Propagation of Ultra–High‐Energy Cosmic Rays above 10<sup>19</sup>eV in a Structured Extragalactic Magnetic Field and Galactic Magnetic Field

We investigate the possibility that observations of ultra-high-energy cosmic-rays (UHECRs) in the near future may be able to unveil their local source distribution. We simulate the arrival distribution of UHE protons taking account of their propagation process in intergalactic magnetic field (IGMF) associated with the local structure actually observed around the Milky Way and investigate the similarity of the spatial patterns between the arrival distribution and the source distribution. We find that UHE protons above 1019.8 eV are the best indicators for unravelling the source distribution within 100 Mpc, and the detection of about 500 events on the whole sky would realize the purpose for plausible IGMF strength and source number density. We also discuss the deflection of the trajectories of UHE protons by the Galactic magnetic field (GMF). In favored GMF models, the deflection angles are consistent with the angular scale of the positional correlation reported by the Pierre Auger Observatory except in the direction of Galactic center. Thus, UHECR observatories in the northern hemisphere is preferred.

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“…which can well reproduce the data of Akeno Giant Air Shower Array, [11][12][13][14] such number is about 500 for protons above 10…”

Section: Resultssupporting

confidence: 71%

“…The strength of our IGMF model developed in our previous study 11) is normalized at the center of Virgo cluster as B. In this structured IGMF model, 95% of the volume has no magnetic field reflecting the structure of the local universe.…”

Section: Methodsmentioning

confidence: 99%

Towards Unravelling the Structural Distribution of Ultra-High-Energy Cosmic Ray Sources

Takami

Sato

2009

J. Phys. Soc. Jpn.

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“…Mika Kagaya Galactic magnetic field [12]. If heavy nucleus are accelerated, the deflection angle is possible to be larger than the case of protons.…”

Section: Constraints On Acceleration Of Uhecrs In Fermi Gamma-ray Soumentioning

confidence: 99%

Constraints on acceleration of ultra high-energy cosmic rays in Fermi gamma-ray sources

Kagaya¹,

Yoshida²

2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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We investigate the candidates of accelerator of ultra-high-energy cosmic rays (UHECRs) using the multi-wavelength spectral energy distributions, and discuss about the ability to accelerate UHECRs and constrain their physical conditions (acceleration site and size). The current experimental statistics of UHECRs is not sufficient for identification of the sources, although a spatial correlation between the arrival directions of UHECRs and nearby active galactic nuclei (AGNs) has been discussed using the data of the Pierre Auger Observatory and the Telescope Array. Some authors have discussed about the acceleration of UHECRs using various methods. Among them, Pe'er & Loeb (2012) derived constraints on the ability of AGNs to produce UHECRs by using observational quantities which are synchrotron peak luminosity and the peak flux ratio of inverse Compton scattering to synchrotron emission. For adopting this method, we need data of gammaray observation to determine the peak flux for high-energy region due to inverse Compton scattering. Thus, we focused on the Fermi Large Area Telescope gamma-ray sources. We investigated a spatial correlation between AGNs and the arrival directions of UHECRs, and we selected six AGNs as candidates of accelerator of UHECRs. We analyzed their spectral energy distributions by using multi-wavelength archival observational data. By introducing the constraints of Pe'er & Loeb (2012), we evaluate the physical conditions in the acceleration regions of these six AGNs and discuss whether they can accelerate to UHECRs. From the analysis, we found that three AGNs have ability to accelerate UHE protons to UHECRs in the AGN cores. Furthermore, we constrained the minimum size of the acceleration region for each source when UHE particles are accelerated in the AGN lobes. If UHE protons are accelerated, a few kpc-100 kpc are required as the minimum acceleration size. In the case of acceleration of heavy nucleus, the heavy particles can be accelerated in the AGN lobes if the size is larger than a few kpc. In this paper, we show that we achieved to establish a test method for individual candidate sources of acceleration of UHECRs.

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“…These models are almost the same as those in our previous work. More detailed explanations are written in Takami et al (2006). These models are constructed from Infrared Astronomical Satellite Point Source Catalogue Redshift Survey (IRAS PSCz) catalog of galaxies (Saunders et al 2000).…”

Section: Source Distribution and Magnetic Fieldmentioning

confidence: 99%

Towards unravelling the structural distribution of ultra-high-energy cosmic ray sources

Takami¹,

Sato²,

Kodama³

et al. 2008

AIP Conference Proceedings

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We investigate the possibility that near future observations of ultra-high-energy cosmic rays (UHECRs) can unveil their local source distribution, which reflects the observed local structures if their origins are astrophysical objects. In order to discuss this possibility, we calculate the arrival distribution of UHE protons taking into account their propagation process in intergalactic space i.e. energy losses and deflections by extragalactic magnetic field (EGMF). For a realistic simulation, we construct and adopt a model of a structured EGMF and UHECR source distribution, which reproduce the local structures actually observed around the Milky Way. The arrival distribution is compared statistically to their source distribution using correlation coefficient. We specially find that UHECRs above 1019.8 eV are best indicators to decipher their source distribution within 100 Mpc, and detection of about 500 events on all the sky allows us to unveil the local structure of UHE universe for plausible EGMF strength and the source number density. This number of events can be detected by five years observation by Pierre Auger Observatory.

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Propagation of Ultra–High‐Energy Cosmic Rays above 10¹⁹eV in a Structured Extragalactic Magnetic Field and Galactic Magnetic Field

Cited by 43 publications

References 41 publications

Towards Unravelling the Structural Distribution of Ultra-High-Energy Cosmic Ray Sources

Towards Unravelling the Structural Distribution of Ultra-High-Energy Cosmic Ray Sources

Constraints on acceleration of ultra high-energy cosmic rays in Fermi gamma-ray sources

Towards unravelling the structural distribution of ultra-high-energy cosmic ray sources

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Propagation of Ultra–High‐Energy Cosmic Rays above 1019eV in a Structured Extragalactic Magnetic Field and Galactic Magnetic Field

Cited by 43 publications

References 41 publications

Towards Unravelling the Structural Distribution of Ultra-High-Energy Cosmic Ray Sources

Towards Unravelling the Structural Distribution of Ultra-High-Energy Cosmic Ray Sources

Constraints on acceleration of ultra high-energy cosmic rays in Fermi gamma-ray sources

Towards unravelling the structural distribution of ultra-high-energy cosmic ray sources

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Product

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Propagation of Ultra–High‐Energy Cosmic Rays above 10¹⁹eV in a Structured Extragalactic Magnetic Field and Galactic Magnetic Field