All Questions
Tagged with neutrinos astrophysics
53 questions
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Angular momentum of matter halos?
How much momentum (or more specifically, angular momentum) could a matter halo (like a dark matter halo, a neutrino halo...) have? Is it possible that they may have high amounts of momentum?
For ...
- 2,878
3
votes
0
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223
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How do you build a Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) detector?
*Milkjug-sized neutrino detector (the COHERENT neutrino detector):
https://news.uchicago.edu/story/worlds-smallest-neutrino-detector-observes-elusive-interactions-particles#:~:text=The%204%2Dinch%...
- 47
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55
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Can there be structures made from neutrinos that can have angular momentum?
Would it be possible to eventually have structures made from neutrinos somewhere in the universe, as it is indicated in this question (Are neutrino stars theoretically possible?), like halos of ...
- 2,878
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1
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58
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Incompatibility of constraints set by MAGIC ICAT telescope on NGC 1068 neutrinos flux with observation by IceCube
Data from the MAGIC ICAT telescope, when used to provide constraints on the neutrino flux from NGC1068, predicts maximal event rate of neutrino detection to be about 0.07 per year. As described in the ...
- 195
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44
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Statistical significance for longer measurement
I recently read that icecube neutrino detector measured neutrinos emmitted from the direction of NGC1068, which is a nearby Active Galactic Nucleus which has reported an excess
of neutrinos from that ...
- 195
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2
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Sun light takes 1,000/30,000/100,000/170,000/1,000,000 years bouncing around inside to then reach the Earth
When light (photon particle) is generated inside the Sun, it takes a long time to bounce around inside to later escape and travel outwards.
Neutrinos escape immediately.
The numbers for the years ...
- 548
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1
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139
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Solar neutrino spectrum: why are there two lines for beryllium?
I have a follow-up question to this one:
Solar neutrino Spectrum - Why are there discrete energies for Be and pep?
I understand why the lines for $^{7}\text{Be}$ and $pep$ are discrete, but why do we ...
- 65
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116
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Why is the scientific community, and especially the astrophysicists, so skeptical about sterile neutrinos?
As rob pointed out in a comment in my previous question :
"There were hints about sterile or missing neutrinos in LSND, in the low-statistics region of MiniBoone, and in a number of other ...
- 4,448
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4
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462
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How can the Cosmic Neutrino Background (CνB) have a temperature? How can any neutrino have a 'temperature'?
The word temperature usually refers to the average velocity of massive particles, correct?
And the Cosmic Microwave Background (CMB) has a 'temperature' based on the temperature of a 'black body' that ...
- 4,709
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63
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Why do we need hot dark matter?
Data on galaxy rotation curves suggested that not all the mass in the galaxy is accounted for and we can't observe them directly but remind me again why we need hot dark matter in the first place? ...
- 13.1k
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494
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What causes neutrino thermal radiation?
Often in astrophysics, I see neutrino particles being considered as photons, in the sense that hot material emits neutrino thermal radiation.
There are a lot of similarities of neutrino and photon ...
- 111
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2
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105
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Are there papers or experiments that point to non-fusion sources of solar neutrinos?
I've read that nuclear fusion is what generates such large quantities of solar neutrinos.
Also saw that it was recently experimentally confirmed that two types/energies of neutrinos are generated in ...
3
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3
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354
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Why don't the nuclear fusion processes inside the sun produce electron antineutrinos $(\bar\nu_e)$?
Why don't the nuclear fusion processes inside the sun produce $\bar\nu_e$ despite having the same mass as $\nu_e$? Is the reason as simple as "there is no production channel for $\bar\nu_e$s.&...
- 27.2k
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Deriving the free streaming distance for HDM particles
I am trying to derive the free-streaming length for the HDM particles but I couldnt follow the arguments given by the article https://arxiv.org/pdf/astro-ph/0201405v1.pdf after equation 83.
Thanks
- 3,160
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2
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How do we exactly use neutrinos to probe the core of the Sun (if they can only interact weakly)?
Neutrinos are interacting with ordinary matter weakly. They pass through matter mostly unimpeded.
Thus, neutrinos typically pass through normal matter unimpeded and undetected.
Neutrinos' low ...
- 29.3k
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How many $pep$-related electron-neutrinos $\nu_e$ does the Sun produce?
