The Highest Energy Particles in Nature – the Past, the Present and the Future
Alan Watson
University of Leeds
Since the earliest days cosmic-ray physicists have been studying the highest-energy particles in Nature. A basic understanding of the development of electromagnetic cascades led to the first targeted searches for air showers and, soon after the discovery of charged and neutral pions,...
Telescope Array (TA) is measuring cosmic rays of energies from PeV to 100 EeV and higher in the Northern hemisphere. TA has two parts: main TA and the TA low energy extension (TALE). Main TA is a hybrid detector that consists of 507 plastic scintillation counters on a 1200m - spaced square grid that are overlooked by three fluorescence detector stations. TALE is also a hybrid detector and it...
The energy spectrum of high-energy cosmic rays measured using the Pierre Auger Observatory is presented. The measurements extend over three orders of magnitude in energy from 3 x 10^17 eV up to the very end of the spectrum and they benefit of the almost calorimetric estimation of the shower energies performed with the fluorescence telescopes. The huge amount of data collected with the surface...
The energy spectrum of ultra-high energy cosmic rays is the most emblematic observable for describing these particles. Beyond a few tens of EeV, the Pierre Auger Observatory and the Telescope Array, currently being exploited, provide the largest exposures ever accumulated in the Northern and the Southern hemispheres to measure independently a suppression of the intensity, in a complementary...
In this talk I'll present minimal model, which explain UHECR spectrum and composition and at the same time explain IceCube astrophysical neutrino signal (M.Kachelriess et al, ``Minimal model for extragalactic cosmic rays and neutrinos,'' Phys.Rev.D 96}, 083006 (2017) Also I'll discuss galactic-extragalactic transition in context of this model.
An array of non-imaging Cherenkov light collectors has recently been installed at the Telescope Array Middle Drum site, in the field-of-view of the TALE FD telescopes. This allows for imaging/non-imaging Cherenkov hybrid observations of air showers in the energy range just above 1 PeV. The performance of the array and the first analyses using hybrid measurements will be presented.
We present a parametrisation of the cosmic-ray flux and its mass composition over an energy range from 1 GeV to $10^{11}$ GeV, which can be used for theoretical calculations. The parametrisation provides a summary of the experimental state-of-the-art for individual elements from proton to nickel. We seamlessly combine measurements of the flux of individual elements from high-precision...
Ultra-high energy cosmic rays pose an extreme challenge to theories of particle acceleration. We discuss the reasons why diffusive acceleration by shocks is a leading contender. A crucial aspect of shock acceleration is that cosmic rays must be efficiently scattered by magnetic field. This requires magnetic field amplification on scales comparable with the cosmic ray Larmor radius, which in...
We present measurements from the Pierre Auger Observatory related to
mass composition of ultra-high energy cosmic rays.
Using the fluorescence telescopes of the Observatory we determine the
distribution of shower maxima (Xmax) from 10^17.2 to 10^19.6 eV and
derive estimates of the mean and variance of the average logarithmic
mass of cosmic rays. The fraction of p, He, N and Fe nuclei as...
Telescope Array (TA) has recently published results of nearly nine years of $X_{\mathrm{max}}$ observations providing it's highest statistics measurement of UHECR mass composition to date for energies exceeding $10^{18.2}$ eV. This analysis measured agreement of observed data with results expected for four different single elements. Instead of relying only on the first and second moments of...
At the Pierre Auger Observatory and the Telescope Array (TA) experiment the measurements of depths of maximum of air-shower profiles, $X_{\rm max}$, are performed using direct observations of the longitudinal development of showers with the help of the fluorescence telescopes. Though the same detection technique is used by both experiments, the straightforward comparison of the characteristics...
The TUS experiment is designed to investigate the ultra high energy cosmic rays (UHECR) at energy ∼100 EeV from the space orbit by the UV radiation measurement of extensive air showers (EAS). It is the first orbital telescope aimed for such measurements and is taking data since April 28, 2016. TUS detector consists of a modular Fresnel mirror and a photo receiver matrix with a field of view...
Nowadays, ultra high energy cosmic rays (UHECR) are subject to intense research of great interest. The existence of such rays with an energy above $10^{20}$ eV is contradicted by the limit GZK due to photo-pion production, or by nuclei photo-disintegration, in the interaction of UHECR with the cosmic microwave background.
In this work, detailed simulations of extensive air showers have been...
High speed photon detectors are one of the most important tools for observations of high energy cosmic rays. As technology of photon detectors and its read-out electronics improved rapidly, it became possible to observe cosmic rays with time resolution better than one nano-second. To utilize such devices effectively, calibration using a short-pulse light source is mandatory. We have developed...
The IceCube Collaboration recently announced the detection of a high-energy astrophysical neutrino consistent with arriving from the direction of the blazar TXS 0506+056 during an energetic gamma-ray flare. In light of this finding, we consider the implications for neutrino emission from blazar flares in general. We discuss the likely total contribution of blazar flares to the diffuse neutrino...
Over the years, significant efforts have been devoted to the understanding of the radio emission of extensive air shower (EAS) in the range [20-80] MHz but, despite some studies led until the nineties, the [1-10] MHz band has remained unused for nearly 30 years. At that time it has been measured by some pioneering experiments but also suggested by theoretical calculations that EAS could...
We are developing a standard light source with UV-LED of calibration device for fluorescence detector (FD). This device is called Opt-copter. The standard light source is mounted on the UAV, and it can stay at an arbitrary position within the FOD of the FD. The GPS for surveying is highly accurate (~10 cm) and measures the position of the light source synchronously with the light emission....
The Auger@TA project is a combined effort involving members of both the Pierre Auger Observatory and the Telescope Array experiment (TA) to cross-calibrate detectors and compare results on air showers detected at one location. We have recently reported results from Phase I of the project, during which we collected and presented data from two Auger water-Cherenkov surface-detector stations...
We report the ultra-high energy (> 1EeV) photon flux limits based on the analysis of the 9 years data from the Telescope Array Surface detector. The multivariate classifier is built upon 16 reconstructed parameters of the extensive air shower. These parameters are related to the curvature and the width of the shower front, the steepness of the lateral distribution function and the timing...
ast year, LIGO-VIRGO collaborations reported detection of the first neutron star merger event, GW170817, which accompanied with observations of electromagnetic counterparts from radio to gamma rays. High-energy gamma rays and neutrinos were not observed. However, the mergers of neutron stars are expected to produce these high-energy particles. Relativistic jets are expected to be launched when...
In the context of the recent multi-messenger observation of neutron-star merger GW170817, we examine whether such objects could be sources of ultra-high energy astroparticles. At first order, the energetics and the population number is promising to envisage the production of a copious amount of high-energy particles, during the first minutes to weeks from the merger. In addition, the strong...
Evidence of supergalactic structure of multiplets has been found for ultra-high energy cosmic rays (UHECR) with energies above 10$^{19}$ eV using 7 years of data from the Telescope Array (TA) surface detector. The tested hypothesis is that UHECR sources, and intervening magnetic fields, may be correlated with the supergalactic plane, as it is a fit to the average matter density within the GZK...
Magnetic fields are an important agent for cosmic rays to transport. The observed all-sky Faraday rotation distribution implies that the magnetic fields in the Galactic halo have a toroidial structure, but the radius range and scale height as well as the strength of the toroidial fields are totally unknown. In the Galactic disk, the magnetic fields probably follow the spiral structure with a...
The origin of ultra-high energy cosmic rays (UHECRs) is an open question, but radio galaxies offer one of the best candidate acceleration sites. Acceleration at the termination shocks of relativistic jets is problematic because relativistic shocks are poor accelerators to high energy. Using hydrodynamic simulations and general physical arguments, I will show that shocks with non- or mildly...
Arrays of imaging atmospheric Cherenkov telescopes (IACTs), such as VERITAS and the future CTA observatory, are designed to detect particles of astrophysical origin. IACTs are nominally sensitive to gamma rays and cosmic rays at energies between tens of GeV and hundreds of TeV. As such, they can be used as both direct and indirect probes of particle acceleration to very high energies.
Recent...
The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a proposed large-area, next-generation experiment for the detection of ultra-high energy cosmic rays via the atmospheric fluorescence technique. The telescope’s large field-of-view (30°x30°) is imaged by four 200 mm photomultiplier-tubes at the focal plane of a segmented spherical mirror of 1.6 m diameter. Two prototypes are...
The TA experiment has three FD stations these containing 38 FDs.
In addition, 16 FD was newly added by TAx4 and TALE.
In order to reconstruct FD observation data to air shower information, it is necessary to calibrate the influence of aerosol attenuation. CLF measures atmospheric transparency of TA site.
The arrival directions of cosmic rays detected by the Pierre Auger Observatory (Auger) with energies above 39 EeV were recently reported to correlate with the positions of 23 nearby starburst galaxies (SBGs): in their best-fit model, 9.7% of the cosmic-ray flux originates from these objects and undergoes angular diffusion on a 12.9° scale. On the other hand, some of the SBGs on their list,...
Telescope Array constructed in Utah USA is a largest air shower observatory in the northern hemisphere aiming at clarifying the origin of UHECRs. In order for better understandings of the air shower phenomenon we report a study on the distribution of arriving signals measured with FADC of the TA Surface detector we use 10 years TA SD data to examine which include delay time to shower front...
The IceCube Neutrino Observatory at the geographic South Pole, with its surface array IceTop, detects three different components of extensive air showers: the total signal at the surface, low energy muons in the periphery of the showers, and high energy muons in the deep array of IceCube. These three components allow for a variety of cosmic ray measurements including the energy spectrum and...
The KASCADE-Grande experiment has significantly contributed to the current knowledge about the energy spectrum and composition of cosmic rays for energies between the knee and the ankle. Meanwhile, post-LHC versions of the hadronic interaction models are available and used to interpret the entire data set of KASCADE-Grande. In addition, a new, combined analysis of both arrays, KASCADE and...
Additionally to the all-particle cosmic ray (CR) spectrum, data on the
primary composition and anisotropy have become available from the knee region up to few $\times 10^{19}$ eV. These data point to an early Galactic-extragalactic transition and the presence of Peter's cycle, i.e. a rigidity-dependent maximal energy. Theoretical models have to explain therefore the ankle as a feature in the...
Knowledge about the processes dictating UHECR
losses during their propagation in extragalactic space
allows the secondary species to be used to probe the source
location. In this talk I will cover the state of our knowledge on
these processes, and gives examples about properties of the
sources that may be inferred from the observed secondary
species at Earth. Some suggestion will also be...
I will review the status of measurements and modelling of Galactic and intergalactic magnetic fields in the context of multi-messenger astrophysics and in particular of UHECR observations.
I will review our knowledge about the properties and the origin of the extragalactic gamma-ray background above 100 MeV. Since the universe is transparent to MeV and GeV gamma rays up to very high redshifts, the extragalactic gamma-ray background contains the imprint of all gamma-ray emission from the beginning of star formation until the present day. Its properties have important implications...
The Telescope Array (TA) is an international experiment studying ultra-high energy cosmic rays.
TA uses fluorescence detection technology to observe cosmic rays, and in order to estimate the flux of cosmic rays with the observation of the fluorescence detector (FD), it is necessary to estimate the condition of FD observation area correctly.
Because the cloud has a great influence on the Field...
Experimental observations of Galactic and extragalactic cosmic rays, neutrinos and gamma rays in the last decade challenge the theoretical description of both the sources and the transport of these particles. The latest version of the publicly available simulation framework CRPropa 3.2 is a Monte-Carlo based software package capable of providing consistent solutions of the cosmic-ray origin...
We present a novel approach to search for origins of ultra-high energy cosmic rays. In a simultaneous fit to all observed cosmic rays we use the galactic magnetic field as a mass spectrometer and adapt the nuclear charges such that their extragalactic arrival directions are concentrated in as few directions as possible. During the fit the nuclear charges are constraint by the individual...
EUSO-TA is a cosmic ray detector developed by the JEM-EUSO Collaboration (Joint Experiment Missions for Extreme Universe Space Observatory), observing during nighttime the fluorescence light emitted through the path of extensive air showers in the atmosphere. It is installed at the Telescope Array site in Utah, USA, in front of the fluorescence detector station in Black Rock Mesa, as...
Telescope Array (TA) is a large cosmic ray detector in the Northern hemisphere that measures cosmic rays of energies from PeV to 100 EeV and higher. Main TA consists of a surface detector (SD) of 507 plastic scintillation counters of 1200 m separation on a square grid that is overlooked by three fluorescence detector stations. We present the cosmic ray energy spectrum measured by the TA SD...
The Fluorescence Detector (FD) at the Pierre Auger Observatory has triggered on numerous elves since the first observation in 2005, and it has potential for simultaneous Terrestrial Gamma ray Flashes (TGF) detection. In addition, the Surface Detector (SD) observed peculiar events with radially expanding footprints, which are correlated with lightning strikes reconstructed by the World Wide...
The Pierre Auger Observatory is currently upgrading its surface detector array by placing a 3.84 square meter scintillator on top of each of the existing 1660 water-Cherenkov detectors. The differing responses of the two detectors allow for the disentanglement of the muonic and electromagnetic components of extensive air showers, which ultimately facilitates reconstruction of the mass...
The Hellenic Open University (HOU) Cosmic Ray Telescope (ASTRONEU) comprises 9 charged particle detectors and 3 RF antennas arranged in three autonomous stations operating at the University Campus of HOU in the city of Patra. In this work, we extend the analysis of very high energy showers that are detected by more than one station and in coincidence with the RF antennas of the Telescope. We...
The study of correlations between observations of fundamentally different nature from extreme cosmic sources promises extraordinary physical insights into the Universe. With the Pierre Auger Observatory we can significantly contribute to multi-messenger astrophysics by searching for ultra-high energy particles, particularly neutrinos and photons which, being electrically neutral, point back to...
Finally a hundred years after the discovery of cosmic-rays, a blazar has been identified as a source (at ~3 sigma level) of high-energy neutrinos and cosmic-rays thanks to the real-time multimessenger observation lead by the cubic-kilometer IceCube neutrino observatory. In this talk, details of the spatial-timing correlation analysis of the ~290 TeV neutrino event with Fermi light curves will...
The ANTARES detector is currently the largest undersea neutrino telescope. Located in the Mediterranean Sea at a depth of 2.5 km, 40 km off the Southern coast of France, it has been looking for cosmic neutrinos for more than 10 years. High-energy cosmic neutrino production is strongly linked with cosmic ray production. The latest results from IceCube represent a step forward towards the...
We present the results of three searches for correlations between UHECR events measured by the Pierre Auger Observatory and Telescope Array and high energy neutrino candidate events from IceCube and ANTARES. A cross-correlation analysis is performed, where the angular separation between the arrival directions of UHECRs and neutrinos is scanned. The same events are also exploited in a separate...
ANITA was designed as a discovery experiment for ultra-high energy (UHE) neutrinos using the radio Askaryan detection technique, launching from McMurdo Station in Antarctica under NASA’s long duration balloon program and observing 1.5 million square kilometers of ice at once from an altitude of 40 km. Over ANITA’s four flights we set the best constraints on UHE neutrino fluxes above 10^19 eV,...
When UHECRs propagate through the universe, cosmogenic neutrinos are created via several interactions. In general, the expected flux of these cosmogenic neutrinos depends on multiple parameters describing the sources and propagation of UHECRs. However, using CRPropa, we show that a 'sweet spot' occurs at a neutrino energy of ~1 EeV. At that energy this flux only depends strongly on two...
The Telescope Array Low-energy Extension (TALE) experiment is a hybrid air shower detector for observation of air showers produced by very high energy cosmic rays above 10^16.5 eV.TALE is located at the north part of the Telescope Array (TA) experiment site in the western desert of Utah, USA. TALE has a surface detector (SD) array made up of 103 scintillation counters, including 40 with 400 m...
The Track Ultraviolet Setup (TUS) detector was launched on April 28, 2016 as a part of the scientific payload of the Lomonosov satellite. TUS is a path-finder mission for future space-based observation of Extreme Energy Cosmic Rays (EECRs, E > 5x10^19 eV) with experiments such as K-EUSO. TUS data offer the opportunity to develop strategies in the analysis and reconstruction of the events which...
EUSO-SPB1 was a balloon-borne mission of the JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) Program aiming at the observation of UHECRs from space. The EUSO-SPB1 telescope was a fluorescence detector with a 1 m2 Fresnel refractive optics and a focal surface covered with 36 multi-anode photomultiplier tubes for a total of 2304 channels covering ~11 degrees FOV. Each...
In order to get the primary energy of cosmic rays from their extensive air showers using the fluorescence detection technique, the invisible energy should be added to the measured calorimetric energy. The invisible energy is the energy carried away by particles that do not deposit all their energy in the atmosphere.
It has traditionally been calculated using Monte Carlo simulations that are...
An upgrade of the present IceCube surface array (IceTop) with scintillation detectors and possibly radio antennas is foreseen. The enhanced array will calibrate the impact of snow accumulation on the reconstruction of cosmic-ray showers detected by IceTop as well as improve the veto capabilities of the surface array. In addition, such a hybrid surface array of radio antennas, scintillators...
One of the uncertainties in ultrahigh energy cosmic ray (UHECR) observation derives from the hadronic interaction model used for air shower Monte-Carlo (MC) simulations. One may test the hadronic interaction models by comparing the measured number of muons observed at the ground from UHECR induced air showers with the MC prediction.
The Telescope Array (TA) is the largest experiment in the...
As part of the upgrade of the Pierre Auger Observatory, the AMIGA (Auger Muons and Infill for the Ground Array) underground muon detector extension will allow for direct muon measurements for showers falling into the 750m SD vertical array. We optimized the AMIGA muon reconstruction procedure by introducing a geometrical correction for muons leaving a signal in multiple detector strips due to...
The Telescope Array (TA) is the largest ultra-high-energy cosmic-ray (UHECR) detector in the northern hemisphere, which consists of 507 surface detector (SD) covering a total 700 km^2 and three fluorescence detector stations. In this presentation, we will summarize recent results on the search for directional anisotropy of UHECRs using the latest data set collected by the TA SD array.
The distribution of the arrival directions of ultra-high energy cosmic rays is, together with the spectrum and the mass composition, a harbinger of their nature and origin. As such, it has been the subject of intense studies at the Pierre Auger Observatory since its inception in 2004, with two main lines of analysis being pursued at different angular scales and at different energies. One...
Despite deflections by Galactic and extragalactic magnetic fields, the distribution of the flux of ultra-high energy cosmic rays (UHECRs) over the celestial sphere remains a most promising observable for the identification of their sources. This distribution is remarkably close to being isotropic. Thanks to a large number of detected events over the past years, a large-scale anisotropy at...
The Telescope Array (TA) experiment identified a concentration of ultra-high-energy cosmic ray (UHECR) events on the sky, so-called hotspot. Besides the hotspot, the arrival directions of TA events show another characteristic feature, i.e., a deficit of events toward the Virgo cluster. As an effort to understand the sky distribution of TA events, we investigated the structures of galaxies...
I'll discuss the differences between contemporary Monte Carlo generators of high energy hadronic interactions and their impact on the interpretation of experimental data on ultra-high energy cosmic rays (UHECRs). In particular, key directions for model improvements will be outlined. The prospect for a coherent interpretation of the data in terms of the primary composition will be investigated.
Extensive air showers are complex objects, resulting of billions of
particle reactions initiated by single cosmic ray at ultra-high-energy.
Their characteristics are sensitive both to the mass of the primary
cosmic ray and to the details of hadronic interactions. Many of the
interactions that determine the shower features occur in energy and kinematic
regions beyond those tested by human-made...
Telescope Array (TA) is measuring ultra-high energy cosmic rays in the Northern hemisphere since 2008. Using hybrid detectors namely surface detector array (SD) and fluorescence telescopes (FD), TA can measure the lateral and longitudinal developments of extensive air showers, respectively, in detail. Recent analysis of SD data reveals the excess of muons at large distance from the shower core...
Unambiguously determining the mass composition of ultra-high energy cosmic rays is a key challenge at the frontier of cosmic ray research. The mass composition is inferred from air shower observables using air shower simulations, which rely on hadronic interaction models. Current hadronic interaction models lead to varying interpretations, therefore tests of hadronic interaction models with...
KLYPVE-EUSO (K-EUSO) is a planned orbital detector of ultra-high energy cosmic rays (UHECRs), which is to be deployed on board the International Space Station. K-EUSO is expected to have an almost uniform exposure over the celestial sphere and register from 120 to 500 UHECRs at energies above ~57 EeV in a 2-year mission. We employ the CRPropa3 package to estimate prospects of testing the...
The fluorescence detector technique is using the atmosphere
as a calorimeter. Besides the precise monitoring of the parameters
of the atmosphere a proper knowledge of the optical properties in
the UV range of all optical components involved in the measurements
of the fluorescence light is vital.
Until now, the end-to-end calibration was performed with a 4.5 m^2 large,
uniformly lit light...
The prototype array of the underground muon detector as part of the AMIGA enhancement was built and operated until November 2017. During this engineering phase, the array was composed of seven stations. The detector design as well as its performance for physics deliverables were validated and optimized. The most notable improvement was the selection of silicon photo-multipliers rather than...
The average profiles of cosmic ray showers developing with traversed atmospheric depth are measured for the first time, with the Fluorescence Detectors at the Pierre Auger Observatory. The profile shapes are well reproduced by the Gaisser-Hillas parametrization, at the 1% level in a 500 g/cm2 interval around the shower maximum, for cosmic rays with log(E/eV) > 17.8. The results are quantified...
The Auger Engineering Radio Array (AERA) complements the Pierre Auger Observatory with 150 radio-antenna stations measuring in the
frequency range from 30 to 80 MHz. With an instrumented area of 17 km^2, the array constitutes the largest cosmic-ray radio detector
built to date, allowing us to do multi-hybrid measurements of cosmic rays in the energy range of ~10^17 eV up to several 10^18...
The atmospheric aerosol monitoring system of the Pierre Auger Observatory, initiated in 2004, continues to operate smoothly. Two laser facilities (Central Laser Facility, CLF and eXtreme Laser Facility, XLF) each fire sets of 50 laser shots four times per hour during Fluorescence Detector (FD) shifts.
The FD measures these UV laser tracks. Analysis of these tracks yields hourly measurements...
The average number of muons in air showers and its connection with the development of air showers has been studied extensively in the past. With the upcoming detector upgrades, UHECR observatories will be able to also probe higher moments of the muon distribution. Here we present a study of the physics of the fluctuations of the muon content. In addition to proving that the fluctuations must...
With the recent results of large hybrid air shower experiments, it is clear that the simulations of the hadronic interactions are not good enough to obtain a consistent description of the observations. Even the most recent models tuned after the first run of LHC show significant discrepancy with air shower data. Since then many more data have been collected at LHC and lower energies which are...
The LHCf experiment aims for measurements of the forward neutral particles at an LHC interaction point to test hadronic interaction models which are widely used in cosmic-ray air-shower simulations. The LHCf had an operation with proton-proton collisions at the center of mass collision energy of 13 TeV in 2015. The LHCf detectors were composed of sampling and imaging calorimeters and they were...
Auger@TA is a joint experimental program of the Telescope Array experiment (TA) and the Pierre Auger Observatory (Auger), the two leading ultra-high energy cosmic-ray experiments located respectively in the northern and southern hemispheres. The aim of the program is to achieve a cross-calibration of the Surface Detector (SD) from both experiments. The first phase of this joint effort is...
We report on a study about the mechanisms of muon production during the development of extended air showers initiated by ultra-high-energy cosmic rays. In particular, we analyze and discuss on the observed discrepancies between experimental measurements and simulated data.
IceCube is a cubic-kilometer Cherenkov detector in the deep ice at the geographic South Pole. The dominant event yield is produced by penetrating atmospheric muons with energies above several 100 GeV. Due to its large detector volume, IceCube provides unique opportunities to study atmospheric muons with large statistics in great detail. Measurements of the energy spectrum and the lateral...
The origin and nature of Ultra-High Energy Cosmic Rays (UHECRs) remain unsolved in contemporary astroparticle physics. To give an answer to these questions is rather challenging because of the extremely low flux of a few per km^2 per century at extreme energies such as E > 5 × 10^19eV. The objective of the JEM-EUSO program, Extreme Universe Space Observatory, is the realization of a space...
We present the current version of generator GHOST which can be used in the simulation of Non Diffractive (ND),Non Single Diffractive (NSD), single diffractive (SD) and double diffractive (DD) events at cosmic ray energies.
The generator is based on four-gaussian parameterization of pseudorapidity distribution which is related to the leading cluster approach in distribution of secondary...
The TAx4 experiment is a project to observe highest energy cosmic rays by expanding the detection area of the TA experiment with newly constructed surface detectors (SDs) and fluorescence detectors (FDs). The construction of both SDs and FDs is ongoing. New SDs are arranged in a square grid with 2.08 km spacing at the north east and south east of the TA SD array. Field of view of new FDs...
