Fermi finds possible dark matter ties in Andromeda galaxy

February 21, 2017 by Claire Saravia
The gamma-ray excess (shown in yellow-white) at the heart of M31 hints at unexpected goings-on in the galaxy's central region. Scientists think the signal could be produced by a variety of processes, including a population of pulsars or even dark matter. Credit: NASA/DOE/Fermi LAT Collaboration and Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF

NASA's Fermi Gamma-ray Space Telescope has found a signal at the center of the neighboring Andromeda galaxy that could indicate the presence of the mysterious stuff known as dark matter. The gamma-ray signal is similar to one seen by Fermi at the center of our own Milky Way galaxy.

Gamma rays are the highest-energy form of light, produced by the universe's most energetic phenomena. They're common in galaxies like the Milky Way because , particles moving near the speed of light, produce when they interact with and starlight.

Surprisingly, the latest Fermi data shows the gamma rays in Andromeda—also known as M31—are confined to the galaxy's center instead of spread throughout. To explain this unusual distribution, scientists are proposing that the emission may come from several undetermined sources. One of them could be , an unknown substance that makes up most of the universe.

"We expect dark matter to accumulate in the innermost regions of the Milky Way and other galaxies, which is why finding such a compact signal is very exciting," said lead scientist Pierrick Martin, an astrophysicist at the National Center for Scientific Research and the Research Institute in Astrophysics and Planetology in Toulouse, France. "M31 will be a key to understanding what this means for both Andromeda and the Milky Way."

A paper describing the results will appear in an upcoming issue of The Astrophysical Journal.

Another possible source for this emission could be a rich concentration of pulsars in M31's center. These spinning neutron stars weigh as much as twice the mass of the sun and are among the densest objects in the universe. One teaspoon of neutron star matter would weigh a billion tons on Earth. Some pulsars emit most of their energy in gamma rays. Because M31 is 2.5 million light-years away, it's difficult to find individual pulsars. To test whether the gamma rays are coming from these objects, scientists can apply what they know about pulsars from observations in the Milky Way to new X-ray and radio observations of Andromeda.

NASA’s Fermi telescope has detected a gamma-ray excess at the center of the Andromeda galaxy that's similar to a signature Fermi previously detected at the center of our own Milky Way. Watch to learn more. Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger, producer

Now that Fermi has detected a similar gamma-ray signature in both M31 and the Milky Way, scientists can use this information to solve mysteries within both galaxies. For example, M31 emits few gamma rays from its large disk, where most stars form, indicating fewer cosmic rays roaming there. Because cosmic rays are usually thought to be related to star formation, the absence of gamma rays in the outer parts of M31 suggests either that the galaxy produces cosmic rays differently, or that they can escape the galaxy more rapidly. Studying Andromeda may help scientists understand the life cycle of cosmic rays and how it is connected to star formation.

"We don't fully understand the roles cosmic rays play in galaxies, or how they travel through them," said Xian Hou, an astrophysicist at Yunnan Observatories, Chinese Academy of Sciences in Kunming, China, also a lead scientist in this work. "M31 lets us see how cosmic rays behave under conditions different from those in our own galaxy."

The similar discovery in both the Milky Way and M31 means scientists can use the galaxies as models for each other when making difficult observations. While Fermi can make more sensitive and detailed observations of the Milky Way's center, its view is partially obscured by emission from the galaxy's disk. But telescopes view Andromeda from an outside vantage point impossible to attain in the Milky Way.

"Our galaxy is so similar to Andromeda, it really helps us to be able to study it, because we can learn more about our galaxy and its formation," said co-author Regina Caputo, a research scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It's like living in a world where there's no mirrors but you have a twin, and you can see everything physical about the twin."

While more observations are necessary to determine the source of the gamma-ray excess, the discovery provides an exciting starting point to learn more about both galaxies, and perhaps about the still elusive nature of dark matter.

"We still have a lot to learn about the gamma-ray sky," Caputo said. "The more information we have, the more information we can put into models of our own galaxy."

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Hyperfuzzy
1.8 / 5 (5) Feb 21, 2017
All sources of radiation are due to the motion of charge. Dark Matter?
baudrunner
1 / 5 (1) Feb 21, 2017
M31 is 2.537 million light years away. What I see in that image coming from the center of the largest galaxy in our immediate group with three times as many stars as in our own Milky Way and over twice its size, is a high concentration of energy coming from a relatively small field of view which instruments have compacted into an image that fits on top of this article. I don't think that there is a precedent for DM being a candidate for why it looks like this to us and any physicist would be hard-pressed to describe the mechanism whereby this would be the case, as we have no empirical evidence to back this idea up. The comparative γ ray curve for the two probably shows a steeper curve as the size of a galaxy increases and on the cosmic scale, M31 is relatively close to us.
Benni
1.6 / 5 (7) Feb 21, 2017
"We expect dark matter to accumulate in the innermost regions of the Milky Way and other galaxies, which is why finding such a compact signal is very exciting," said lead scientist Pierrick Martin, an astrophysicist at the National Center for Scientific Research...."

