Mapping the magnetic bridge between our nearest galactic neighbours

May 12, 2017, University of Sydney
The Large (centre left) and Small (centre right) Magellanic Clouds are seen in the sky above a radio telescope that is part of the Australia Telescope Compact Array at the Paul Wild Observatory in New South Wales, Australia. Credit: Mike Salway

For the first time, astronomers have detected a magnetic field associated with the Magellanic Bridge, the filament of gas stretching 75 thousand light-years between the Milky Way Galaxy's nearest galactic neighbours: the Large and Small Magellanic Clouds (LMC and SMC, respectively).

Visible in the southern night sky, the LMC and SMC are dwarf that orbit our home galaxy and lie at a distance of 160 and 200 thousand light-years from Earth respectively,

"There were hints that this magnetic field might exist, but no one had observed it until now," says Jane Kaczmarek, a PhD student in the School of Physics, University of Sydney, and lead author of the paper describing the finding.

Such can only be detected indirectly, and this detection was made by observing the radio signals from hundreds of very distant galaxies that lie beyond the LMC and SMC. The observations were made with the Australia Telescope Compact Array radio telescope at the Paul Wild Observatory in New South Wales, Australia.

"The radio emission from the distant galaxies served as background 'flashlights' that shine through the Bridge," says Kaczmarek. "Its magnetic field then changes the polarization of the . How the polarized light is changed tells us about the intervening magnetic field."

A radio signal, like a light wave, oscillates or vibrates in a single direction or plane; for example, waves on the surface of a pond move up and down. When a radio signal passes through a magnetic field, the plane is rotated. This phenomenon is known as Faraday Rotation and it allows astronomers to measure the strength and the polarity—or direction—of the field.

The observation of the , which is one millionth the strength of the Earth's, may provide insight into whether it was generated from within the Bridge after the structure formed, or was "ripped" from the dwarf galaxies when they interacted and formed the structure.

"In general, we don't know how such vast magnetic fields are generated, nor how these large-scale magnetic fields affect galaxy formation and evolution," says Kaczmarek. "The LMC and SMC are our nearest neighbours, so understanding how they evolve may help us understand how our Milky Way Galaxy will evolve."

"Understanding the role that magnetic fields play in the evolution of galaxies and their environment is a fundamental question in astronomy that remains to be answered."

The paper is one of a growing number of new results that are building a map of the Universe's magnetism. According to Prof. Bryan Gaensler, Director of the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, and a co-author on the paper, "Not only are entire galaxies magnetic, but the faint delicate threads joining galaxies are magnetic, too. Everywhere we look in the sky, we find magnetism."

The paper appeared in the Monthly Notices of the Royal Astronomical Society.

Explore further: Giant magnetic fields in the universe

More information: J. F. Kaczmarek et al. Detection of a Coherent Magnetic Field in the Magellanic Bridge through Faraday Rotation, Monthly Notices of the Royal Astronomical Society (2017). DOI: 10.1093/mnras/stx206 , On Arxiv:

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2.7 / 5 (11) May 12, 2017
Much Much less need for DM/DE when simple magnetism and electric fields over vast spaces are considered. Yes, they have small strength but with the huge pervasive size and the timespan it has to work in, it seems to fit the bill rather nicely.

However, you cannot make the big money by telling politicians that it is magnetism that needs to be measured, instead they build these monstrosities of undergound sites to find these seemily undetectable particles costing several millons to billions of dollars. It may well be they do not exist, that the answer has been staring us in the face all along.
2.7 / 5 (13) May 12, 2017
Mapping the magnetic bridge between our nearest galactic neighbours

In other words, they are mapping the electric currents connecting the galaxies.
2.1 / 5 (11) May 12, 2017
Thank you for publishing work from a scientist who lives in the real world. You'd almost think this guy understands the science beyond the math.....

...........but Schneibo should be along shortly to explain why his Inferred Gravity math for DM far exceeds this observation.

Or RNP will be along to explain why DM albeit is scattered so thinly throughout the Universe that it can't be detected, yet which creates forces of gravity without which most gravitational lensing cannot occur.

The observations of science will just need to continue moving on leaving the Funny Farm Science crowd to wallow in their favorite lands of fantasy.
4.9 / 5 (10) May 12, 2017
Mapping the magnetic bridge between our nearest galactic neighbours

In other words, they are mapping the electric currents connecting the galaxies.

Which galaxy of the two has the higher electric potential and why?
Where is the current sinking?
Where is the current sourced?
1.9 / 5 (8) May 12, 2017
691Boat, it is possible to favor the electric current explanation without even knowing what the answers to those questions are. But, if you insist, my understanding is that in a general sense, currents are generally flowing from low redshift objects into high redshift objects, for the simple reason that the age component of redshift is thought, within the electrical view, to be more significant than the recessional velocity component. That logic comes from the fact that we only see redshift periodicity completely wash out in regions where we know for sure that the objects are traveling at enormous speeds.