In the sun neutrinos can be produced by the rare proton-electron-proton (pep) reaction:
$$ {}^1_1 H + e + {}^1_1 H \to {}^2_1 H + \nu_e $$
How many pep-related electron neutrinos does the Sun ...
2
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1
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42
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A search for IceCube events in the direction of ANITA neutrino candidates
In regards to the recent discover by ANITA of space-bound high energy Neutrinos, could this possibly be explained by atmospheric Beta Decay reactions producing these Neutrinos in between the IceCube ...
- 21
4
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2
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719
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Are the muon/tau neutrinos produced in the Sun? If not, then where?
I was reading about Solar Neutrinos, and apparently they are all Electron Neutrinos.
However, there are two other types of neutrinos, the Muon and Tau Neutrinos. Does the Sun produce them? If not, ...
- 704
4
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1
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194
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Neutrino production in supernovae
As much as 99% of the gravitational energy liberated in a core collapse supernova emerges as kinetic energy of neutrinos. The neutrinos are produces in nuclear reactions (electron capture on nuclei ...
- 1,169
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44
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The basics of neutrino telescopes
I'm trying to understand the basic operation of the ANTARES neutrino telescope. Here is what I've gathered:
The detection of neutrinos relies upon the detection of muons.
Cosmic rays and neutrinos ...
5
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2
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98
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What caused neutrinos to decouple at $t=1$ second?
Was it simply that the density and/or kinetic energy got too low, because of expansion? Or was it something about the weak force itself (which I thought gelled around $10^{-10}$s?
For the CMB, ...
- 578
2
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1
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179
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What's up with these new high energy neutrinos?
A bunch of pop science articles just popped up talking about new high-energy neutrino detection. See this article, published today, for example. The answer to this question says that the source of ...
- 251
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Electron density in the Sun
I'm currently working on solar neutrino and in order to make a numerical simulation, I need the potential felt by electron-neutrino :
\begin{equation}
V_e(r) = \sqrt{2} G_F N_e(r)
\end{equation}
where ...
- 75
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66
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Do stellar model luminosities include neutrino losses?
I have had a sudden crisis in my understanding of the published outputs from stellar evolutionary model calculations.
Usually these models output a "luminosity" that one can then use, along ...
- 136k
3
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1
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296
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Solar neutrino Spectrum - Why are there discrete energies for Be and pep?
What is the reason why some reactions give a continuum for the energy of the released neutrinos and others give only a discrete value ($\ ^7B$ and $pep$ )?
Thanks for your help. Please feel free to ...
- 653
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1
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104
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In the Homestake experiment, why did they alternate runs with $^{36}\rm Ar$ and $^{38}\rm Ar$?
In the Homestake experiment, why did they alternate runs with $^{36}\rm Ar$ and $^{38}\rm Ar$? I understand why they use a carrier isotope like $^{36}\rm Ar$ or $^{38}\rm Ar$ to mesure the efficiency ...
- 59
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2
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200
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Can high energy galactic neutrinos harm us?
The neutrinos that are generated from the supernova are in the order of Peta eV, which is very large; when they reach the earth surface and get contact with earthly bodies, do they make any harm, if ...
- 347
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Why do the neutrinos (with mass) from a supernova arrive before the light (no mass)?
I've already read the below questions (and their answers) regarding neutrinos vs. electromagnetic waves propagating through space, but I'm still not clear on something.
Neutrinos arrived before the ...
- 1,867
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229
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Could black holes resemble cold neutrino stars?
A question about falling into a "neutrino star" led me to think about the physics of such an object, and to discover that there are already papers on the subject.(2000 2001)
I was struck by the way ...
- 13.4k
9
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1
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501
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Can I stand on a neutrino star?
Hypothetically, if neutrinos lost their energy in the expanding universe, slowed down, and collapsed in a vast and otherwise empty region under their own gravity, they might form a large object ...
- 12.9k
-4
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243
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Hydrogen fusion in the Sun-neutrino
One of the ways nuclear fusion happens in the sun is deuterium and tritium fusion which forms a Helium-4 atom and a neutrino. What flavor of neutrino is created - a tau, muon, or electron neutrino?
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2
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351
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Is it possible that black holes have an anti-matter jet? [closed]
If we can think of the black hole in the center of our galaxy as a group of decaying atoms with neutrinos coming from one side in the jet and anti neutrinos from the other side then would it be ...
- 1
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1
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How much of neutrinos pass through a neutron star?
