Rare monster galaxy grew rapidly 12 billion years ago … then suddenly died

News
By Mike Wall
published

Astronomers don't know why the monster's star-birth engine shut down.

These three panels show, from left to right, what the galaxy XMM-2599's evolutionary trajectory might be, beginning as a dusty star-forming galaxy, then becoming a dead galaxy, and perhaps ending up as a "brightest cluster galaxy," or BCG.
These three panels show, from left to right, what the galaxy XMM-2599's evolutionary trajectory might be, beginning as a dusty star-forming galaxy, then becoming a dead galaxy, and perhaps ending up as a "brightest cluster galaxy," or BCG. (Image credit: NRAO/AUI/NSF/B. Saxton; NASA/ESA/R. Foley; NASA/StScI.)

Astronomers just discovered a rare monster galaxy that grew rapidly in the universe's early days — and then went quiet surprisingly fast.

The newfound giant, known as XMM-2599, lies about 12 billion light-years from Earth, meaning that scientists are seeing the galaxy as it existed when the universe was quite young. (The Big Bang that created the universe occurred 13.82 billion years ago.)

“Even before the universe was 2 billion years old, XMM-2599 had already formed a mass of more than 300 billion suns, making it an ultramassive galaxy," Benjamin Forrest, a postdoctoral researcher in the Department of Physics and Astronomy at the University of California Riverside (UCR), said in a statement. 

"More remarkably, we show that XMM-2599 formed most of its stars in a huge frenzy when the universe was less than 1 billion years old, and then became inactive by the time the universe was only 1.8 billion years old," added Forrest, the lead author of a new study reporting the discovery of XMM-2599.

Related: Our expanding universe: age, history and other facts

Forrest and his colleagues used an instrument called the Multi-Object Spectrograph for Infrared Exploration (MOSFIRE), which is installed on a telescope at the Keck Observatory in Hawaii. The MOSFIRE observations allowed the team to nail down XMM-2599's mass and its distance from Earth.

The researchers also determined that the galaxy created more than 1,000 suns' worth of stars every year during its activity peak. (For comparison, our Milky Way is currently forming just one solar mass of new stars annually.) But that peak is in the rearview mirror for XMM-2599; its star-birth engine has shut down, for reasons that remain unclear.

"Even though such massive galaxies are incredibly rare at this epoch, the models do predict them," study co-author Gillian Wilson, a physics and astronomy professor at UCR who heads the lab in which Forrest works, said in the same statement. 

"The predicted galaxies, however, are expected to be actively forming stars," Wilson added. "What makes XMM-2599 so interesting, unusual and surprising is that it is no longer forming stars, perhaps because it stopped getting fuel or its black hole began to turn on. Our results call for changes in how models turn off star formation in early galaxies."

The researchers will continue to observe XMM-2599 using Keck, in an attempt to better characterize the galaxy and investigate unanswered questions about it. The most prominent such question may concern the galaxy's fate.

"We do not know what it will turn into by the present day," Wilson said. "We know it cannot lose mass. An interesting question is what happens around it. As time goes by, could it gravitationally attract nearby star-forming galaxies and become a bright city of galaxies?"

The new study was published online Wednesday (Feb. 5) in The Astrophysical Journal Letters.

Mike Wall's book about the search for alien life, "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook. 

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Mike Wall
Mike Wall
Senior Space Writer

Michael Wall is a Senior Space Writer with Space.com and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.

6 Comments Comment from the forums
  • rod
    Admin said:
    Astronomers just discovered a rare monster galaxy that grew rapidly in the universe's early days — and then went quiet surprisingly fast.

    Rare monster galaxy grew rapidly 12 billion years ago … then suddenly died : Read more

    As the abstract link reports, "z = 3.493" for XMM-2599 galaxy. Using the cosmology calculators, COSMOLOGY CALCULATORS, XMM-2599 exists today at nearly 23E+9 light-years distance based upon Big Bang expansion and light-time using Special Relativity vs. the look back time used in the report (something not commonly reported). Presently, telescopes cannot verify what XMM-2599 is now or how it evolved, according to the Big Bang model. Spitzer surveys show cosmic high noon in star formation reached near z=3.0, after that a rapid drop off in star formation takes place across the universe. We see this in the globular clusters plotted on the H-R star diagram as an example. The Big Bang model features a distinct beginning and z surveys (redshift) show rapid star formation changes, like XMM-2599 in the early universe, i.e. dramatically changing and slowing down. It does appear that the 2nd Law/entropy is winning, the universe is winding down from the *beginning* and is not winding up :)
    Reply
  • Stephen J. Bauer
    I believe the article misses the point. What our observation are providing to us is a window into what the universe was like 12 billion years ago. This means that this hypothetically 'dead' galaxy has 12 billions years to evolve to where we are now, in the present. It may be that this observed activity is just a precursor to galactic development as we view it today. While the majority of the galaxies are expected to form between 500 million to 1 billion years after the Big Bang, I would guess that not all development should necessarily fall within this window. It may be that some galactic developments are more staggered than cosmologists have projected.