Odd, isn't it? In the 1930's Dark Matter godfather Fritz Zwicky used just the reverse logic for locating accumulations of DM. His hypothesis was that we should expect that DM would exist in giant enveloping halos surrounding Spiral Galaxies, ostensibly functioning as a counter gravitational force preventing the spiral & radial arms from imploding into the central hub.

So now what do we have? Just the reverse hypothesis. So now what does Pierrick Martin think prevents Spiral Galaxies from imploding if the DM is concentrated in the "innermost regions of the Milky Way", a spiral galaxy. I guess he forgot to read Zwicky's paper.
howhot3
2.3 / 5 (3) Feb 21, 2017
Anyone interested in Dark Matter (DM) should Google "Emergent Gravity" (EG) and see if observations fit with in that theoretical framework. The compartmentalization of the Gama sources to the core of the galaxies certainly does imply the space/time curvature is steeper, and more energetic, it also implies the link EG has to 3D spacetime curvature. The obvious is the concentration of gravity to major wells, like the center of galaxies, implicates DM or in the case of EG a more energetic compacted quantum distribution of space.
RealityCheck
3.6 / 5 (14) Feb 22, 2017
Oh FFS!

Is there a 'science' paper-writing & journalism "service" that all these astrophysicists/cosmologist go to for "ghost writing"?

They all grasp at the 'exotic' DM 'straw', using it at the drop of a hat, probably to 'grease it' past the 'peer review' and 'journal editors' to 'guarantee' publication!

When will this exotic' DM BABBLEGAF 'interpretation/speculation' STOP already!

We've had recent discoveries where Galactic dynamics follows closely the ORDINARY matter concentrations/dynamics; which means any 'exotic' DM woud be distributed co-moving/colocated with ORDINARY matter. But we DON'T SEE any great additional NON-ordinary mass effects spread through the galaxy!

Now it's supposed to be concentrated in the galactic nucleus region! But we still don't see any extreme gravitational mass/dynamics there either!...other than black hole, nucleus stars/plasma/dust!

IF there was 4 TIMES ADDITIONAL MASS ANYWHERE in our galaxy, GR dynamics would be EXTREME.

STOP IT!
Da Schneib
4 / 5 (4) Feb 22, 2017
We must find out how to focus gamma rays better than this.
Benni
2 / 5 (4) Feb 22, 2017
The obvious is the concentration of gravity to major wells, like the center of galaxies, implicates DM or in the case of EG a more energetic compacted quantum distribution of space.


Well no kidding that you'll find greater concentrations of gravity at the centers of galaxies, it's OBSERVATIONALLY obvious that's where most of the MASS is.

You completely overlook Zwicky's hypothesis, that ALL DM would be found in halo envelopes SURROUNDING the entire Spiral Galaxy as the COUNTER GRAVITATIONAL ATTRACTION to the central hubs ostensibly for the purpose of preventing the arms of the galaxy from imploding into the central hubs, but Pierrick Martin completely misses this.

bschott
3 / 5 (2) Feb 22, 2017
This is a pretty hard kick in the balls to a theory that requires it to be distributed in a halo in order to explain the rotation curve of the visible matter that the imaginary substance was first hypothesized to do....or...like everything else they try to use DM to explain, they are wrong.

But lets think about this from the standpoint that they are correct and the emission is from DM....how much more does there now have to be in the halo to explain the rotation curve? How does something transparent to radiation emit radiation again?

BTW I am not looking for debate. Just for the DM enthusiasts to answer the questions in a scientifically proven manner...in other words, not a theory to explain a theory. Any hard data that makes this nonsense even close to possible.
RNP
3.9 / 5 (7) Feb 22, 2017
@Benni
You completely overlook Zwicky's hypothesis, that ALL DM would be found in halo envelopes SURROUNDING the entire Spiral Galaxy as the COUNTER GRAVITATIONAL ATTRACTION to the central hubs ostensibly for the purpose of preventing the arms of the galaxy from imploding into the central hubs.

You COMPLETELY misunderstand EVERYTHING!

1) Zwicky did not discuss spiral galaxies.

