galaxies Archives

June 21, 2021June 21, 2021 by Brian Koberlein

Supermassive Black Hole Winds Were Already Blowing Less Than a Billion Years After the Big Bang

Artist’s impression of a galactic wind driven by a supermassive black hole located in the center of a galaxy. Credit: ALMA (ESO/NAOJ/NRAO)

At the heart of most galaxies is a supermassive black hole. These beasts of gravity can play a crucial role in the formation and evolution of their galaxy. But astronomers still don’t fully understand when the influence of black holes becomes significant. Did large black holes form early in the universe, causing galaxies to form around them? Or did black holes grow after its primordial galaxy had begun to form? You might call this the chicken or egg problem. But a recent study suggests that galaxies and their supermassive black holes can have a mutual interaction that allows them to co-evolve.

June 15, 2021June 15, 2021 by Andy Tomaswick

Rare Triple Galaxy Merger With at Least Two Supermassive Black Holes

One of the best things about that universe is that there is so much to it. If you look hard enough, you can most likely find any combination of astronomical events happening. Not long ago we reported on research that found 7 separate instances of three galaxies colliding with one another. Now, a team led by Jonathan Williams of the University of Maryland has found another triple galaxy merging cluster, but this one might potentially have two active supermassive black holes, allowing astronomers to peer into the system dynamics of two of the universe’s most extreme objects running into one another.

February 22, 2021February 22, 2021 by Andy Tomaswick

Protogalaxy Cluster Found When the Cosmic Fog Was Starting to Clear, When the Universe Was Just 750 Million Years Old

Origin stories are a focus of many astronomical studies. Planetary formation, solar system formation, and even galaxy formation have long been studied in order to understand how the universe came to be where it is today. Now, a team of scientists from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) consortium have found an extremely early “protogalaxy” that was formed approximately 750 million years after the big bang. Studying it can provide insights into that early type of galaxy formation and everything that comes after.

February 5, 2021February 5, 2021 by Evan Gough

Astronomers Can Predict When a Galaxy’s Star Formation Ends Based on the Shape and Size of its Disk

An ensemble of twenty-five disk galaxies. The view on the left shows light emitted in the H-alpha line from interstellar gas as a result of ongoing star-formation, while the panels on the right shows the optical light emitted by a mix of young (bluer) and old (redder) stars. Each galaxy can be seen rotated edge-on below its face-on view. Image Credit: TNG Collaboration

A galaxy’s main business is star formation. And when they’re young, like youth everywhere, they keep themselves busy with it. But galaxies age, evolve, and experience a slow-down in their rate of star formation. Eventually, galaxies cease forming new stars altogether, and astronomers call that quenching. They’ve been studying quenching for decades, yet much about it remains a mystery.

A new study based on the IllustrisTNG simulations has found a link between a galaxy’s quenching and its stellar size.

February 2, 2021February 2, 2021 by Evan Gough

When Galaxies Collide, Black Holes Don’t Always Get the Feast They Were Hoping for

What happens when galaxies collide? Well, if any humans are around in about a billion years, they might find out. That’s when our Milky Way galaxy is scheduled to collide with our neighbour the Andromeda galaxy. That event will be an epic, titanic, collision. The supermassive black holes at the center of both galaxies will feast on new material and flare brightly as the collision brings more gas and dust within reach of their overwhelming gravitational pull. Where massive giant stars collide with each other, lighting up the skies and spraying deadly radiation everywhere. Right?

Maybe not. In fact, there might be no feasting at all, and hardly anything titanic about it.

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

Galaxy Mergers can Boost Star Formation, and it can Also Shut it Down

It is known today that merging galaxies play a large role in the evolution of galaxies and the formation of elliptical galaxies in particular. However there are only a few merging systems close enough to be observed in depth. The pair of interacting galaxies picture seen here — known as NGC 3921 — is one of these systems. NGC 3921 — found in the constellation of Ursa Major (The Great Bear) — is an interacting pair of disc galaxies in the late stages of its merger. Observations show that both of the galaxies involved were about the same mass and collided about 700 million years ago. You can see clearly in this image the disturbed morphology, tails and loops characteristic of a post-merger. The clash of galaxies caused a rush of star formation and previous Hubble observations showed over 1000 bright, young star clusters bursting to life at the heart of the galaxy pair.

Galaxy mergers are beautiful sights, but ultimately deadly. In the midst of the collision, the combined galaxy will shine brighter than it ever has before. But that glory comes with a price: all those new stars use up all the available fuel, and star formation grinds to a halt.

January 25, 2021January 25, 2021 by Andy Tomaswick

An Active Galaxy That Erupts Predictably Every 114 Days Or So

Computers are known for their ability to spot patterns. It’s what they are good at, and over the last 50+ years they have continued to improve. But they only know how to spot patterns if they know where to look for them in data. So sometimes, it falls to a human to truly see a pattern that no one expected to be there.

That is exactly what happened in the case of the discovery of the most consistent active galaxy yet discovered. Anna Payne, a graduate student at the University of Hawai’i at Manoa, was looking into data collected by the All Sky Automated Survey for Supernovae (ASAS-SN), and notice a strange feature about one of its galaxies, known as ESO 253-3: it was getting significantly brighter every 114 days.

January 23, 2021January 23, 2021 by Matthew Cimone

The Universe in Formation. Hubble Sees 6 Examples of Merging Galaxies

Newly released collage of six galaxy mergers used in the HiPEEC survey. Top Row Left to Right: NGC 3256, 1614, 4195 Bottom Row Left To Right: NGC 3690, 6052, 34 - Credit ESA/Hubble/NASA

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10 billion years ago, galaxies of the Universe were ablaze with the light of newly forming stars. This epic phase of history is known as “Cosmic Noon” – the height of all star creation. Galaxies like our Milky Way aren’t creating stars at nearly the rates they were in the ancient past. However, there is a time when galaxies in the present can explode with star formation – when they collide with each other. This recently published collage of merging galaxies by the Hubble HiPEEC survey (Hubble imaging Probe of Extreme Environments and Clusters) highlights six of these collisions which help us understand star formation in the early Universe.

January 11, 2021January 11, 2021 by Paul M. Sutter

This is the Fireworks Galaxy. It’s had ten Supernovae in the Last Century Alone

NGC 6946, also known as the Fireworks Galaxy due to the stupendous number of active supernovae. Image credit: ESA/Hubble & NASA, A. Leroy, K.S. Long

Say hello to NGC 6946, otherwise known as the Fireworks Galaxy. This little galaxy is the most prolific producer of supernovae in the known universe, popping off those incredible explosions roughly once a decade. It’s secret? An incredibly high rate of star formation.

December 21, 2020December 21, 2020 by Paul M. Sutter

This galaxy took only 500 million years to form

C1-23152 grew to 200 billion suns in just 500 million years. Image via INAF/ HST/ NASA/ ESA.

Galaxies are supposed to build up a very slowly, taking billions of years to acquire their vast bulk. But a newfound galaxy, appearing in the universe when it was only 1.8 billion years old, tells a different tale. It formed stars at a rate hundreds of times greater than the Milky Way, and was able to build itself up to host 200 billion stars in less than 500 million years – perhaps the universe’s greatest speed run.