Questions¶
Gamma ray source.¶
These VHE photons have energies between 100 GeV to 10 TeV and are produces by extraordinary astrophysical process or by forces beyond the SM(It’s such a bald hypothesis).
From source to detector, ignore (IGBL) the medium between. a part of light will directly arrive at earth, and probed by detector, like sun emits light and the sky is bright. Since there exists IGBL, part of the light can make to arrive at earth.
Some of them will travel to earth without scattering which will give you access to intrinsic spectrum of the source so what is producing at the source. some of them are going to scatter EBL that they encounter on the way to earth.
Why did EBL catch our attention?¶
It is one of the most fundamental observational quantities in cosmology.
See also
As we send spacecraft and astronauts further and further from home, we must understand this space environment just as early seafarers needed to understand the ocean.
What exactly is EBL spectrum?¶
The Correlation length of EGMF.¶
When the primary VHE gamma photon interact with EBL, the length it went through. Before the pair being deflected by IGMF, the pairs won’t go along the direction primary photon.
Physicists used the relic of Gamma ray from blazar to put constraints on physical parameter of IGM.
They compare their analytical result with Monte Carlo simulation which represents what indeed happens in the world.
Magneticgensis refers to The mechanism to produce magnetic field. When the magnetic start to present.
- Before the star formation.
- While the star formation.
We care about the beginning time since what.
How to set lower limit and upper limit of EGMF?¶
According to data from Fermi and HESS etc.
Helicity of magnetic field.¶
Time delay of the two photons undergo different situation.¶
If the VHE pairs didn’t scatter with photons of CMB and travel to earth, how do we discriminate it with VHE photons. Will it initiate EM cascade? If we are not able to differentiate them, what reason do we have to ignore the noise.
“High-energy gamma rays can be produced either by accelerated electrons or protons. The observation of a neutrino, which is a hallmark of proton interactions, is the first definitive evidence of proton acceleration by black holes.”
Think over the CMB and Big Bang¶
From Quora:
The origination of the big bang may have been point-like, but that says nothing about there being a “direction” of the big bang. Every point in space come from the big bang point of the origin.
The CMB was formed when the universe cooled to a point that free electrons and protons could combine to form neutral hydrogen. This allowed light to travel for great distances without being scattered. This happened everywhere in the observable universe at roughly the same time, which explain why we see the CMB in every direction. We are continually receiving photons that begin to stream uninterrupted from points in space that are increasingly farther away.
If every point in a finitely boundless space begin to expand outwards it would result in the same scenario.
What is large scale structure?¶
Primordial magnetic fields in the voids of LSS.
How well do I know the whole facts ?¶
I am supposed to know the actual process of doing computation in the astrophysical area, I come out with none about what exactly I need to do, the deflected angle between primordial and observed light. the time delation, according to the
Some one said don’t place the cart before the horse, and don’t place the answer before the question, I think about the problems, I don’t know exactly the logics behind the big problems. I apply the possible approach to find out something.
By making your assumptions as well as your hypotheses explicit you increase the clarity of your approach and the chance for learning.
Energy Scale [1]¶
For a proton at 7 TeV, this is 99.9999991% times the speed of light
Now, keep in mind this is for EACH proton in two BEAMS, each one of them having 7 TeV, travelling through a superconductor cooled by helium, and then colliding for a sum of 14 TeV.
Each proton beam contains 2,808 ‘bunches’ of protons, and each ‘bunch’ contains \(1.15 \times 10^{11}\) protons, so each beam then consists of 362 MJ (Megajoules).
This gives a total kinetic energy of 724 MJ just in the beams alone: about 7 times the kinetic energy as landing a 55 tonne aircraft at typical landing speed according to the [Joules Orders of Magnitude] wiki page, or with that \(59~\mathrm{ m/s}\) landing speed, 218.9 tonnes, so about a safely loaded Airbus A330-200 ([maximum takeoff weight of 242 tonnes])
Add to that the energy required to keep the ring supercooled enough so it remains superconductive, accelerate the beam in the first place, keep accelerating it so it doesn’t lose velocity, light and heat and power the facility.
See also
At peak consumption, usually from May to mid-December, CERN uses about 200 megawatts of power, which is about a third of the amount of energy used to feed the nearby city of Geneva in Switzerland. The Large Hadron Collider (LHC) runs during this period of the year, using the power to accelerate protons to nearly the speed of light. CERN’s power consumption falls to about 80 megawatts during the winter months.
To get a feel about these energy unit, compare specific energy scale to the energy of usual things. Like may be the mosquito’s typical energy, a running person’s typical energy,
Footnotes
| [1] | https://physics.stackexchange.com/questions/320440/why-dont-we-notice-higher-energy-photons-in-practice?s=3|15.7878 |