2) He discussed the Coma cluster, about which in 1933 he said:
"In order to obtain the observed value of an average Doppler effect of 1000 km/s or more, the average density in the Coma system would have to be at least 400 times larger than that derived on the grounds of observations of luminous matter." I.e. DM PERVADES the cluster, not surrounds it.

3) You do not understand physics if you think surrounding a galaxy with matter can "prevent the arms of the galaxy from imploding". It is CERTAINLY not why DM is required to explain galaxy dynamics.

You really should learn some physics.
Hyperfuzzy
1 / 5 (4) Feb 22, 2017


You really should learn some physics.

So should you. The intensity of the field is due only to distance, the energy is due to the frequency, the entire wave is the wrinkle in the field due to the motion of the center of the field. The more intense motion, or superfast orbiters imply smaller orbits. How small can an orbiter be? So gamma ray burst may be the product of anti-matter and matter collision, note the different orbiters and there speed.

It would be wise to review the "doppler" measure.
Benni
1 / 5 (5) Feb 22, 2017
But lets think about this from the standpoint that they are correct and the emission is from DM....how much more does there now have to be in the halo to explain the rotation curve? How does something transparent to radiation emit radiation again?


It's all due to magical properties imbuing DM with properties of morphing into & out of various states of detection. If it's inside the galaxy it can emit photons, if it's outside the galaxy it morphs into magical properties preventing photon emission.

You see, DM Enthusiasts like to imagine they are on the cutting edge of science, this is to say that what we learned in the college classroom about SR & GR is just too stifling & creates roadblocks to the advancement of Astro-physics.

It's a really good observation you made about EM emission from DM. I guess the guy putting this forth was just not smart enough to figure he'll be caught with that mistake. Maybe RNP can explain it for us , he's a good journalist.

Benni
1 / 5 (4) Feb 22, 2017
1) Zwicky did not discuss spiral galaxies.

2) He discussed the Coma cluster, about which in 1933 he said:
"In order to obtain the observed value of an average Doppler effect of 1000 km/s or more, the average density in the Coma system would have to be at least 400 times larger than that derived on the grounds of observations of luminous matter." I.e. DM PERVADES the cluster, not surrounds it.

3) You do not understand physics if you think surrounding a galaxy with matter can "prevent the arms of the galaxy from imploding". It is CERTAINLY not why DM is required to explain galaxy dynamics.

You really should learn some physics.


......and you should learn what Zwicky actually wrote rather than trying to convince the readers here he never proposed Envelopes of DM surrounding Spiral galaxies. You're so mis-educated that you don't even know what your DM godfather wrote back in the 1930's & why he got tagged with that handle of "Zany Zwicky".

SlartiBartfast
5 / 5 (6) Feb 22, 2017

......and you should learn what Zwicky actually wrote rather than trying to convince the readers here he never proposed Envelopes of DM surrounding Spiral galaxies. You're so mis-educated that you don't even know what your DM godfather wrote back in the 1930's & why he got tagged with that handle of "Zany Zwicky".


Fritz Zwicky once risked his own life to rescue 37 drowning kittens. He also built 4 orphanages (in addition to taking in over 2 dozen orphans into his own home). Truly a great man.
Da Schneib
5 / 5 (4) Feb 22, 2017
Actually, the dark matter "halos" are theorized to be roughly ellipsoidal and of fairly uniform density throughout. The misconception that they are toroids is common and not founded on either observations or modelling.

Zwicky never proposed or discussed dark matter halos, and neither did Vera Rubin, the co-discoverer of the flat rotation curves of spiral galaxies. These halos were proposed after numerical simulations of galaxy formation in the early universe were done.

Lenni's making stuff up again.
howhot3
2.3 / 5 (4) Feb 23, 2017
Well the problem with DM is that it doesn't make sense. If it's some kind of neutral barionic material it should be detectable, just as the neutron is. DM is not detectable other than it's effect on gravity wells. DM by all measurements appears to be a variable of gravity that is related to density of matter in an area. If the laws of Newton and Einstein are out of bounds, then there must be an additional physics being missed. Emergent Gravity theory pretty much fits this. Why don't you guys look at it? Seriously it fits experiment.
Da Schneib
5 / 5 (4) Feb 23, 2017
I've had a look at Emergent Gravity; particularly, at Verlinde's paper of last November. There is some evidence to support it, but Verlinde at the end says it's far too early to conclude that it's capable of explaining things like the acoustic oscillations in the CMB and the observed cosmological evolution. With more work, it might turn out to be consistent, or it might not. Time will tell.
RNP
5 / 5 (6) Feb 23, 2017
@Benni
......and you should learn what Zwicky actually wrote rather than trying to convince the readers here he never proposed Envelopes of DM surrounding Spiral galaxies. You're so mis-educated that you don't even know what your DM godfather wrote back in the 1930's & why he got tagged with that handle of "Zany Zwicky".


