Questions tagged [high-energy-astrophysics]

Questions touching the field of elementary particle physics, which require high energies to be studied. Use this tag if you are asking about quarks, gluons, mesons, hadrons, leptons, etc.

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What does it mean for something to be optically thick to pair production?

I have seen several references in the high energy astrophysics literature (including the example below) which make reference to an astronomical source being "thick to pair production". What ...
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5 votes
2 answers
265 views

Do the newly-created deuterons in our Sun release any photons? In addition to a positron and an electron neutrino?

Perhaps this is a nuclear physics question, but.... When two colliding protons deep inside our Sun finally turn into a deuterium nucleus or deutron (after approximately ten octillion chances, on ...
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1 vote
0 answers
30 views

Find Periodicity in Lightcurve Using Lombscargle Periodogram(Astropy)

How to find the Nyquist factor for unevenly sampled data like here.https://github.com/jakevdp/PracticalLombScargle/blob/master/figures/LINEAR_Example.ipynb ? I have time binned for 5 mins. I mean for ...
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19 votes
2 answers
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What's the percentage of strange matter inside a star at any time?

Is there any amount of strange matter (or "top matter"?) inside stars? By strange matter I mean matter made out of flavours of quark other than up/down.
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  • 193
2 votes
0 answers
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What is the sun's maximum influence on a magnetic object?

How much magnetic repulsion could the sun's magnetic field produce on an magnetic object? Consider the object is ideal: It could be flat, to create more resistance, balanced, to stay on the opposing ...
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3 votes
1 answer
85 views

What consequences does a positive muon anomalous magnetic moment have for astronomy?

On April 7th, 2021, the muon $(g-2)$ collaboration published Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm, a result which made it to standard news, partly under headlines ...
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18 votes
2 answers
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How can astronomers pinpoint the location of the source of a neutrino?

In the popular press, in recent months, we have heard a lot about high-energy neutrinos from far outside our solar system reaching our detectors.... But I wonder... If a single neutrino from a great ...
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0 votes
0 answers
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How spaghettification is possible at the Event Horizon of a supermassive black hole?

if gravity is too strong then it will break a object apart as gravity is strong enough to break the chemical composition of object why we consider "Spaghettification" relevant in this case ?
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3 votes
1 answer
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Comparing Star Formation rate in different galaxies

I was looking for some scale to compare my result of star formation rate in order to find out whether it is moderate or high or low, but I couldn't find any scale. Is there any paper related to such ...
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1 vote
1 answer
90 views

Where can I look up assigned origins of gamma ray bursts events? (GRBs)

Gamma ray burst GRB170817A is believed to have originated from the merger of Neutron Star(NS)-Neutron Star(NS). From this article on the associated gravitational wave detection GW170817: The ...
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2 votes
2 answers
155 views

What powered the Big Bang?

According to the first law of thermodynamics, law of conservation of energy states, The total energy of an isolated system is constant; energy can be transformed from one form to another, but can be ...
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21 votes
1 answer
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Why are there no gamma-ray bursts detected in our galaxy?

I found from Wikipedia and other sites that there are no GRBs detected in the Milky Way. Can someone give a feasible reason for that? Why are there no GRBs detected in the Milky Way galaxy?
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2 votes
1 answer
322 views

Why is the number of Long Gamma Ray Burst (LGRB) event occurrences greater than the number of Short Gamma Ray Burst (SGRB) event occurrences?

I collected from NASA this histogram plotting the number of GRBs vs the duration of GRBs. Now my question is, why is the number of Long Gamma Ray Bursts (LGRBs) events occurrences greater than the ...
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-1 votes
1 answer
84 views

Higgs Field inside a White Dwarf

White dwarfs rank among the hottest things in the universe.In the early years of the life of the universe ,universe was very hot and the Higgs field was deactivated causing all the particles generated ...
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2 votes
1 answer
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Astrophysics of Supernovae - Energy over Distance?

