Galactic Stripping Mystery Uncovered

Article written: 25 Jan , 2017
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It’s what you might call a case of galactic homicide (or “galacticide”). All over the known Universe, satellite galaxies are slowly being stripped of their lifeblood – i.e. their gases. This process is responsible for halting the formation of new stars, and therefore condemning these galaxies to a relatively quick death (by cosmological standards). And for some time, astronomers have been searching for the potential culprit.

But according to a new study by a team of international researchers from the International Center for Radio Astronomy Research (ICRAR) in Australia, the answer may have to do with the hot gas galactic clusters routinely pass through. According to their study, which appeared recently in The Monthly Notices of the Royal Astronomical Society, this mechanism may be responsible for the slow death we are seeing out there.

This process is known as “ram-pressure stripping“, which occurs when the force created by the passage of galaxies through the hot plasma that lies between them is strong enough that it is able to overcome the gravitational pull of those galaxies. At this point, they lose gas, much in the same way that a planet’s atmosphere can be slowly stripped away by the effects of Solar wind.

‘Radio color’ view of the sky above the Murchison Widefield Array radio telescope, part of the International Center for Radio Astronomy Research (ICRAC). Credit: Natasha Hurley-Walker (ICRAR/Curtin)/Dr John Goldsmith/Celestial Visions.

For the sake of their study, titled “Cold gas stripping in satellite galaxies: from pairs to clusters“, the team relied on data obtained by the Sloan Digital Sky Survey and the Arecibo Legacy Fast (ALFA) survey. While the SDSS provided multi-wavelength data on 10,600 satellite galaxies in the known Universe, ALFA provided data on the amount of neutral atomic hydrogen they contained.

By measuring the amount of stripping that took place within each, they deduced that the extent to which a galaxy was stripped of its essential gases had much to do with the mass of its dark matter halo. For some time, astronomers have believed that galaxies are embedded in clouds of this invisible mass, which is believed to make up 27% of the known Universe.

As Toby Brown – a researcher from the Center for Astrophysics and Supercomputing at the Swinburne University of Technology and the lead author on the paper – explained:

“During their lifetimes, galaxies can inhabit halos of different sizes, ranging from masses typical of our own Milky Way to halos thousands of times more massive. As galaxies fall through these larger halos, the superheated intergalactic plasma between them removes their gas in a fast-acting process called ram-pressure stripping. You can think of it like a giant cosmic broom that comes through and physically sweeps the gas from the galaxies.”

The Arecibo Observatory in Puerto Rico, where the Arecibo Legacy Fast ALFA Survey is conducted. Credit: egg.astro.cornell.edu

This stripping is what deprives satellites galaxies of their ability to form new stars, which ensures that the stars they have enter their red giant phase. This process, which results in a galaxy populated by cooler stars, makes them that much harder to see in visible light (though still detectable in the infrared band). Quietly, but quickly, these galaxies become cold, dark, and fade away.

Already, astronomers were aware of the effects of ram-pressure stripping of galaxies in clusters, which boast the largest dark matter halos found in the Universe. But thanks to their study, they are now aware that it can affect satellite galaxies as well. Ultimately, this shows that the process of ram-pressure stripping is more prevalent than previously thought.

As Dr. Barbara Catinella, an ICRAR researcher and co-author on the study, put it:

“Most galaxies in the Universe live in these groups of between two and a hundred galaxies. We’ve found this removal of gas by stripping is potentially the dominant way galaxies are quenched by their surroundings, meaning their gas is removed and star formation shuts down.”

Another major way in which galaxies die is known as “strangulation”, which occurs when a galaxy’s gas is consumed faster than it can be replenished. However, compared to ram-pressure stripping, this process is very gradual, taking billions of years rather than just tens of millions – very fast on a cosmological time scale. Also, this process is more akin to a galaxy suffering from famine after outstripping its food source, rather than homicide.

Another cosmological mystery solved, and one that has crime-drama implications no less!

Further Reading: Royal Astronomical Society, MNRAS

Matt Williams is the Curator of Universe Today’s Guide to Space. He is also a freelance writer, a science fiction author and a Taekwon-Do instructor. He lives with his family on Vancouver Island in beautiful British Columbia.