Neutrino rarely interact with matter however neutron star is extremely dense and I suppose only an insignificant amount of neutrinos can pass through the densest object in the universe second to black ...
- 13.1k
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2
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306
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Are Black Holes Neutrino Factories?
Are Black Holes Neutrino Factories? That is.. are they an intense source of neutrinos? If so, then the center of almost every galaxy would be a neutrino factory.
- 355
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3
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937
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How would cold neutrinos get trapped by stars?
Continuing on from the cool physics Q&A'd on the threads Where are all the slow neutrinos?, Is it possible that all "spontaneous nuclear decay" is actually "slow neutrino" ...
- 135k
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94
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Is it possible that cosmic ray particles and neutrinos account for a significant portion of dark matter?
Sounds a bit naive but I read somewhere that neutrinos were thought to account for dark matter to an extent and I think Zwicki came up with the idea before cosmic rays were announced (not sure though)....
- 1,562
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2
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159
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Measuring the size of the core of the sun with multiple neutrino detectors
Back in 1998, researchers at the Super-Kamiokande neutrino detector released this image:
of the sun using their neutrino detector using approximately 500 days of data. This picture covered 90x90 ...
- 545
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1
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316
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Where do astrophysical neutrinos come from?
What I really do not get about them is collisions of cosmic rays with light produces high energy neutrinoes but cosmic rays have a little energy maybe less than a 5000 electron volt. How do high ...
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1
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112
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What is the gravitational power that neutrinos created in the big bang exert on us?
I was thinking about the big bang, and I remembered that neutrinos not only travel at the speed of light, but they were also created in massive quantities very early in the universe (Hadron epoch).
...
0
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1
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127
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What is the bigger number of particles crossing an area: the number of photons or the number of neutrinos? [closed]
Take an squared area with (10²)² m² in front of the sun. What is the bigger number of particles crossing an area: the number of photons or the number of neutrinos?
Just for clarification: you can ...
- 407
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1
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276
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In what ways does the sun output energy?
I'm curious about the energy output of the sun, and how it breaks down. What fraction is from EM radiation, solar wind, neutrinos, et cetera? How does energy output vary over the EM spectrum?
I was ...
- 124
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2
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Free neutrons in the sun's core?
In the standard description of proton-proton fusion, the first step of the interaction proceeds through the unbound diproton $\rm^2He$:
$$
\begin{aligned}
\rm p + p &\to \rm {}^2He^*
\\
\rm ^2He^* ...
rob♦
- 94.2k
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Resources on Solar Neutrino Physics
For a project I'm doing for an introductory Astrophysics course, I'm trying to understand the nuances of solar neutrino physics.
However, most of what is said while explaining neutrino oscillations ...
2
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1
answer
182
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Geophysical Effects of Supernova Neutrino Pulse
While neutrinos are generally totally harmless, a supernova produces enough of them at once that the neutrino flux would kill you if you could stand close enough (and not be killed by other means ...
- 2,286
3
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1
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92
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No tremendous neutrino-flux for SNIa?
Why do neutrino account for 99% of the energy release for a SN II, while it is not expected to be the case for SN Ia?
Is it because the densities are not high enough to induce inverse beta-decay?
(...
- 3,902
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1
answer
82
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Experimental evidence for the relic neutrinos
What are the experimental (indirect) evidence for the cosmic neutrino background? Where can I read more about this?
The discussion on the wikipedia page about the C$\nu$B seems to me to be more ...
- 3,902
8
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1
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516
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Is a Betelgeuse supernova able to neutralise earth's nuclear arsenal?
According to an article on newscientist.com, a neutrino beam could neutralise nuclear bombs by inducing a slow meltdown of the nuclear fuel. The neutrino generator
would need to be more than a ...
- 1,297
39
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4
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6k
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Are neutrino stars theoretically possible?
Since neutrinos
have a small mass and
are affected by gravity,
wouldn't it be theoretically possible to have such a large quantity of them so close to each other, that they would form a kind of a ...
- 775
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2
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757
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Neutrinos: how can they carry information about universe?
I know that neutrinos are particles with a very small mass and no electric charge. They infrequently interact with matter and so they can give us information about the "old" universe. But how can they ...
- 1,143
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2
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6k
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Neutrinos vs. Photons: Who wins the race across the galaxy?
Inspired by the wording of this answer, a thought occurred to me. If a photon and a neutrino were to race along a significant stretch of our actual galaxy, which would win the race?
Now, neutrinos ...
user10851