16 Novembre 2015 La ricca struttura dello spettro in energia della radiazione cosmica intorno a 1020 eV Antonio Codino Dipartimento di Fisica dell'Università.

Presentazione sul tema: "16 Novembre 2015 La ricca struttura dello spettro in energia della radiazione cosmica intorno a 1020 eV Antonio Codino Dipartimento di Fisica dell'Università."— Transcript della presentazione:

1 16 Novembre 2015 La ricca struttura dello spettro in energia della radiazione cosmica intorno a 1020 eV Antonio Codino Dipartimento di Fisica dell'Università degli Studi di Perugia e INFN. Roma, lunedì, 16 novembre 2015, ore 14:00.

2 Le caratteristiche empiriche maggiori della radiazione cosmica (2015) :
1 Lo spettro in energia dei raggi cosmici. 2 Le abbondanze relative dei vari nuclei della radiazione cosmica. 3 La durata di vita dei raggi cosmici galattici di bassa energia. Anche chiamata tempo di residenza nel disco galattico o ancora età dei raggi cosmici. 4 Uniformità delle direzioni di moto dei raggi cosmici la cosiddetta anisotropia dei raggi cosmici. 5 Le regioni del cosmo occupate dalla radiazione

3 Si definiscono alcuni termini di largo uso:
Il ciclo di vita dei raggi cosmici può suddividersi in nascita, accelerazione, propagazione e estinzione (o spegnimento). Sorgente dei raggi cosmici è un termine generico per indicare i siti d’ iniezione. I raggi cosmici provenienti dal Sole, che sono di bassa energia, al massimo circa 100 GeV (casi rari ma osservati), il sito d’ iniezione è il Sole e più precisamente le regioni sede dei brillamenti solari. Per i raggi cosmici galattici, ad esempio nella banda eV si assume nei ragionamenti che sia il mezzo interstellare indifferenziato. Ad energie inferiori a 1015 eV alcuni ritengono che particolari classi di stelle contribuiscono all’ iniezione ( ad esempio le regioni che circondano i resti di supernova).

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5 Tecnica di misura

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8 Outline Concise summary of the available data on the energy spectrum and the chemical composition measured by the Auger and TA Collaborations. Cosmic nuclei abundances versus energy (Chemical composition) from 1012 eV up to eV computed by the Theory of Constant Indices (TCI). How to infer that the cosmic radiation above 6.7 x 1020 eV is devoid of nuclei from Hydrogen to Iron and consists only of nuclei heavier than Iron. Predicted fluxes and comparison with experimental data.

9 Theoretical background based on the solution of the knee
The statement on the table is based on three separate research areas (the legs of the table) interconnected by this study. The energy interval above the ankle where the cosmic radiation consists only of ultraheavy nuclei from Zinc to the actinides Chemical composition above 2.6 x 1019 eV Energy spectra above 2.6 x 1019 eV Theoretical background based on the solution of the knee and ankle problem

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11 One example of spectrum multiplied by E2.5

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14 Cosmic-ray spectra by Haverah Park, Yakutsk, Agasa, HiRes Monocular and Auger instruments and the spectral index 2.67

15 ELI is the energy at which protons fail to be injected to the Galactic Accelerator

16 Chemical composition above
2nd leg of the table…. Chemical composition above 2.6 x 1019 eV

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20 Third independent method of measuring the chemical composition by the Auger instrument

21 In the following I take the essential outcome of the Auger experiment:
the chemical composition evolves from light to heavy in the range 3.5x10 18 eV up to 3x10 19 eV. The interpretation of the data by the TA Collaboration is slightly different from that reported by the Auger Collaboration since it has been stated : “The measured X max is consistent for being protons or light nuclei for energies eV eV. “ Astro-ph/ v1 by M. Fukushima (TA Coll.), March The same statement is reported in the comprehensive paper: arXiv : v1 R. U. Abbasi et al. (TA Coll.), 7 August 2014

22 Atmospheric depth by the TA instrument

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24 Theoretical Atmospheric Depth
Computed by the Telescope Array Collaboration Along the Years

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27 3rd leg of the table…. Theoretical background based on the solution of the knee and ankle problem. (a detailed description may be found in : Progress and Prejudice in Cosmic Ray Physics until 2006 by A. Codino )

28 trajectory simulation
Study of cosmic rays by trajectory simulation Low energies below 100 GeV 2004 2005 2006 Knee, second knee, ankle 2007 2008 2009 2010

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32 The energy interval where this principle applies is:
The principle: the spectral indices of all ions of the cosmic radiation are energy independent and have a common value of about It is called Principle of Constant Indices for the reasons described in a recent paper by A. Codino (ICRC 2015) : The Knee and Ankle Features derived from the Principle of Constant Indices and the Galactic Accelerator. The energy interval where this principle applies is: 10 GeV – 5 x 1019 eV (the iron ankle).