Also: if Arp is correct, it may very well be that quasars are born electron-deficient, and the filament which connects them to their parent -- as well as the surrounding space -- will then provide electrons into the proto-galaxies and even galaxies just to balance things out.

As for why it all occurs, I refer you to your local church.
1.8 / 5 (8) May 12, 2017
Realize that if Arp is correct, it should be possible to establish galactic lineages to some number of generations ... perhaps becoming more speculative the further you go back, but a combination of the redshift values and axial tilts could in theory feed into a simulation of the Arp model and generate a lineage for the known universe.

I'm quite sure that once all of this wacky stuff we see today is set aside, we're going to see some serious efforts put into that.

This could at least inform us if the universe is growing in a particular direction -- which some might argue indicates a beginning somewhere (?).

I suspect though that future generations will have a more realistic perception about the limits of what science can tell us.
1 / 5 (8) May 13, 2017

Which galaxy of the two has the higher electric potential and why?

It doesn't matter. One is at a higher potential than the other because it is the Suns that are creating charge, and each one a different level of charge, and (coventioanally) there are many stars in the galaxies.
Where is the current sinking?

Charge, whatever that really is, hates being crowded, it will move towards somewhere less crowded, with as little of half a volt difference being all that is needed. So as each galaxy accumulates charge, it is going to be seeking to look for easier living, it reaches out to its 'desired', they move towards each other.
Where is the current sourced?

Current is present when there is a flow of charge between these two galaxies. The bonds , the attraction, strengthen as more charge flows over time. Eventually the bond becomes so strong, the tension ruptures the twisted longitudinal magnetic field, an arc occurs, the Light shines forth, a star is born.

2.3 / 5 (9) May 14, 2017
Which galaxy of the two has the higher electric potential and why?
Where is the current sinking?
Where is the current sourced?

The key is that they are different, just as when you reach for the doorknob.
As HA pointed out, it is likely that quasars are electron deficient and they are drawing them from the parent galaxy.
Also, the Birkeland currents are most likely coaxial, i.e., they contain reversing flows;
as such, electrons flowing one way, protons the other way.
1.7 / 5 (6) May 15, 2017
Solon please refrain from trying to explain the concepts of any plasma cosmology theory until you have a complete understanding of them. I am a huge advocate and can see obvious flaws in your statements. This allows any outsider or opponent to the 'EU' to take your words as a common mindset among all of us, which only belittles the ideology.

Just remind the audience of the basics which drew yourself to the EU. In this case, there is a magnetic field linking the galaxies, nobody can argue that. ONLY electric currents can produce magnetic fields so there MUST be electric fields present, this is a fact.

There is not enough scientific effort throughout the community to answer the "why" questions yet. Proponents of the EU do not have the solutions to these foundational dilemmas, however, that does not discredit the ideas. Just imagine if the same level of motivation emanated in plasma cosmology as it does in finding why gravity exists, all of these answers would be at our fingertips.
4.3 / 5 (6) May 15, 2017
there you have it..... "ideology"......basics which drew you to it........not enough scientific effort throughout the community to answer the "why" questions.....

All earmarks of delusion. Religious belief systems. Believe it, then try to explain it.
2.1 / 5 (7) May 15, 2017
And you are any different zzzzz? Your particular ideology seems to be that it is ok to harrass and disrespect folks that hold to different scientific notions than you do; that you subscribe to the whole Big Bang theology of creation, which also relies on a rather impossible set of situations to come about. Something from Nothing. That sort of goes against the whole thermodynamic conservation theory, does it not?

Ideology, where it is subscribing to a specific type of view concerning a scientific, social or political idea (such as those of Capitolism, communism, creationism or individual Political Parties platforms), is very different than taking that theory and making it a Theology that explains God. The Big Bang idea is a Christian idea based in the Genesis 'Let There Be Light'. from Nothing, and sets a 'hard' start date that may or may not line up with actual observations or those observations have been wrongly interpreted, which is most of what we have been trying to point out.
2.1 / 5 (7) May 15, 2017
Believe it then try to explain it describes the mainstream paradigm to a tee.

Believe everything is gravitationally attracted to each other, observe everything moving away from each other and invent dark energy. Believe galaxies rotate gravitationally, observe them rotating too fast and with uniform velocity, invent dark matter to explain it.

Confirmational bias is far too pervasive and theories which represent the foundation of GR are now entirely ad hoc.

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