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6 Responses

  1. btraymd says

    Matt…once again current radio telescope data creates a “mystery” when viewed from the perspective of the gravity based standard model. This is consistent with the model’s lack of predictive value. The need for unobserved and unconfirmed theories (i.e. dark matter) to salvage the model should be white elephants in the room. It is time to discard this model rather than create mathematically derived concepts which have no basis in reality (based on observations or experimental validation) to salvage it. That is just good science. The electromagnetic model is being supported by all new radio telescope data, does not require unobserved theories ( black holes, dark matter) and conforms to the known laws of plasma physics and electrical engineering. Plus there is experimental evidence which supports the model. What more can you ask for????
    Keep these facts in mind when considering the field of cosmology. Plasma is being shown to be the fundamental material of which stars are constructed. Stars are surrounded by massive magnetic fields and these are accompanied by equally massive electric currents (flow of charged particles). The massive electromagnetic output of a star (i.e. our sun) arises from the plasma surface in the glow mode. “Photospheric granules” are now proven beyond all doubt to be Anode Tufts, they are not granules of anything. The infrared data from penumbra show a cool dark interior. Nothing happening in the core, the surface is where the action is. This explains a 5k surface temp with a 2 million coronal temp…..cannot possibly be a core driven scenario. The acceleration of charged particles as they approach earth can only happen in an electric field and again, invalidates the nuclear core theory.
    So look closely at Donald Scott’s model of star formation. The findings, as reported by the IBEX mission. of massive rivers of helium flowing into the sun from intergalactic sources is exactly what is predicted by the electromagnetic model. These findings are published in a series of 14 papers in the Astrophysical Journal Supplement, Oct 2015. These “rivers” are in fact the Birkeland currents that power the sun and all stars. The constriction of these currents by their magnetic fields is actually responsible for star formation. This explains why the sun is covered by plasma and massive magnetic fields.
    This model also explains the recent data showing star formation occurring along “filaments” in “star nurseries”. Once the electrical engineering principle of “Z Pinch” is fully comprehended by astronomers the model of star formation elegantly described by Dr. Scott will be accepted without debate.
    As far as ”black holes” are concerned, these galactic centers appear to be massive plasmoids in the dark mode. This model explains the massive emissions of electromagnetic energy in virtually all spectra including visible light. It also explains why they are surrounded by some of the most massive magnetic fields ever measured. These forces are responsible for galaxy formation. Singularity???? prove it. The forces of electromagnetism are infinitely more powerful than gravity and do not require any unobserved theories to account for galactic structure and function.
    I present these facts to offer a perspective that may change your way of thinking. You are obviously an intelligent guy and I hope you may begin to understand how scientifically disgusting the interpretations of recent data are using the the standard model as a framework.
    Of course the rejection of this model carries some unwanted baggage. I’m referring to the theory of relativity which was intellectually brilliant but has been essentially worthless in advancing our understanding of the universe. Even Albert expressed grave misgivings about the theory. Unfortunately, his disciples failed to recognize the reason for his misgivings. The theory requires the speed of light to be Vmax in the universe. When Albert recognized “spooky action at a distance” he knew that C was not Vmax. Tesla also saw the same thing and called the theory of relativity a “beggar in a purple robe”. The confirmation of the theory was based on findings referred to as the gravitational lensing which were based on the supposed “bending of light” by gravity during an eclipse. These findings were in fact due to diffraction. They are of course ridiculous since light has no mass and therefore cannot be influenced by gravity. Albert was a great thinker but his theories excluded the forces of electromagnetism and have taken the field of cosmology down a dead end road which has resulted in a science fiction that would make Jules Verne proud.

    • Code 80 says

      Interesting theory, I must say.

