"In recent years it has been discovered that these brown dwarfs can be extremely bright sources of radio emission. Up to now it has been unclear how these failed stars can produce such high levels of this nature of radiation. Initially, it was assumed that it was the same kind of radio emission as that detected from stars such as our Sun. For such stars, the radio emission is produced by high energy electrons in the star's corona which are trapped spiralling in the star's magnetic field.

However, our recent observations conducted with the Very Large Array radio telescope in New Mexico, together with optical telescopes at the US Naval Observatory and Vatican Observatory, have shown that this model is incorrect. We have detected extremely bright periodic pulses of radiation from a number of these objects which cannot be explained by the conventional processes associated with stellar radio emission. During these pulses, these supposedly failed stars are tens of thousands of times brighter than our Sun at radio frequencies! Instead a much more exotic process is required to explain such bright radio emission.

It turns out that the answer to this mystery is not to be found in the study of the radio emission from the stars but instead from the planets in our Solar System. All the magnetized planets, including Earth, are observed to emit extremely bright radio emission from their magnetic polar regions. Indeed, Jupiter can produce radio emission at low frequencies brighter than that detected from the Sun. This radiation is not produced by the same mechanism responsible for stellar radio emission but rather by a coherent process, the electron cyclotron maser, that can amplify the radiation to extremely high levels."

Is this what you're looking for?

Source.


I'm asking a question, VanRijn, and you answered with a question.
As I understand it, BD's radio emissions are, or can be, these very high energy electrons.


So, again, is there anyone else who thinks this "mysterious source" could be a BD?

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

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No. That is about radio emissions. not the generation of extremely high energy electrons as were detected.

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The Leif Ericson Cruiser

These radio emissions are the high energy electrons.
The electron cyclotron maser mechanism is what is thought to cause BDs to emit such radio waves, no?


Is there anyone else reading this that might clarify either VanRijn's question or my answer?

What am I missing?

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

No. Radio is EM radiation. Electrons are charged particles. They are not EM radiation.

(1)The ATIC finding was an excess of extremely high energy electrons (or positrons).

(2) You haven't presented a reference that indicates brown dwarfs generate these extremely high energy electrons.

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The Leif Ericson Cruiser

If I am reading the articles correctly, the ONLY evidence that the source is local is an unquestioning assumption that the majority of the 'Cosmic Microwave Background' is cosmic. The reasoning is thus: We know the cross section of the background and, based upon local physics, we know particles at these high energies cannot travel through space without colliding with 'CMB' background photons.

It has been established for some time that the source of cosmic rays is not known 'hot spots' within our own galaxy: If they were, the distribution of cosmic rays should somewhat mirror the distribution of matter, or at least star forming areas within the Milky Way galaxy; and that is not what we observe. Therefore they must be cosmic. But if cosmic rays are truly cosmic, both cosmic rays and the cosmic microwave background (CMB) cannot exist, unless the early measurements were in error and the cosmic ray energy spectrum does not extend beyond the GKZ cutoff.

The question that remained was whether cosmic rays truly exceed the GKZ cutoff; and this probe has apparently confirmed that they do. Since they 'can't' be cosmic, and they are not aligned with galactic features, these researchers are concluding that they are produced by dark matter collisions.

There are major problems with this reasoning: Why would dark matter collisions produce cosmic rays, but not multi-spectrum rays? How does dark matter, with no detectable baryon properties, convert dark matter into baryonic matter? What current, testable laws of physics does one invoke to reach these conclusions? If a new law is needed, why is only colliding dark matter an acceptable solution? It wouldn't require new physics to conclude there is a local source of the cosmic microwave background, it would only require a mechanism that is relatively local and in some way tied to the solar orbital plane (an observed feature in the "CMB").