I need this for worldbuilding, but it is a physics question. I want to be able calculate the energy over distance from a hypernova of a variable star like Eta Carinae. Understanding what energy levels ...
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1 vote
1 answer
155 views

Eddington luminosity in various plasmas

So I know that the Eddington luminosity is given by: $L_{Eddington} = 4\pi GMc/\kappa$. I want to calculate this luminosity for a plasma of purely ionized helium, as well as for an electron-...
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3 votes
1 answer
52 views

Non-thermal Sunyaev-Zel'dovich effect

Exactly what is the non-thermal Sunyaev-Zel'dovich effect? From what I understand from reading several papers by Mark Birkinshaw and Sergio Colafrancesco, I get the rough idea that the non-thermal SZ ...
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  • 43
5 votes
3 answers
832 views

Does a gravitational wave loses energy over distance?

How does a gravitational wave travel over vast distances without losing its energy? Could they go on forever as long as the Space? Thank you
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  • 163
2 votes
1 answer
273 views

What is Propeller Effect exactly?

I find the original reference seems to be here. I still do not understand the mechanism. It is necessarily occur in neutron binaries? Anyone can introduce it in detail? This paper is old.
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6 votes
3 answers
2k views

How can a singularity rotate?

So I've heard that all black holes that have been observed rotate to some degree. But if it has zero radius, how is it even possible for the black hole itself to be spinning? Or is it just all the ...
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7 votes
1 answer
3k views

Amount of energy of the Big Bang

What is the currently accepted estimated range of the amount of energy of the Big Bang event? In joules at some estimated size, so a temperature may be calculated. For context, I wonder if the ...
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9 votes
1 answer
302 views

How does the Gamma Ray Burst that occurred when 2 black holes merged compare to other GRB's?

A Gamma Ray Burst was detected 0.4 seconds after the gravitational wave event, GW150914, caused by a black hole merger, and it was in the same part of the sky. It is uncertain whether that Gamma Ray ...
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  • 742
2 votes
2 answers
366 views

Compton scattering of high energy radiation

I was reading up on compton radiation, and a question came up which I could not quite answer. Compton scattering is known to be less efficient at high energies, due to the fact that the Klein-Nishina ...
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  • 784
2 votes
3 answers
4k views

Energy needed to create a black hole vs energy needed to run the Large Hadron Collider?

I was disappointed to hear Brian Cox's flippant reply to whether or not the LHC could create a black hole big enough to swallow the earth in this video: https://www.youtube.com/watch?v=QFy87tFTZwY I'...
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2 votes
1 answer
1k views

What is the bulk Lorentz factor?

When we are talking about relativistic motions, say from a relativistic jet, what is meant by the term "bulk Lorentz factor", and the bulk speed, $\beta$?
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1 vote
1 answer
57 views

In what units to quote the thermal Blackbody temperature

Just a quick question relating to the thermal Blackbody temperature of a celestial object. In the c.g.s regime of astrophysics, is it more 'sophisticated' to quote the thermal Blackbody temperature in ...
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5 votes
1 answer
94 views

meaning of p-wave charmonia

What exactly does p-wave mean when referring to particles, like charmonia states. For example, see the following reference: http://arxiv.org/abs/hep-ph/9208254 My doubt is - p wave in scattering ...
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4 votes
1 answer
558 views

What type of energy is escaping from black-hole's poles?

Following this article, it is stated that: As a star drifts too close to a supermassive black hole, intense tidal stresses rip the star to shreds. As this happens, the shredded material will ...
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13 votes
1 answer
230 views

How will the recent appearance of a supernova, the closest in 27 years, help reduce the uncertainties in our measurements of dark energy?

A supernova has been recently spotted on M82, also known as the cigar galaxy. Being the closest to earth in 27 years and given the advances of technology this article proposes that: ...as the ...
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17 votes
3 answers
262 views

On (minuscule) dark matter production in supernovae

It is believed that dark matter is made of particles, which interact with matter only weakly and gravitationally. One common candidate for dark matter are so called WIMPs. WIMPs, specifically, are ...
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