This black hole has one of the biggest and most impressive jets ever

By analyzing the light emitted from this galaxy using radio tools and telescopes, astronomers have discovered that NGC 2663 appears to be an elliptical galaxy, and it could host ten times more stars than our own spiral galaxy. For comparison, there could be between 100 and 400 billion stars in the Milky Way galaxy, so we’re looking at an enormous galaxy here. 

As part of the Evolutionary Map of the Universe (EMU) survey, this discovery was made using a network of around 35 interconnected radio dishes.

Engineering the square kilometer array pathfinder

The tool used in the research was the Commonwealth Scientific and Industrial Research Organisation's Australian Square Kilometer Array Pathfinder (CISRO ASKAP), which consists of 36 dish antennas that work together as one telescope. You might be wondering how 36 different radio dishes can work in tandem to produce an “image” of a galaxy almost 100 million light-years from Earth. Some may say it’s simple, but with most things, this technologically advanced (and ASKAP is one of the most powerful “survey radio astronomy instruments” in the sky), not exactly. 

Each dish is an antenna around 40 feet (12 meters) in diameter, standing three stories high and spread around 2.3 square miles (6 square km) of the Australian outback. Each is equipped with its own phased array feed receiver, which is placed at the highest point on every antenna and serves as the antenna’s “eyes.” Except these eyes are extremely powerful radio cameras, capable of observing the faint glow of photons millions of light years away at radio frequencies. This is different from some other radio telescopes, which generally detect these radio waves in single-pixel feeds. 

According to Australia's National Science Agency (ANSA), “ASKAP generates data at the rate of 100 trillion bits per second – more data at a faster rate than Australia’s entire internet traffic.”

“At the heart of ASKAP is the ‘correlator,’ a high-speed digital signal processing system that extracts astronomy signals from this massive amount of data. Using the Pawsey Supercomputing Research Centre and custom-written software, we produce science-ready datasets of many Terabytes for each observation, served to astronomers through ASKAP’s science archive.”

This technology has already gained a lot of ground. As ANSA further notes, “ASKAP broke records with the fastest survey of the southern sky ever completed. Documenting three million galaxies in only 300 hours, one million of those galaxies had never been seen before.” That was in a different study, called the Rapid ASKAP Continuum Survey, which was the very first large-scale deep dive ASKAP made of the skies. 

With this survey, the Evolutionary Map of the Universe (EMU) aims to study a large portion of the southern sky. In addition to the discovery we’re about to talk about, once complete, it’s expected to help us further our understanding of how the first stars and galaxies came into existence by studying galaxies in various stages of evolution. Some may have popped into existence in as little as half a billion years after the Big Bang. 

What was found

During the survey, which combined multi-wavelength data from the Murchison Widefield Array, ASKAP, the Australia Telescope Compact Array, and X-ray data from Chandra, Swift, and SRG/eROSITA, astronomers found that the radio frequencies of NGC 2663 revealed an astonishing supermassive black hole at the galaxy’s core. It emits extremely large and powerful radio jets. So powerful, in fact, it’s one of the biggest jet streams ever detected emitting from a black hole – traveling at nearly the speed of light and extending over 355 Kpc across the sky, which corresponds to approximately 1,150 light years. This makes NGC 2663 one of the nearby universe's largest radio galaxies (in projected angular size). It has been said that if we could see it with our own two eyes, it would be bigger than the moon (which is rather impressive, given it’s still 93 million light-years away from us).

The black hole in the galactic center of NGC 2663 is of note because its jets contain a phenomenon called “shock diamonds.” Simply put, this just means that the jets have spaced out regions that are bright and darker and appear to look like diamonds. They are called shock diamonds because they are created by the shock waves produced by the interaction between the interstellar medium and the jet, which travels at almost the speed of light, akin to what we see in the exhaust patterns of fighter jets. 

The research was led by Velibor Velovic, a doctoral student at Western Sydney University, and was published in the journal “Monthly Notices of the Royal Astronomical Society." The paper explains that astronomers have seen these patterns before but never on a scale as large as this. One explanation is that they are created through a process similar to that seen with fighter jets. It’s explained that, with fighter jets, ambient pressure pushes the exhaust plume from the sides as it glides through the atmosphere. In the context of black hole jets, the brightly lit ionized gases making up the jets expand and contract. When they compress and contract, the gases glow more brilliantly, and it appears as though the light is pulsating. 

Per The Conversation, “This tells us there is enough matter in the intergalactic space around NGC2663 to push against the sides of the jet. In turn, the jet heats and pressurizes the matter.”

“This is a feedback loop: intergalactic matter feeds into a galaxy, galaxy makes black hole, black hole launches jet, jet slows supply of intergalactic matter into galaxies.” 

This discovery could help researchers to better understand the intricacies of the relationship between galaxies and black hole jets and could ultimately provide information on how the jets impact the evolution of the universe. It’s expected that ASKAP will continue to make more groundbreaking discoveries as it continues to comb through the southern skies.

It may have already helped solve one mystery involving supernova remnants (SNRs) – giant clouds of dust and gas created by a star going supernova. However, based on the age and density of the Milky Way, we should see many more SNRs than have been discovered so far. So where are they?

Recent data from ASKAP and others indicates that the missing SNRs may, in fact, have been there all along – they are just invisible to most of our instruments.

However, recent images combining observations from ASKAP and the Parkes radio telescope have highlighted up to twenty SNRs in the galactic plane.

Both telescopes are also being used for long-term projects that will map out much of the Milky Way, which researchers hope will reveal as many as 1,500 new supernova remnants.

And that is likely just the beginning.