Mysterious signal from the center of the Perseus Cluster unexplained by known physics


Astronomers using NASA's Chandra X-ray Observatory to explore the Perseus Cluster, a swarm of galaxies approximately 250 million light years from Earth, have observed the spectral line that appears not to come from any known type of matter. The signal they received can not be explained by known physics but they say it shifts suspicion to the dark matter.

Perseus Cluster a collection of galaxies and one of the most massive known objects in the Universe, immersed in an enormous 'atmosphere' of superheated plasma. It is approximately 768 000 light years across.

perseus cluster

Perseus Cluster. Image credit: Credit: NASA / Chandra

"I couldn't believe my eyes," says Esra Bulbul of the Harvard Center for Astrophysics.  "What we found, at first glance, could not be explained by known physics."

"The cluster's atmosphere is full of ions such as Fe XXV,  Si XIV, and S XV.  Each one produces a 'bump' or 'line' in the x-ray spectrum, which we can map using Chandra. These spectral lines are at well-known x-ray energies."

Yet, in 2012 when Bulbul added together 17 day's worth of Chandra data, a new line popped up where no line should be.

"A line appeared at 3.56 keV (kilo-electron volts) which does not correspond to any known atomic transition," she says.  "It was a great surprise."

The spectral line appears not to come from any known type of matter. Image credit: NASA / Chandra

"It took a long time to convince myself that this line is neither a detector artifact, nor a known atomic line," Bulbul said. "I have done very careful checks.  I have re-analyzed the data; split the data set into different sub groups; and checked the data from four other detectors on board two different observatories. None of these efforts made the line disappear."

In short, it appears to be real.  The reality of the line was further confirmed when Bulbul's team found the same spectral signature in X-ray emissions from 73 other galaxy clusters. Those data were gathered by Europe's XMM-Newton, a completely independent X-ray telescope.

Moreover, about a week after Bulbul team posted their paper online, a different group led by Alexey Boyarsky of Leiden University in the Netherlands reported evidence for the same spectral line in XMM-Newton observations of the Andromeda galaxy.  They also confirmed the line in the outskirts of the Perseus cluster.

"After we submitted the paper, theoreticians came up with about 60 different dark matter types which could explain this line. Some particle physicists have jokingly called this particle a 'bulbulon'," she laughs.

The menagerie of dark matter candidates that might produce this kind of line include axions, sterile neutrinos, and "moduli dark matter" that may result from the curling up of extra dimensions in string theory.

There is uncertainty in these results, in part, because the detection of this emission line is pushing the capabilities of both Chandra and XMM-Newton in terms of sensitivity. ​

More data and investigation will be needed to confirm both the signal's existence and nature.

Perseus Cluster. Image credit: NASA / Chandra; ESA / XMM-Newton

A paper describing the detection of this mysterious emission line was published in the July 1st issue of The Astrophysical Journal and a preprint is available online.

Source: NASA / Chandra

Featured image: Chandra X-ray Observatory. Image credit: NASA

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  1. Did a little digging, researched a bit, and you know what I found that 3.56 keV is in the SX (Soft X-ray) range. Now why is that important? Well, we use X-rays for a variety of things, such as Crystallography, Mammography, CT scans, and even In airports. In the soft X-ray range one of devices to produce this particular type is an X-ray Laser. This is just a hypothesis but what if it is artificially created? With a bit of looking you can learn that X-rays have a remarkable ability to penetrate most forms of matter. Especially low density materials, if given a near direct line of sight with sparse clouds of dust and gas it would stand to reason that using X-rays would be more beneficial than standard visible light. The Perseus Cluster falls under this catagory, on sight the cloud of plasma seems to be a thick soupy mass that blocks most of the light emanating from the cluster. But switch to X-rays and everything clears up. Consider this a theory. Honestly, we've got a ways to go before we see any Dark matter, our equipment is about 100-200 years behind what it should be for that, give it another 50 years and the proper funding and we should see the beginnings of Dark matter detectors, 50 years after that we'll be collecting and using the stuff for whatever. Have fun, Stay safe, and We are always watching you.

  2. Dont ger excited..subhumans, Darkmater is simply a hole in the space-time continuum,just like a hole in streched chewing gum.I found a lot of those traveling on old american highways.Now that u have the solution..do yur maths!!!

  3. It's happening again. Just when I think I've found a safe galaxy to live in, some schmartypants scientist starts looking around until he finally locates my "people"–whom I had hoped to never see again. Next they'll be trying to establish contact with them and before you know it, Earth is up to its eyeballs in intergalacic tourists. That's it. I ain't waiting around to watch it happen again. I'm outta here.

  4. Ey how many timee have the most seemingly reveloutiinary discoveries been just minor misses. Like faster than light nutrinos and the exo-planets that were just sunspots. Never underestimate or overlook the obvious.

  5. How do we know so much about the ions in an atmosphere that far away, but when a plane goes missing in the backyard on mother Earth, everyone is left scratching their heads.

  6. So, you are telling me you are a an astrophysicist or some sort of scientist but you fail to plot the units on the Y axis of your plot?? I'm sorry, but you come across as more of a salesperson or marketing manager…. A.K.A. post the f@C<!#G units or your data is s#!T

    1. Casey,
      If you're that brilliant, you'd be analyzing the data firsthand. Until you complete your second Ph.D. in Astrophysics, simply sit back and enjoy your position as an "arm chair quarterback."

    1. Any chance of it being caused by a resonance or constructive interference. ? Passing thought. No ot a serious doubt. I love a new discovery and a good mystery

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