The CMB has three features that were not expected/predicted: Anisotrophy, measurable three sigm 'hot' and 'cold' spots, and a dipole that aligns with the solar system. The CMB lacks the polarization predicted by inflation theory. More than one reasonable hypothesis can be drawn from these observational facts, including the hypothesis that most of the CMB may not be cosmic at all.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Jerry. Minor nitpick....positrons/electrons are not technically baryonic matter, as they are not baryons. The lightest baryon is the proton. Electrons/positrons are leptons..."light ones" with the muon and tau being the heavier members. Baryons consist of three quarks...leptons have none. Baryons must conserve baryon number in their decays,and have lepton number 0. Leptons conserve lepton number in their decays, have baryon number 0.
Lots of the dark matter popular writers address this lightly. There remains at present no experimental evidence that a normal hydrogen atom has appeared with a newly minted electron and a corroborating proton out of thin air....or contemporary cosmological vacuum. To do so, the Holy Grail of contemporary cosmology, would be the penultimate vindication of Fred Hoyle's original attack on the Big Bang....the generation of matter in a Steady State synthesis, from "empty space", itself. If that isn't irony, I don't know what is. pete

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I guess I need to do some reading because as I understand it, electrons are negatively charged particles and when accelerated they emit EM radiation.

1. Right, and what might be the source is the question.

2. Van Rijn, the spacedaily article in the OP states one of "The least exotic possibilities...(could be) a nearby pulsar" while the article I linked in #24 discusses BDs as a new class of pulsar. I'm unsure why you feel I needed to provide any more reference in order to ask what seems to be an obvious question.

Regarding BDs as pulsars:

"As yet, the processes controlling the radio flashes from TVLM 513 are still unclear. There is no evidence of a binary system, so interaction of the magnetosphere with a stellar wind from a nearby star seems an unlikely cause, nor is there any sign of an orbiting planet that could produce a scenario like that of Jupiter and Io. However, rapid rotation is also thought to be a source of electron acceleration for a component of Jupiter's maser emission and this may also be the main source of TVLM 513's radio flashes."

spaceref


So could a rapidly rotating nearby BD be the cause of these accelerated electrons?
Although, if there were a nearby BD it could just as well be the interaction of its magnetosphere with our sun's stellar wind, no?

I don't know which is why I ask...

But what do you think it might be, Van Rijn?
Dark Matter? A Black Hole?

Or, would you agree with Jerry and or pete that the CMB is not so "cosmic" and perhaps matter (these high energy electrons) is being generated nearby in emtpy space?

(that, if I'm understanding their discussion)

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"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

There is no indication that a brown dwarf would produce such extremely high energy electrons.

It would have to be from something that could produce extremely high energy electrons. That might be a black hole, neutron star, maybe dark matter.

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The Leif Ericson Cruiser

As exciting as this sounds and I may not be the best to comment on this due to my lack of knowledge in astronomy, but concidering no one knows what this is shouldn't it be cause for concern or am I missing something here.

Thanks

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Don't Hate Me Cause I Am Dum

You're missing something. Be concerned about things that can harm you.

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What i meant by concern is the source of this.

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Don't Hate Me Cause I Am Dum

No, there is no need to be concerned. Being concerned about getting hit by a car makes a lot of sense. But a source of gamma rays? Just for fun, suppose we discover it's a black hole that's going to devour our solar system. Do you think there's any way to deflect a black hole? It's best not to lose sleep worrying about things that are outside of our control.

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As above, so below

But if it is a black hole wouldn't we see part of the solar system be destroyed also at 3000 light-years away that is pretty far no

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Don't Hate Me Cause I Am Dum

That's probably not the best way to reassure bmpbmp. Let's be clear on this: We have not discovered a black hole that's going to devour our solar system.

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The Leif Ericson Cruiser

Bmpbmp, how many times have you asked the BAUT assemblage if you should be concerned by some latest cool discovery?

How many time was the answer yes?

Have you detected a pattern?

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So this being a black hole is a possibility then

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Don't Hate Me Cause I Am Dum

Which is attributable to what? You're not the only one who would like to know.

Screening out known contaminants is a tricky business.

That's funny - I heard just the opposite...

Hypothesize away. Be sure to indicate why the data necessitate your hypothesis.

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Everyone is entitled to his own opinion, but not his own facts.