33 One example of spectrum multiplied by E2.5

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37 Comparison of TCI with the Traditional Theories of Cosmic Rays

38 TCI limit

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45 Features of the Galactic Accelerator
The physical process accelerating cosmic rays in the Galaxy is regarded as unknown in this presentation. The major known feature of the Galactic Accelerator is the spectral index of The maximum characteristic energy of the Galactic Accelerator is denoted here by Emax . At the end of this study it results that Emax is beyond 1020 eV.

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48 An upward deviation from a power law may signal the onset of the extragalactic component (red segment). A downward deviation signals that a subprocess of the entire galactic acceleration cycle starts to fail. Empiricarilly what happens is a downward deviation (green segment).

49 Intensity steps due to failure of particle injection to the Galactic Accelerator
2 He H CNO Ne-S 2,67 2.6x1019 eV

50 H 2,67 He CNO Ne-S 2.6x1019 eV 2,67

51 He H CNO Ne-S 2,67 2.6x1019 eV

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54 The energy point where the proton injection starts to fail
is denoted by ELI (LI for Lack of particle Injection) Measurements by Auger experiment show ELI = 2.6 x1019 eV We know from Auger data that light particles disappear before heavy nuclei; accordingly the simplest rule reflecting this fact could be : ELI = Z x ELI (H) This rule dictates that Helium (Z = 2) will disappear from the spectrum above x1019 eV The same rule determines that Carbon ( Z = 6) will disappear above x1020 eV Oxygen ( Z = 8) will disappear above 2.08x1020 eV Sulfur ( Z = 16 ) will disappear above 4.68x1020 eV Iron ( Z = 26) will disappear above 6.7x1020 eV Uranium ( Z = 92) will disappear above x1021 eV

55 ELI is the energy at which protons fail to be injected to the Galactic Accelerator

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59 The mismatch in the energy scales of TA and Auger instruments rejuvenates that existing in the published data of HiRes and AGASA.

60 An example of a rigid energy shift by 15 % (arbitrary).
But what amount is correct ?

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63 Auger data do exhibit intensity steps
ICRC 2009, Poland. ICRC 2011, China. Now (2015), the second intensity step, 9.0 x x eV, present in previous data samples, has disappeared from the Auger spectrum ( arXiv : 1503/0778v1, 26 Mar 2015). I have the impression that the large statistical error bars of the TA instrument presently impede to observe the intensity steps. .

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66 Conclusions : The energy spectrum in the range 2x1019 eV up to eV computed in this study adopts the fundamental input that cosmic rays are accelerated in the Galaxy by a power law with a universal index of 2.67 ± 0.5. This input is regarded as solid since it descends from the solution of the knee and ankle problem. The computed spectrum is not disproved by the data of TA and Auger experiments in the range 2.6 x 1020 eV eV. In the range (1-2)x 1020 eV the predicted spectrum is between the fluxes observed by Fly ‘ s Eye and AGASA experiments (too high) and Auger experiment (too low). The highest energy event (D. J. Bird et al. PRL Nov. 1993) of 3.0 (+0.36 – 0.54) x 1020 eV has never been disclaimed and has a flux consistent with the computed spectrum. According to this study the break in the spectrum discovered by HIRes in 2006 (R. U. Abbasi et al. astro-ph/ v2, 15 Feb. 2008) is caused by the failure of particle injection to the Galactic Accelerator. The hypothetical GZK effect is trivially inconsistent with the Auger data by two independent classes of observations (see A. Codino, ICRC 2013). The break

67 Spare slides

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74 the dip model of the extragalactic cosmic radiation

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77 Ion abundances at 1014 eV (High energy ion blend )
I0 =23, particles/(m2 s TeV sr) Energía = 1014 eV Iones Composición (%) Indices espectrales Intensidad (ions/m2 s sr GeV) Referencias H 36,8 2.67 ± 0.03 8,6 ± 0.32 Datos recientes de balónes He 26,1 2.64 ± 0.03 6,1 ± 0.15 CNO 13,8 2.66 ± 0.03 3,2 ± 0.06 Ne-S 10,0 2.65 ± 0.04 2,3 ± 0.07 Ca (17-20) 2,6 0,6 ± 0.05 Fe (21-26) 10,7 2.59 ± 0.04 2,5 ± 0.02

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