The world largest exposure to ultra high energy cosmic rays accumulated by the Pierre Auger Observatory lead to major advances in our understanding of their properties, but the many unknowns about the nature and distribution of the sources, the primary composition and the underlying hadronic interactions prevent the emergence of a uniquely consistent picture.
The new perspectives opened by...
The origin and nature of ultrahigh-energy cosmic rays (UHECRs) is one of the most intriguing mys- teries in astroparticle physics. The two largest observatories currently in operation, the Telescope Array Experiment in central Utah, USA, and the Pierre Auger Observatory in western Argentina, have been steadily observing UHECRs in both hemispheres for over a decade. We highlight the latest...
In the future, ultra-high energy cosmic ray (UHECR) observatory will be expanded due to the small flux. Then, cost reduction is useful strategy to realize a huge scale observatory. For this purpose, we are developing a simple structure cosmic ray detector named as Cosmic Ray Air Fluorescence Fresnel-lens Telescope (CRAFFT). We deployed CRAFFT detectors at the Telescope Array site and performed...
High-energy cosmic rays impinging on the atmosphere of the Earth induce cascades of secondary particles, the extensive air showers. Many particles in the showers are electrons and positrons. Due to interactions with the magnetic field of the Earth they emit radiation with frequencies of several tens of MHz. In the last years huge progress has been achieved in this field through strong...
Radio techniques show the most promise for measuring and characterizing
the astrophysical neutrino flux above about 10^17 eV. Complementary strategies include observing a target volume from a distance and deploying sensors in the target volume itself. I will focus on the current status of experiments utilizing the latter strategy, in-ice radio arrays. I will give an overview of results from...
The Giant Radio Array for Neutrino Detection (GRAND) aims at detecting ultra-high-energy extraterrestrial neutrinos via the extensive air showers induced by the decay of tau leptons created in the interaction of neutrinos under the Earth's surface. Consisting of an array of $\sim200\,000$ radio antennas deployed over $\sim200\,000\,$km$^2$, GRAND plans to reach, for the first time, a...
Significant progress has been made in the last decade in the
field of Ultra-High-Energy Cosmic Rays (UHECRs), thanks to the operation
of large ground-based detectors and to the renewed theoretical interest
that they triggered. While multi-messenger astronomy is rapidly developing
worldwide, the sources of the charged messengers, namely the cosmic rays,
are still to be determined, and the...
Developed as a NASA Astrophysics Probe mission concept study, the Probe Of Multi-Messenger Astrophysics (POEMMA) science goals are to identify the sources of ultra-high energy cosmic rays (UHECRs) and to observe cosmic neutrinos above 10 PeV. POEMMA consists of two satellites flying in loose formation at 525 km altitudes. A novel focal plane design is optimized to observe the UV air...
The very recent anisotropy at highest UHECR energies is smootly clustering in several wide spots (or hot spots) : Cen A, M82, NGC 253 are at a few Mpc distance and are possible the main sources of these anisotropies in AUGER and TA data.
Because the Virgo absence and the UHECR airshower slat depth most of UHECR are lightest nuclei.
Other additional growing clustering may be related to well...
The hypothesis of existence of the new stable heavy hadrons in the cosmic rays is proposed. It follows from the comprehensive study of extensive air showers in
the hybrid experiment HADRON which was carried out at the level 685 g/cm^2 of the Tien Shan mountains. The spectra of the high energy hadrons inside the cores of extensive air showers were obtained for the first time by means of the...
We consider the pion production in collisions of ultra high energy protons with the MBR . The probability of such a process is calculated, and is found to be in the strong dependence on the quark-gluon vertex at high energies in the hard QCD limit. The relation of the obtained results to the experimental knee in the energy spectrum of ultra high energy protons allows us to get information...
The discover in AUGER of a dipole remarkable anisotropy it is statistically the most strong in the whole Ultra High Energy Cosmic Ray history. It implies a dipole anisotropy almost overlapping to the Argo-Hawc one at tens TeV energy. However
the tens TeV anisotropy it must be very local (galactic) one while the UHECR are supposed to be (as their name suggest) Cosmic ones.
We show that there...