    Additionally, if you accept the idea that the observable universe is like a message in a bottle that is cast into the sea, then you would realize that such calculations and measurements are limited to how one can observe the cosmos. Understanding that radiated signals, like light, can travel independent of their source, then one can logically hypothesize that there is no way of knowing when a radiated signal enters into our field of view. But the expectation is that the light is traveling faster than the expansion rate. Where this is not true, then the light will never reach us.

    Considering that light travels faster than the expansion rate, then the limit of our observable perspective has been identified as about 14 billon light years, give or take a few billion years, depending on the instruments used. What we may not fathom is that the radiated signal may have been traveling for trillions of light years before it even entered into the field of our observable universe.

    Example of visible distant not being the same as actual distance: Imagine the farthest observable distance. The CMB is visible at a distance of 13.8 billion years. If we could travel that distance, we would find planets similar to our own. Looking back from this distance, from where Earth should be, we would only observe this fog of the CMB. From this new distant location, 13.8 billion light years from Earth, we could leap-frog another 13.8 billion light years to observe a whole new cosmography. And there is no theory or calculation to preclude our ability to do this again and again, on into infinity. So scientists need to qualify their measurements as from within the observable universe, when discussing either its size or age. This does not diminish the importance of these calculations and measurements, but it does diminish their premise of conjecture for the entirety of the universal cosmology and cosmogony of its existence.
    Reply
  • Torbjorn Larsson
    This complex messy subject of star and galaxy development is at the current research edge of modeling https://www.sciencemag.org/news/2018/05/galaxy-simulations-are-last-matching-reality-and-producing-surprising-insights-cosmic ]. Seems that long ago - about a year ago :-D - they still had not figured out that early star formation was fast even though astrophysicists told them it was the natural rate for molecular clouds. It is today's active galaxy nuclei feedback rate that is sloven,

    So I wouldn't know the classification of "supermassive" which likely is a bit fuzzy, what would be informative would be to have a graph over the observed mass distribution.

    But to start take a whack on it, here is a lump of galaxies at the 2 billion years universe age distance: "the protocluster SPT2349-56 ... the most active region that scientists have observed in space ... SPT2349-56 contains the mass of around 10 trillion suns. Computer simulations show that the 14 galaxies will combine ..."
    https://www.techtimes.com/articles/226184/20180427/giant-collision-of-14-young-galaxies-12-billion-years-ago-shows-formation-of-galaxy-cluster-in-early-universe.htm ]
    So, a very active - fast growing, merging - region with ~ 100 billion stars per galaxy on average, compared with 300 billion stars for the most extreme outlier yet found. The explanation for the rapid cutoff in star formation is what is now lacking. More work for the scientists.
    Reply
  • Torbjorn Larsson
    Stephen J. Bauer said:
    I believe the article misses the point. ... It may be that some galactic developments are more staggered than cosmologists have projected.
    ...
    So scientists need to qualify their measurements as from within the observable universe, when discussing either its size or age. This does not diminish the importance of these calculations and measurements, but it does diminish their premise of conjecture for the entirety of the universal cosmology and cosmogony of its existence.

    I'm not sure the article - or science - misses the point since less distant galaxies inform on the intermediate and current development of galaxies.

    Nor is the implied observations of, well, the observable, universe necessary to point out. Your gedanken experiment is impossible to realize, and I think you misunderstand the physics anyway. The future horizon define the observable universe - the largest volume we will ever see - by dint of accumulated local expansion eventually sum up to overtake the local universal speed limit (light speed in vacuum) at distances far enough from us. Everything that isn't gravitationally bounded - galaxies farther away than our Local Group of galaxies or currently 10 million light years (100 times larger than our 0.1 Mlyrs diameter Milky Way) - will eventually expand out over the horizon and become invisible (too much redshifted to see). Conversely, nothing will pass in over the current horizon. (Note that during inflation - when there were no objects - and at early eras of our big bang - Hubble rate expansion - universe, there was some interesting dynamics between internally observed putative objects and the light vs horizon history. But after and into the future, it will not be the case based on observed cosmology.)

    But essentially our cosmology show that the universe is homogeneous and isotropic to wide distances anyway. Just from cosmic variance in the observations of the cosmic background spatial spectra we can say that the local universe is at least 100 times larger in volume than the observable universe. From the current uncertainty in flatness we can say that the local universe is at least 10 million times larger in volume (if I did the math correctly). And from Planck 2018 observing eternal, slow roll, inflation and nothing else (and given that flat space is an observation not touched by the remaining tension in local Hubble rate), the inflationary universe is most likely (less constraint) infinitely large - even if our local universe is not.

    "Cosmogony" is mostly religion; I take it. With slow roll inflation it is, again, most likely no initial state of inflation when observers look back. It always was, is and will be, and it would always generate habitable pockets (or we wouldn't be here - survival bias).
    Reply
  • danR
    Here is the (2019) pre-print draft:
    https://arxiv.org/pdf/1910.10158.pdf
    Reply
  • Paul001
    Admin said:
    Astronomers just discovered a rare monster galaxy that grew rapidly in the universe's early days — and then went quiet surprisingly fast.

    Rare monster galaxy grew rapidly 12 billion years ago … then suddenly died : Read more
    Could it be that the monster galaxy was composed of monster stars that rapidly went supernova with the resulting remnants having jets that blew away the interstellar medium?
    Reply