Update on the large-scale cosmic-ray anisotropy search at the highest energies by the Telescope Array Experiment

Fujii, Toshihiro

doi:10.22323/1.395.0291

Cited by 3 publications

(1 citation statement)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The TA collaboration searched, using 12 years of data, but did not see a significant dipole structure [78]. This result was still consistent with Auger, due to the lower event statistics.…”

Section: Pos(icrc2021)043supporting

confidence: 54%

Cosmic Ray Indirect Rapporteur Report (37th ICRC )

Abu‐Zayyad¹

2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

View full text Add to dashboard Cite

This report summarizes the physics results presented as part of the cosmic-ray indirect (CRI) session of the 37 th ICRC conference. Updated measurements on cosmic-ray energy spectrum, mass composition, and arrival direction distributions were presented by several collaborations, spanning the energy range of a few TeV up to the highest observed energies. We select some of the results which were highlighted by the respective discussion leaders or which presented new results at this conference. Results on atmospheric phenomena, including TGFs and thunderstorms are also presented. We see a few interesting trends in the presented data. Among these are, the increased use of IACT's to study cosmic-rays among experiments primarily intended for gamma-ray measurements. Another, is the continued development of radio detection of air showers. Multi-component detectors are becoming the preferred detection mode, as the knowledge of how to integrate the different information about an air shower collected by the different detector components improves. The main physics questions about the origins of cosmic rays, both galactic and extra-galactic, remain open. Increased statistics and improved analyses allow for refining and better constraining theoretical models, but no definitive answers can be claimed thus far. Looking forward, the field is moving at a rapid pace; Several detectors upgrades are underway, data is continually coming in and analyzed, old data being made public for a wider audience and a new generation of scientists to examine, with new tools and approaches that will hopefully result in new insights to help solve the open questions on cosmic-rays.

show abstract

“…The TA collaboration searched, using 12 years of data, but did not see a significant dipole structure [78]. This result was still consistent with Auger, due to the lower event statistics.…”

Section: Pos(icrc2021)043supporting

confidence: 54%

Cosmic Ray Indirect Rapporteur Report (37th ICRC )

Abu‐Zayyad¹

2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

View full text Add to dashboard Cite

show abstract

What can be learnt from UHECR anisotropies observations

Allard

Aublin

Baret

et al. 2022

A&A

View full text Add to dashboard Cite

Context. In recent years, evidence for an anisotropic distribution of ultra-high-energy cosmic rays (UHECRs) has been claimed, notably a dipole modulation in right ascension has been reported by the Auger collaboration above the 5σ significance threshold. Aims. We investigate the implications of the current data regarding large-scale anisotropies, including higher order multipoles, and we examine to what extent they can be used to shed some light on the origin of UHECRs and constrain the astrophysical and/or physical parameters of the source scenarios. We investigate the possibility of observing an associated anisotropy of the UHECR composition and discuss the potential benefit of a good determination of the composition and of the separation of the different nuclear components. We also discuss the interest and relevance of observing the UHECR sky with larger exposure future observatories. Methods. We simulated realistic UHECR sky maps for a wide range of astrophysical scenarios satisfying the current observational constraints, taking into account the energy losses and the photo-dissociation of the UHE protons and nuclei, as well as their deflexions by intervening magnetic fields. We investigated scenarios in which the UHECR source distribution follows that of the galaxies in the Universe (with possible biases), varying the UHECR source composition and spectrum, as well as the source density and the magnetic field models. For each of them, we simulated 300 realizations of independent datasets corresponding to various assumptions for the statistics and sky coverage, and we applied similar analyses as those used by the Auger collaboration for the search of large-scale anisotropies. Results. We find the following. First, reproducing the amplitude of the first-order (dipole) anisotropy observed in the Auger data, as well as its evolution as a function of energy, is relatively easy within our general assumptions. Second, this general agreement can be obtained with different sets of assumptions on the astrophysical and physical parameters, and thus it cannot be used, at the present stage, to derive strong constraints on the UHECR source scenarios or draw model-independent constraints on the various parameters individually. Third, the actual direction of the dipole modulation reconstructed from the Auger data, in the energy bin where the signal is most significant, appears highly unnatural in essentially all scenarios investigated, and this calls for their main assumptions to be reconsidered, either regarding the source distribution itself or the assumed magnetic field configuration, especially in the Galaxy. Fourth, the energy evolution of the reconstructed dipole direction contains potentially important information, which may become constraining for specific source models when larger statistics is collected. Fifth, for such high-statistics datasets, most of our investigated scenarios predict a significant quadrupolar modulation, especially if the light component of UHECRs can be extracted from the all-particle dataset. Sixth, except for protons, the energy range in which the GZK horizon strongly reduces is a key target for anisotropy searches for each given nuclear species. Seventh, although a difference in the average composition of the UHECRs in regions having a different count rate is naturally expected in our models, it is unlikely that the composition anisotropy recently reported by Auger can be explained by this effect, unless the reported amplitude is a strong positive statistical fluctuation of an intrinsically weaker signal.

show abstract

A cosmic-ray database update: CRDB v4.1

Maurin,

Ahlers,

Dembinski

et al. 2023

Eur. Phys. J. C

View full text Add to dashboard Cite

The cosmic-ray database, , has been gathering cosmic-ray data for the community since 2013. We present a new release, , providing many new quantities and data sets, with several improvements made on the code and web interface, and with new visualisation tools. relies on the MySQL database management system, and libraries for queries and sorting, and PHP web pages and AJAX protocol for displays. A REST interface enables user queries from command line or scripts. A new (pip-installable) CRDB python library is developed and extensive jupyter notebook examples are provided. This release contains cosmic-ray dipole anisotropy data, high-energy $$\bar{p}/p$$ p ¯ / p upper limits, some unpublished LEE and AESOP lepton time series, many more ultra-high energy data, and a few missing old data sets. It also includes high-precision data from the last three years, in particular the hundreds of thousands AMS-02 and PAMELA data time series (time-dependent plots are now enabled). All these data are shown in a gallery of plots, which can be easily reproduced from the public notebook examples. contains 316,126 data points from 504 publications, in 4111 sub-experiments from 131 experiments.

show abstract

Update on the large-scale cosmic-ray anisotropy search at the highest energies by the Telescope Array Experiment

Cited by 3 publications

References 15 publications

Cosmic Ray Indirect Rapporteur Report (37th ICRC )

Cosmic Ray Indirect Rapporteur Report (37th ICRC )

What can be learnt from UHECR anisotropies observations

A cosmic-ray database update: CRDB v4.1

Contact Info

Product

Resources

About