AS usual, your post is PURE FABRICATION.
1) Zwicky NEVER talked about DM in or around spiral galaxies.
2) These "envelopes" surrounding galaxies you keep referring to are inventions of your own. Nobody with any scientific understanding would consider such obvious nonsense.
3) YOU are the only one that refers to Zwicky as "Zany".

From experience I know that it is almost certainly pointless, but, nevertheless, I challenge you to find ANY references to support your silly claims.

BTW. Please note that your usual mindless response of "....prove it" will only serve to prove MY point, as, if you HAD any proof of your claims, you would surely give it.
Hyperfuzzy
1 / 5 (1) Feb 23, 2017
So, no one studies or really understand what the collection of experiments that defined Maxwell's equations imply. Rather, a very poor understanding of what a constant is within an equation and how it relates to reality. We seem to rely heavily upon our "belief" systems and not physics or logic. The entire 20th century was an exercise in fantasy. Are we going to continue this foolishness? Well, OK for SYFY but, think, this is becoming laughable.
Hyperfuzzy
1 / 5 (1) Feb 23, 2017
Mass is an experimental constant not a property; the speed of light is how fast the charge is updated relative to its center, not universal; QM was our best guess, not theory since all studies seemed to show the wave equation, so we define potential and kinetic energy very well; however non-causal. No axiom, no empirical evidence, no well thought out theory, do not throw away causality or make up stuff because we do not know how to count!
FineStructureConstant
5 / 5 (5) Feb 25, 2017
@hyper - you appear to be getting fuzzier all the time. Better try to hold on to something solid now, before you disappear into the fog of your own delusions.
Hyperfuzzy
not rated yet Feb 25, 2017
@hyper - you appear to be getting fuzzier all the time. Better try to hold on to something solid now, before you disappear into the fog of your own delusions.

Explain. Or do you understand?
Da Schneib
5 / 5 (5) Feb 25, 2017
@hyper, having actually read your comments I have to say that they appear to be negative information: that which, when you know it, reduces your understanding.

You appear to be denying the existence of mass. This is ludicrous.
FineStructureConstant
5 / 5 (3) Feb 26, 2017
@hyper - Explain? - in your case, that simply can't be done: "it takes two to tango", and you're alone and out of touch, deaf to reason, in your own poorly-lit basement of ineffectuality, twisting and gyrating to the weird cacophony that only you can hear.
Or do you understand?
Que?
Hyperfuzzy
not rated yet Feb 26, 2017
OK, I do understand. 1 Kg is made of 1/(Me +Mp) charges. These charges produce the field that Newton did not have with him to explain where the field originated. How do you get this field from the experimental constant. Because we do it over and over again does not make it so. We can't even definitively define the Gravitation constant. Anyway, it is ludicrous, the entire modern physics would require a rewrite. I like to start with the axiom: There only exist the diametrical spherical fields, apparently never created or destroyed, etc. etc. No Mass
Hyperfuzzy
not rated yet Feb 26, 2017
So keep what we have; just know, it probably will not work everywhere! However, please remove QM, GR, and the SM and all!
Da Schneib
5 / 5 (4) Feb 26, 2017
I like to start with the axiom: There only exist the diametrical spherical fields, apparently never created or destroyed, etc. etc. No Mass
So you really meant it.

This is kind of like the old George Carlin joke, "And now for tomorrow's weather... there will be no weather tomorrow."

It's amusing, but it fails the most obvious of tests; we can measure both gravitational and inertial mass classically. In fact, we can measure inertial mass in the quantum realm, and when we add up these measured masses we get the correct classical result. Keep in mind that the SM is Special Relativistic, and mass is well defined in Special Relativity (not to mention its progenitor, Newton's Laws of Motion).

You might as well claim there is no such thing as light.

This is silliness, and there's little point in responding further.
Hyperfuzzy
not rated yet Feb 26, 2017
So keep what we have; just know, it probably will not work everywhere! However, please remove QM, GR, and the SM and all!


Yes, we do these calculations while ignoring the obvious. Mass, inertia, ... Higgs? Really? But I'm in error. All my calculations are from these without the false assumptions, just the facts and nothing but the facts
Hyperfuzzy
not rated yet Feb 26, 2017
OK, I do understand. 1 Kg is made of 1/(Me +Mp) charges. These charges produce the field that Newton did not have with him to explain where the field originated. How do you get this field from the experimental constant. Because we do it over and over again does not make it so. We can't even definitively define the Gravitation constant. Anyway, it is ludicrous, the entire modern physics would require a rewrite. I like to start with the axiom: There only exist the diametrical spherical fields, apparently never created or destroyed, etc. etc. No Mass

Calculation is for the number of charge pairs using existing science as best guess.
Hyperfuzzy
not rated yet Feb 26, 2017
I like to start with the axiom: There only exist the diametrical spherical fields, apparently never created or destroyed, etc. etc. No Mass
So you really meant it.