No, I'm sorry I even said that, as Van Rijn already admonished me. I didn't mean to make any suggestion about what it might be, just that there's no point worrying about such things. I could have said, what if it's a Romulan starship? I just meant to say that if you spend your time worrying about whether each new discovery means the end of the universe is coming, you will make yourself sick.

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As above, so below

It is my understanding that cosmic rays above the GKZ cutoff have energy densities equivalent to baryons; that is, much heavier than leptons. (yes/no?)

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jwj

It's a big universe out there...is it really unwinding, really burning out?

The primary evidence that the CMB was primal was the uniform temperature. Evidence that it is less than uniform is contraindicative of the BB thesis. Since these variations are very small, they do not kill the theory, but they do invite alternative explanations.

...and assumptive: We just learned that magnetic reconnection events involves energy densities that are a full magnitude greater than predicted or expected. We learned in 1996 comets emit Xrays. Jupiter is a major source of microwaves; they were used to calibrate the WMAP probe, but nobody really knows why Jupiter is such a strong emitter. Saturn has almost global auroras, also a stunning surprise. The alignment of the oddball features in the CMB with the Zodiac is at least a strong caution flag: What else is going on out there?

The measured polarization is two magnitudes less than prior inflationary predictions; and in any case, there are known calibration weaknesses in both the WMAP and COBE probes. (WMAP relied upon COBE measurements to calibrate the primary antenna, COBE lacked a stable clock.) It will be interesting to see how the PLANCK background mapping compares with these earlier studies. If the calibration is independant of the earlier measurements, I don't think Planck will find the same signature.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

http://arxiv.org/abs/0812.3795v1

Foreground, in this study, would be an alignment with the galactic plane. I would argue ANY evidence of Isotropy should be regarded as evidence that the CMB as we observe it may not be BB residue, or at the least is badly contaminated. Remember, the CMB is offered as evidence of the BB exactly because it is not isotropic.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

http://arxiv.org/abs/0807.4880v3

...Which, if they are correct, means I=ATIC estimates of Cosmic ray energy levels are likely too high, and therefore they could travel intergalactly without attenuation by the CMB. The plot thickens...

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Van Rijn, I provided a couple of links to articles about TVLM 513, a brown dwarf, doing exactly that, producing high energy electrons.
The quote in #37 discusses possible causes for these accelerated electrons, these radio waves, from this brown dwarf.
A rather clear indication, no?

I see.
I'm disinclined to accept dark matter as an explanation, while I'm more inclined to think a neutron star could be so near our solar system rather than a black hole. Although, I think pulsar (rotating neutron star) could be as accurate a term. Something's accelerating those electrons and pulsars are known to do this. Of course, this leads me back to a new class of "pulsar," radio active brown dwarfs like TVLM 513.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

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...like southern gravy...

I feel like I'm promoting a somewhat conventional explanation!

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

Coincidentally Dissecting Pamela (and ATIC) with Occam's Razor: existing, well-known Pulsars naturally account for the "anomalous" Cosmic-Ray Electron and Positron Data

The popular media article you linked to said nothing about BDs producing 600+ Gev electrons and positrons.

I know this is simplistic. But, suppose this is a black hole after all, are there not other black holes closer to our solar system?

No. As I already said repeatedly, those did not discuss the generation of the extremely high energy electrons (or positrons) that are the subject of this thread. That's why I was asking you for references to support your brown dwarf claim.

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The Leif Ericson Cruiser

Hello, new poster. Welcome to BAUT.

I'm not sure I'm following your question, but if this is due to black holes, they would have to be within a few thousand light years.

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The Leif Ericson Cruiser

Hi timb.

Thanks.
Curious, if these findings are so simply explained why would they publish the results as "mysterious source" where the principal makes statements like "This electron excess cannot be explained by the standard of cosmic ray origin." ??



No, it did not; rather it was about BDs being pulsar like where the mechanisms for high energy electron acceleration are not fully understood.

To me it seemed a nearby pulsar, given as one explanation, lent validity to a nearby pulsar-like BD.
This is why I asked the question.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill