Arrested development: Hubble finds relic galaxy close to home

March 12, 2018, NASA's Goddard Space Flight Center
[Upper right] --This is a Hubble Space Telescope image of galaxy NGC 1277. The galaxy is unique in that it is considered a relic of what galaxies were like in the early universe. The galaxy is composed exclusively of aging stars that were born 10 billion years ago. But unlike other galaxies in the local universe, it has not undergone any further star formation. Astronomers nickname such galaxies as "red and dead," because the stars are aging and there aren't any successive generations of younger stars. The telltale sign of the galaxy's "arrested development" lies in the ancient globular clusters that swarm around it. The reddish clusters are the strongest evidence that the galaxy went out of the star-making business long ago. Otherwise, there would be a lot of blue globular star clusters, which are largely absent. The lack of blue clusters suggests that NGC 1277 never grew further by gobbling up surrounding galaxies. [Background image] -- The galaxy lives near the center of the Perseus cluster of over 1,000 galaxies, located 240 million light-years away from Earth. NGC 1277 is moving so fast through the cluster, at 2 million miles per hour, that it cannot merge with other galaxies to collect stars or pull in gas to fuel star formation. In addition, near the galaxy cluster center, intergalactic gas is so hot it cannot cool to condense and form stars. Credit: NASA, ESA, M. Beasley (Instituto de Astrofísica de Canarias), and P. Kehusmaa

Astronomers have put NASA's Hubble Space Telescope on an Indiana Jones-type quest to uncover an ancient "relic galaxy" in our own cosmic backyard.

The very rare and odd assemblage of stars has remained essentially unchanged for the past 10 billion years. This wayward stellar island provides valuable new insights into the origin and evolution of billions of years ago.

The galaxy, NGC 1277, started its life with a bang long ago, ferociously churning out stars 1,000 times faster than seen in our own Milky Way today. But it abruptly went quiescent as the baby boomer stars aged and grew ever redder.

The findings are being published online in the March 12 issue of the science journal Nature.

Though Hubble has seen such "red and dead" galaxies in the early universe, one has never been conclusively found nearby. Where the early galaxies are so distant, they are just red dots in Hubble deep-sky images. NGC 1277 offers a unique opportunity to see one up close and personal. "We can explore such original galaxies in full detail and probe the conditions of the early universe," said Ignacio Trujillo, of the Instituto de Astrofisica de Canarias at the University of La Laguna, Spain.

The researchers learned that the relic galaxy has twice as many stars as our Milky Way, but physically it is as small as one quarter the size of our galaxy. Essentially, NGC 1277 is in a state of "arrested development." Perhaps like all galaxies it started out as a compact object but failed to accrete more material to grow in size to form a magnificent pinwheel-shaped galaxy.

Approximately one in 1,000 massive galaxies is expected to be a relic (or oddball) galaxy, like NGC 1277, researchers say. They were not surprised to find it, but simply consider that it was in the right place at the right time to evolve - or rather not evolve - the way it did.

The telltale sign of the galaxy's state lies in the ancient globular clusters of stars that swarm around it. Massive galaxies tend to have both metal-poor (appearing blue) and metal-rich (appearing red) globular clusters. The red clusters are believed to form as the galaxy forms, while the blue clusters are later brought in as smaller satellites are swallowed by the central galaxy. However, NGC 1277 is almost entirely lacking in blue globular clusters. "I've been studying globular clusters in galaxies for a long time, and this is the first time I've ever seen this," said Michael Beasley, also of the Instituto de Astrofisica de Canarias.

The red clusters are the strongest evidence that the galaxy went out of the star-making business long ago. However, the lack of blue clusters suggests that NGC 1277 never grew further by gobbling up surrounding galaxies.

By contrast, our Milky Way contains approximately 180 blue and red globular clusters. This is due partly to the fact that our Milky Way continues cannibalizing galaxies that swing too close by in our Local Group of a few dozen small galaxies.

It's a markedly different environment for NGC 1277. The galaxy lives near the center of the Perseus cluster of over 1,000 galaxies, located 240 million light-years away. But NGC 1277 is moving so fast through the cluster, at 2 million miles per hour, that it cannot merge with other galaxies to collect stars or pull in gas to fuel star formation. In addition, near the galaxy center, intergalactic gas is so hot it cannot cool to condense and form .