This is kind of like the old George Carlin joke, "And now for tomorrow's weather... there will be no weather tomorrow."

It's amusing, but it fails the most obvious of tests; we can measure both gravitational and inertial mass classically. In fact, we can measure inertial mass in the quantum realm, and when we add up these measured masses we get the correct classical result. Keep in mind that the SM is Special Relativistic, and mass is well defined in Special Relativity (not to mention its progenitor, Newton's Laws of Motion).

You might as well claim there is no such thing as light.

This is silliness, and there's little point in responding further.

So dark matter is not silly?
Whydening Gyre
not rated yet Feb 26, 2017
I like to start with the axiom: There only exist the diametrical spherical fields, apparently never created or destroyed, etc. etc. No Mass
So you really meant it.

This is kind of like the old George Carlin joke, "And now for tomorrow's weather... there will be no weather tomorrow."

I always thought it was, "... will depend on whether tomorrow comes..."

It's amusing, but it fails the most obvious of tests; we can measure both gravitational and inertial mass classically. In fact, we can measure inertial mass in the quantum realm, and when we add up these measured masses we get the correct classical result. Keep in mind that the SM is Special Relativistic, and mass is well defined in Special Relativity (not to mention its progenitor, Newton's Laws of Motion).

a Diametric field that DOES something is BECAUSE it has mass (of some variety) generating that field.
HF is caught in the "Chicken or Egg" blender...
I choose - the blender.
Hyperfuzzy
5 / 5 (1) Feb 27, 2017
it really matters only for precision. We created this measure 'cause stuff kept falling; so, we blame the stuff. It would not change the fact that it's due to the nature of space, a set of diametrical spherical fields. You don't need my permission to call it mass or quarks. But I must take exception to dark matter.

Einstein was very imaginative; however, I blame his first wife. Her name was also on the original paper. However, "macho" had it removed.

Anyway, a mass of spherical fields are the real reason the apple fell! "Macho" prefers to call it mass and assign to charge. So the entire conversation is without logic. meh!
bschott
3 / 5 (2) Feb 27, 2017
If I am following what Hyper is saying correctly with regards to mass and charge: He is speaking about how gravity is nothing more than induced magnetic attraction between classically "neutral" bodies (which are just groupings of + and - charges) and how mass is an induced magnetic effect...it has merit.
If you take a 10lb iron ball, it requires 10 pounds of force to keep it off the surface of the earth...the further away from the earth you move it the less force is required. Hold that ball 1 ft from a reasonably powerful and "heavy" permanent magnet on the ground and now you need more than 10 pounds of force to keep the ball off the surface...the induced magnetic field between the magnet and the ball increases the relative mass between both objects...despite the fact that there is no change in how much matter is present in either object.

This sounds more like the physics of our universe than "depressions" in the "fabric" of "spacetime" caused by mass effect on said fabric.
Da Schneib
3 / 5 (2) Feb 27, 2017
it really matters only for precision.
It really only matters if you...

wait for it...

GET ON A SCALE

Duhhh ummm.
Whydening Gyre
5 / 5 (1) Feb 28, 2017
If I am following what Hyper is saying correctly with regards to mass and charge: He is speaking about how gravity is nothing more than induced magnetic attraction between classically "neutral" bodies

only "neutral" relative to the environment it is located WITHIN. Meaning, they are not really neutral, just less effective in surrounding environment.
(which are just groupings of + and - charges) and how mass is an induced magnetic effect...it has merit.

It does.
However, the quantative values of + and - is of importance. We LIVE in an truly analog Universe.
Everything changes it's relative effect, geometrically dependent of it's quantitive value.
To carry it further, Gravity is what happens when enough "polarized" magnetic bits collect together. Their directional attraction gradually becomes "unpolarized"and will exhibit in all directions (perpendicular to the center). due to their angular position relative to each other.
layers and scale...
Hyperfuzzy
not rated yet Feb 28, 2017
We have named the field an E field, magnetism is a derivative of field, we only see the wrinkles in the field and not all the wrinkles and forget about the massive field we do not see. If you get it, you realize that a proper correction will require the entire industry.

I prefer computer programs for meds, microchips, sensors, etc.. Knowing what we measure is key! Much better when you know.

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