Brian Koberlein

Webb Sees Dozens Of Young Quasars in the First Billion Years of the Universe

Artist's impression of blue quasar in the early universe. Credit: S. Munro / CC BY 4.0

Within almost every galaxy is a supermassive black hole. Millions, sometimes billions of solar masses locked within an event horizon of space and time. They can power luminous quasars, drive star formation, and change the evolution of a galaxy. Because of their size and abundance, supermassive black holes must have formed early in cosmic history. But how early is still an unanswered question. It’s a focus of a recent study on the arXiv.

September 22, 2021September 22, 2021 by David Dickinson

Using Quasars as a New Standard Candle to Define Distance

A new study shows a way to use quasars to gauge distance in the early Universe.

The simple question of ‘how far?’ gets at the heart of the history of modern astronomy. Looking out across our galactic backyard into the primordial Universe, different yardsticks—often referred to as ‘standard candles’ —are used to gauge various distances, from near to far.

December 15, 2020December 15, 2020 by Matthew Cimone

A Galaxy is Making New Stars Faster Than its Black Hole Can Starve Them for Fuel

Computer Simulation of a Quasar, a Supermassive Black Hole that is actively feeding and creating tremendous energy - created in "SpaceEngine" pro by author

A monster lurks at the heart of many galaxies – even our own Milky Way. This monster possesses the mass of millions or billions of Suns. Immense gravity shrouds it within a dark cocoon of space and time – a supermassive black hole. But while hidden in darkness and difficult to observe, black holes can also shine brighter than an entire galaxy. When feeding, these sleeping monsters awaken transforming into a quasar – one of the Universe’s most luminous objects. The energy a quasar radiates into space is so powerful, it can interfere with star formation for thousands of light years across their host galaxies. But one galaxy appears to be winning a struggle against its awoken blazing monster and in a recent paper published in the Astrophysical Journal, astronomers are trying to determine how this galaxy survives.

Animation of Interstellar Matter Falling into a Black Hole Creating a Quasar – ESA

July 31, 2020July 30, 2020 by Paul M. Sutter

Supermassive black holes can cloak themselves in a cocoon of dust, making them invisible even when they should be bright quasars

Artist's impression of a shroud of dust cloaking a supermassive black hole, alongside the X-ray view of where black holes should be. Image credit: X-ray: NASA/CXC/Penn State/B.Luo et al; Illustration: NASA/CXC/M. Weiss

Quasars are the most powerful sources of light in the universe, but sometimes they’re hard to find. A team of astronomers used the Chandra X-ray Space Telescope to find some diamonds in the rough.

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.