The team started looking for "arrested development" galaxies in the Sloan Digital Sky Survey and found 50 candidate massive compact galaxies. Using a similar technique, but out of a different sample, NGC 1277 was identified as unique in that it has a central black hole that is much more massive than it should be for a galaxy of that size. This reinforces the scenario that the supermassive black hole and dense hub of the galaxy grew simultaneously, but the galaxy's stellar population stopped growing and expanding because it was starved of outside material.

"I didn't believe the ancient galaxy hypothesis initially, but finally I was surprised because it's not that common to find what you predict in astronomy," Beasley added. "Typically, the universe always comes up with more surprises that you can think about."

The team has 10 other candidate galaxies to look at with varying degrees of "arrested development."

The upcoming NASA James Webb Space Telescope (scheduled for launch in 2019) will allow astronomers to measure the motions of the globular clusters in NGC 1277. This will provide the first opportunity to measure how much dark matter the primordial galaxy contains.

Explore further: Image: Hubble catches galaxies swarmed by star clusters

More information: The primordial red globular cluster system of NGC 1277, Nature (2018). nature.com/articles/doi:10.1038/nature25756

Related Stories

Image: Hubble catches galaxies swarmed by star clusters

October 2, 2017

In the center of a rich cluster of galaxies located in the direction of the constellation of Coma Berenices, lies a galaxy surrounded by a swarm of star clusters. NGC 4874 is a giant elliptical galaxy, about ten times larger ...

Hubble digs into cosmic archaeology

October 30, 2017

This NASA/ESA Hubble Space Telescope image is chock-full of galaxies. Each glowing speck is a different galaxy, except the bright flash in the middle of the image which is actually a star lying within our own galaxy that ...

Image: Hubble's compact galaxy with big-time star formation

October 16, 2017

As far as galaxies are concerned, size can be deceptive. Some of the largest galaxies in the Universe are dormant, while some dwarf galaxies, such as ESO 553-46 imaged here by the NASA/ESA Hubble Space Telescope, can produce ...

Image: Hubble checks out a home for old stars

December 21, 2015

This image, taken with the Wide Field Planetary Camera 2 on board the NASA/ESA Hubble Space Telescope, shows the globular cluster Terzan 1. Lying around 20,000 light-years from us in the constellation of Scorpius (The Scorpion), ...

A lot of galaxies need guarding in this NASA Hubble view

May 4, 2017

Much like the eclectic group of space rebels in the upcoming film Guardians of the Galaxy Vol. 2, NASA's Hubble Space Telescope has some amazing superpowers, specifically when it comes to observing innumerable galaxies flung ...

Recommended for you

Sprawling galaxy cluster found hiding in plain sight

August 16, 2018

MIT scientists have uncovered a sprawling new galaxy cluster hiding in plain sight. The cluster, which sits a mere 2.4 billion light years from Earth, is made up of hundreds of individual galaxies and surrounds an extremely ...

Hubble paints picture of the evolving universe

August 16, 2018

Astronomers using the ultraviolet vision of NASA's Hubble Space Telescope have captured one of the largest panoramic views of the fire and fury of star birth in the distant universe. The field features approximately 15,000 ...

Unusual doughnut-shaped jet observed in the galaxy NGC 6109

August 15, 2018

Astronomers from the University of Bristol, U.K., have uncovered an unusual doughnut-shaped jet in the radio galaxy NGC 6109. It is the first time that such a jet morphology has been observed in a low-power radio galaxy. ...

Iron and titanium in the atmosphere of an exoplanet

August 15, 2018

Exoplanets, planets in other solar systems, can orbit very close to their host stars. When the host star is much hotter than the sun, the exoplanet becomes as hot as a star. The hottest "ultra-hot" planet was discovered last ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

dfjohnsonphd
1 / 5 (4) Mar 12, 2018
They say something has remained essentially unchanged for the past 10 billion years. But how could they know? We have only been watching the cosmos with semi-sophisticated instruments for about 100 years. How can anyone say that nothing has happened to anything, anywhere, for the past 10 billion years? Seems a tad presumptuous to me.
Tuxford
2 / 5 (4) Mar 13, 2018
They say something has remained essentially unchanged for the past 10 billion years. But how could they know? We have only been watching the cosmos with semi-sophisticated instruments for about 100 years. How can anyone say that nothing has happened to anything, anywhere, for the past 10 billion years? Seems a tad presumptuous to me.

Indeed. Just propagating the fantasy to unsettled minds. Useless speculation in this story.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.