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A.Condorelli Testing astrophysical model to interpret Auger data 2
Testing astrophysical model to interpret the Auger data PhD - - PowerPoint PPT Presentation
Testing astrophysical model to interpret the Auger data PhD - - PowerPoint PPT Presentation
Testing astrophysical model to interpret the Auger data PhD candidate: Antonio Condorelli Supervisors: Sergio Petrera, Denise Boncioli Admission to the third year, GSSI, 17th October 2019 Outline Restyling of the Combined fit; Application
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Auger spectrum
- What is the origin of the cosmic-ray features in the energy spectrum?
- Energy spectrum alone remains ambiguous concerning interpretation.
V.Verzi [PierreAugerColl.], PoS(ICRC2019)450
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Combined fit of both spectrum and composition
- A. Aab et al .,JCAP04(2017)038,arXiv:1612.07155v3
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Update of the combined fit
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Update of the combined fit
Working principle of the combined fit
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Update of the combined fit
Working principle of the fraction fit
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Working principle of the fraction fit P r e s e n t e d a t I C R C 2 1 9 !
Update of the combined fit
A.Yushkov [PierreAugerColl.], PoS(ICRC2019)482
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17 17.5 18 18.5 19 19.5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
H EPOS-LHC - Gumbel
17 17.5 18 18.5 19 19.5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
He
17 17.5 18 18.5 19 19.5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
N
17 17.5 18 18.5 19 19.5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Fe
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Results of fraction fit
500 600 700 800 900 1000 ]- 2
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Testing source effect mechanism
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Testing source effect mechanism
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Auger measurements
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What is the ankle?
If we assume only proton spectrum—> feature of the propagation; Transition point between galactic and extragalactic cosmic rays; Two extragalactic components; Source mechanism;
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Testing a model
Consider a system in which the accelerator (also referred to as the source) is embedded in an environment in which the cosmic rays are confined by magnetic fields while interacting with the ambient radiation field. The lower the energy, the more time the nuclei have to interact before escaping, leading to a hardening of the spectrum and lightening of the composition of nuclei escaping the region surrounding the source.
Origin of the ankle in the ultrahigh energy cosmic ray spectrum and of the extragalactic protons below it, M.Unger, G. Farrar, L. Anchordoqui, arXiv:1505.02153v2
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Interaction time easy to compute; Propagation and production of secondary particles; Implementation of a generic photon field; A single code for propagation inside and outside the source;
SimProp
SimProp v2r4: Monte Carlo simulation code for UHECR propagation, R.Aloisio, D.Boncioli, A.Di Matteo, A.F. Grillo, S.Petrera, F.Salamida, arXiv:1705.03729 .
What ? Why?
MonteCarlo code for propagation of particle through the Universe; Generation of a primary (proton or nucleus) and its propagation from the source to the observer; Taking into account all possible energy losses;
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Interaction and escape time
The shape of the spectrum of the target photons is needed. The interaction time is given by the double integral on the cross sections and on the photon field; The escaping time is just a power law on rigidity.
Photomeson Photodisintegration Total
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H He N Si Fe
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17.5 18 18.5 19 19.5 20 20.5 log10(E)[eV]
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Ejected Spectra
18 Origin of the ankle in the ultrahigh energy cosmic ray spectrum and of the extragalactic protons below it, M.Unger, G. Farrar, L. Anchordoqui, arXiv:1505.02153v2
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Neutrino spectrum from the source
8 10 12 14 16 18 log10(E)[eV]
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10 dN/dlogE [a.u.]
Legenda Standard configuration High Luminosity
Neutrinos
Increasing luminosity by a factor 10 Decreasing temperature by a factor 10
8 10 12 14 16 18 log10(E)[eV]
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Legenda Standard configuration low T
Neutrinos
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Application of source mechanism to SBGs
Cosmic ray transport and radiative processes in nuclei of starburst galaxies, E.Peretti, P .Blasi, F.Aharonian, G.Morlino. arXiv:1812.01996v2
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Summary and future perspectives
Organizing combined fit code according to a logic structure and applications; Fit using two components. A single code for propagation inside and outside the source; How the neutrino flux (produced in the source) changes according to the source parameters —> Additional observables with respect to cosmogenic neutrinos. Studying of parameter space for real sources; Studying of the diffusion process inside the source; Development of simplified analytical approach; Fit at the source. Tools Source mechanism Interpretation
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Summary and future perspectives
Organizing combined fit code according to a logic structure and applications; Fit using two components. A single code for propagation inside and outside the source; How the neutrino flux (produced in the source) changes according to the source parameters —> Additional observables with respect to cosmogenic neutrinos. Studying of parameter space for real sources; Studying of the diffusion process inside the source; Development of simplified analytical approach; Fit at the source. Tools Source mechanism Interpretation combined fit
Source mechanism
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b a c k
- u
p s l i d e s
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Assumptions
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7 −
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4 −
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3 −
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10 Energy (eV) 2 4 6 8 10 12 14 16
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dN/dE [ev
Comparison of photon spectra
17.5 18 18.5 19 19.5 20 1 10
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Time scale vs Energy
Changing the temperature
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Changing the luminosity
0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 Energy (eV) 20 40 60 80 100 120 140 160
910 × ]
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dN/dE [ev
Comparison of photon spectra
17.5 18 18.5 19 19.5 20
1 −
10 1 10
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Parameters in the fit
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Fit the Auger Data
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Injection
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Advection and diffusion time
➤ Advection time: just the ratio between the size of the source R and the
velocity of the wind. v = 500 Km/s; R = 300 pc
➤ Diffusion time is given by
Where:
➤ d = 5/3; ➤ L0 = 1 pc; ➤ R = 300 pc; ➤ (ΔB/B) = 1 ➤ if (RL > L0 ) we multiply the diffusion coefficient D0 by a factor (RL /L0)2 ➤ If (tdiff < R/c) tdiff = R/c