Mysterious “Lonely Cloud” Bigger Than Milky Way Found in a Galaxy “No-Man’s Land”

The orphan cloud is the blue umbrella-shaped part of this image, which is color-coded to show the X-ray part of the cloud in blue, the warm gas in red, and the visible region in white. Credit: Ge et al (2021)

A scientifically mysterious, isolated cloud bigger than the Milky Way has been found by a research team at The University of Alabama in Huntsville (UAH) in a “no-man’s land” for galaxies.

The so-called orphan or lonely cloud is full of hot gas with temperatures of 10,000-10,000,000 degrees Kelvin (K) and a total mass 10 billion times the mass of the sun. That makes it larger than the mass of small galaxies.

The cloud was discovered in Abell 1367 by a group led by Dr. Ming Sun, an associate professor of physics at UAH, which is a part of the University of Alabama System. Also called the Leo Cluster, A1367 contains around 70 galaxies and is located around 300 million light-years from Earth.

The research paper was led by Dr. Ming’s UAH postdoctoral researcher, Dr. Chong Ge, and the second author is also his postdoctoral researcher, Dr. Rongxin Luo. Dr. Sun is third author and the corresponding author. Also included on the paper is Tim Edge (MS, physics, 2019), who now works at Dynetics Inc.

The cloud was found using the European Space Agency (ESA) X-ray Multi-Mirror Mission (XMM-Newton), Europe’s flagship X-ray telescope. The cloud was also observed with the European Southern Observatory Very Large Telescope/Multi Unit Spectroscopic Explorer (VLT/MUSE) and Japan’s flagship optical telescope, Subaru.

“This is an exciting and also a surprising discovery. It demonstrates that new surprises are always out there in astronomy, as the oldest of the natural sciences.” Dr. Sun says. “Apparently, ESA agrees as our discovery was selected as an ESA image release, which has been very selective.”

XMM took the X-ray image of the cloud and the optical images were taken by VLT/MUSE and Subaru. Except for the Subaru images, Dr. Sun is the principal investigator for the XMM and VLT/MUSE data.

“The cloud was serendipitously discovered in our XMM data,” says Dr. Sun. “The optical data come from our VLT/MUSE data and confirm the cloud is located in the cluster.”

The cloud was discovered in a cluster of galaxies where thousands of galaxies are bound together with tenuous hot gas with temperatures of about 100,000,000 K existing between them, says Dr. Sun.

“However, the cloud is not associated with any galaxy and is in a ‘no-galaxy’s land,’” he says, adding that the cloud most likely originated from a large, unknown galaxy in the cluster.

“The gas in the cloud is removed by ram pressure of the hot gas in the cluster, when the host galaxy is soaring in the hot gas with a velocity of 1,000-2,000 kilometers per second.”

That’s about 50 times faster than the orbital speed of Earth around the sun. That level of force at work can rip the interstellar medium out of a galaxy, and in this case the researchers found that the temperature of the cloud is consistent with having originated from a galaxy.

“It is like when your hairs and clothes are flying backward when you are running forward against a strong headwind,” Dr. Sun says. “Once removed from the host galaxy, the cloud is initially cold and is evaporating in the host intracluster medium, like ice melting in the summer.”

Yet it is estimated that this massive, mysterious cloud has survived for hundreds of millions of years after removal from its host galaxy.

“This surprising longevity is poorly understood but may have something to do with the magnetic field in the cloud,” Dr. Sun says.

The field may act to hold the cloud together by suppressing unstable forces that would otherwise cause it to dissipate, the scientists think.

With future study, Dr, Ming says that the lonely cloud and others that are yet to be discovered could help scientists better understand stripped interstellar mediums at great distances from their galaxies, as well as the effects of turbulence and heat conduction.

“As the first isolated cloud glowing in both the H-alpha spectral line and X-rays in a cluster of galaxies, it shows that the gas removed from galaxies can create clumps in the intracluster medium, and these clumps can be discovered with wide-field optical survey data in the future.”

Reference: ” An H α/X-ray orphan cloud as a signpost of intracluster medium clumping” by Chong Ge, Rongxin Luo, Ming Sun, Masafumi Yagi, Pavel Jáchym, Alessandro Boselli, Matteo Fossati, Paul E J Nulsen, Craig Sarazin, Tim Edge, Giuseppe Gavazzi, Massimo Gaspari, Jin Koda, Yutaka Komiyama and Michitoshi Yoshida, 1 June 2021, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stab1569

AstronomyAstrophysicsEuropean Space AgencyPopularSubaru TelescopeUniversity of AlabamaXMM-Newton
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  • Real Morrissette

    Here’s the title: “Mysterious “Lonely Cloud” Bigger Than Milky Way…”
    Now here’s a second paragraph statement: “That makes it larger than the mass of small galaxies.”
    Since the Milky is a big galaxy of about 100 billion solar mass, it means the title of the article is wrong.

  • Patrick M Coyle

    Fantastic article ,unbelievable things happening out there , almost unsureal ! God is great, what a fantastic universe in motion !

    • Edward Armstrong

      Are you able to specify which particular ‘god’ out of the millions of ‘gods’ that humans have invented you are referring to and how you know that your preferred ‘god’ had anything to do with the origin of the universe?

    • Edward Armstrong

      Which ‘god’ is that again? You didn’t say.

  • Paul

    Real Morrissett, size can be measured in more than just mass. The Milky Way is 100,000 light-years across, has a mass of 100 billion solar-mass, and a volume of about 8 trillion cubic light-years. It’s reasonable to call the cloud “larger than the Milky Way” if it’s larger in diameter or in volume. Physicists tend towards the term “more massive” when describing mass.

  • Alan

    Why are all these scientists and educators Chinese? They have been infiltrating our education system for the past 20 years at all levels K-12 and beyond. They are the creators of the Critical Race Theory and thru subversion are looking to influence us from within shaping our social and political beliefs toward Communism. We were sold out by both political parties over many years and continues to this day with this Administration, which is the worst yet! They have taken over entire industries like our hotels and ski resorts. They own them all! In their latest attack they released a Virus they created in Wuhan. We are at WAR and we dont even know it!! Enough! Send these Chinese government agents of communism back to China! Tell them we don’t want them here and ship them back with all the politicians and others who took money back to China! GO BACK TO CHINA!

    • Edward Armstrong

      Notice the complete lack of any evidence for any of the claims in this rant. That is fairly typical for this sort of poster.