      • btraymd says

        The pioneers of the electromagnetic model will eventually be awarded the Nobel Prize. The contributions of Dr. Donald Scott are ground breaking. He was invited to speak at the NASA sponsored Goddard Colloquim on Engineering in 2009 and left the crowd in shock. He re-interpreted NASA data on a certain nebula clearly showing it was the birth of a star, not an explosion. View this presentation and you will be left stunned as were the astrophysicists in attendance.
        His newest publication which shows the modelling of Birkeland Currents and recent radio telescope data that confirms his model will be looked at as ground breaking for the next thousand years.
        Another future Nobel winner is Wal Thornhill…..one of the most plain spoken and intelligent scientists I have ever heard. His presentation ” The Long Road to Understanding Gravity” is awesome. It’s mind boggling to think that the entire gravity based standard model never comes close to discussing the force of gravity or from where it arises. The establishment has been content to ignore the nature of this force and assign it incredible values based on incredible densities, neither of which have ever been observed and both of which require a complete breakdown in the known laws of physics and chemistry.
        For example, the model of a neutron star of which has one teaspoon of mass which equals the mass of the entire earth. Is Anybody Listening??????? Isn’t it obvious that these ideas are so ridiculous that even the dumbest astrophysicist has to say ” Whaaaaat”‘.
        Scott coherently and succinctly explains the structure of these bodies and the mechanisms for their tremendous release of energy. And believe me when I say it has nothing to do with gravity.
        Back to gravity. According to Thornhill’s model it is a weak electromagnetic force….caused by subatomic dipole alignment. Makes sense. Explains why the gravity of the entire earth can be offset by 2 little bar magnets. Also explains why billions of tons of water can be suspended in our skies…..until lightening strikes (depolarization) and the water comes raining down.
        If you view both of these presentations you will see how badly the standard model is serving the scientific community.
        Ask yourself….with all the importance astrophysicists place on gravity…..why hasn’t any one tried to explain what it is or what causes it. I guess it’s out of respect for Isaac Newton, 300 years ago.

  2. btraymd says

    Furthermore, there are some very interesting mathematical proofs which raise serious questions about the standard model.
    Robillere has published a proof which invalidates the theorem governing black box radiation. This theorem was the basis for proposing the nuclear core theory of the sun. This comes as no surprise given the recent radio telescope data we have received from solar missions as I have elucidated above.
    Carrothers has also presented very convincing mathematical evidence which shows that the big bang theory and the black hole theory are mutually exclusive. He also inspected the math which led to the concept of a black hole. The Ric tensor used in the equations had a requirement that the universe was comprised of one body. This is clearly not valid and calls into question any concepts which are derived from it.
    But it should be overwhelmingly concerning when any scientific model is based solely on mathematics and has no observational or experimental evidence which support it. To report this model as factual and base other theories on this unproven hypothesis is dishonest and amoral.

    • Code 80 says

      Again, very interesting. I wonder what will come of more study on these hypotheses. This is the way science is supposed to work.

  3. btraymd says

    Now for the coupe de gras……Red Shift.
    Astronomers have blindly accepted that red shift is a measure of velocity and derived the big bang theory and universal expansion from this data
    It now appears that red shift is an intrinsic property of quasars based upon their age. This conclusion is based on data recently published by 2 separate groups showing markedly different red shifts fro quasars in the same galaxy.
    Lo and behold, this was also to be expected……if you believed Halton Arp and the data published in his book “Seeing Red”. Arp was a radio astrophysicist that studied under Hubble at the Max Planck Inst. He was called a “modern day Gallileo” at the time. Carl Sagan declared that if Arp’s data is confirmed it would invalidate the big bang theory. Arp was ostracized instead of invalidating the big bang model. The newest data shows he was correct.
    But the mainstream pushes on with their failed theories. I guess it’s about reputation and funding……casting scientific truth and true knowledge to the wayside. I imagine these guardians of the standard model feel that by making the model so preposterous and impossible to comprehend that it would be impossible to disprove.
    But they didn’t count on incredible advances in radio astronomy and enough people paying attention to the data. I, for one, have nothing to lose or gain by expressing my sincere opinions. I hold myself accountable to be honest and accurate in reflecting these opinions, to the best of my ability.
    As an M.D. with a natural interest in physics and cosmology as well as an above average education in the sciences I absolutely know the electromagnetic model deserves very serious consideration. It is long overdue to examine the reasons that the standard model has woefully failed to be supported by recent radio telescope data and been worthless as a predictive tool. It seems every day we observe new data which is a “”’mystery”. Now that is a mystery in itself.

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