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In this paper, we investigate the topological photon sphere from two distinct perspectives. In the first view, we examine the existence and characteristics of topological photon (anti-photon) spheres for black holes with different structures, such as Einstein–Young–Mills non-minimal, AdS black holes surrounded by Chaplygin-like dark fluid, and Bardeen-like black holes in Einstein–Gauss–Bonnet gravity. Furthermore, we delve into the deeper perspective of the necessity of photon spheres for super-compact gravitational structures such as black holes. By leveraging this necessity, we propose a classification of the parameter space of black hole models based on the existence and positioning of photon spheres. This approach enables the determination of parameter ranges that delineate whether a solution represents a black hole or a naked singularity. In essence, the paper illustrates the utility of the photon sphere as a notable test for establishing the permissible and non-permissible parameter ranges within specific theories of black hole solutions. [ABSTRACT FROM AUTHOR]

This paper presents analyses of cosmic-ray-induced neutron measurements spanning from 2016 to 2023 at the Concordia Antarctic high-altitude station. Environmental and systematic effects are meticulously considered in both long-term and short-term perspectives. The study delves into space weather cases, focusing on solar events in September 2017 and October 2021, along with a specific examination of the impact of the Atmospheric River in March 2022. The paper explores the valuable contribution of modeling to data analyses, particularly its capacity to infer solar modulation from neutron spectra. All analyses integrate modulations of the neutron spectrum, with a specific emphasis on short-term events, representing the principal contribution of the spectral measurements. [ABSTRACT FROM AUTHOR]

The ISS-CREAM instrument is the modified version of the Cosmic Ray Energetics And Mass (CREAM) experiment, which was flown on balloons multiple times over Antarctica and later installed on the International Space Station (ISS). Its primary objective is to measure the energy spectra of individual cosmic-ray elements for the charge range of Z = 1 to Z = 26, in the energy range of ∼ 1012 to ∼ 1015 eV. The instrument comprises a tungsten/scintillator calorimeter and a pixelated silicon charge detector as primary detectors to determine the energy and charge of cosmic rays. Additionally, it includes top and bottom scintillator counting detectors and a boronated scintillator detector to differentiate between electrons and hadrons for multi-TeV electron measurements. The ISS-CREAM instrument was installed on the ISS in August 2017 and operated until February 2019. This paper provides an overview of the instrument, focusing on its detectors, trigger systems, common electronics, and power systems. The paper highlights the modifications made to these components to optimize their performance for ISS operations. [ABSTRACT FROM AUTHOR]

In small balloon missions, some in situ radiation is added to the targeted strong persistent astronomical sources (such as, the Sun, Crab, Cygnus X-1, etc.) or transient sources, such as solar flares, gamma-ray bursts, etc., during their detection, i.e., the background radiation. For measurement and modeling of background radiation, we use the data of the low-cost, small, stratospheric, high-altitude balloon-borne missions conducted by Indian Centre for Space Physics. In this paper, we show several models to estimate the background counts where the strong X-ray sources are detected at the altitude range of ∼ 35 – 42 km even in the absence of onboard pointing system and severe atmospheric absorption. For all data analysis purposes, the photons detected in the detector are in the energy range of 10 – 80 keV. Moreover, we found that the observed data is within ± 1 σ of the calculated background model. Finally, using these background models, we estimate the spectra and luminosity of the Crab nebula and the black hole candidate Cygnus X-1, which agree with the previously published results. [ABSTRACT FROM AUTHOR]

Seasonal variations of atmospheric muons are traditionally interpreted in terms of an effective temperature that relates the atmospheric temperature profile at a given time to the dependence of muon production on atmospheric depth. This paper aims to review and generalize the treatment of muon production and effective temperature that has been used to interpret seasonal variations of atmospheric muons by many experiments. The formalism is developed both in integral form – for application to compact detectors at a fixed depth that record all muons with E μ > E μ min – and in differential form — for application to extended detectors like IceCube, KM3NeT, and Baikal-GVD, where the rates are proportional to energy-dependent effective areas. [ABSTRACT FROM AUTHOR]

The experiment AMS on the International Space-Station has produced accurate cosmic ray spectra for many chemical elements, both primaries like He, C, O, Fe, other cosmic ray (CR) primaries like Ne, Mg, and Si, secondaries like Li, Be, B, and of mixed provenance, like N, Na, and Al. The AMS spectra demonstrate that interaction is seriously diminishing fluxes up to a rigidity of about 100 GV, and so the existing models for CR interaction have to be re-examined. Based on earlier well-established ideas a model is proposed here that focusses on the cosmic ray interaction first in the wind shock shell of super giant stars, when the supernova driven shock races through, and second in the OB-Superbubble surrounding the SN: These stars include both red super-giant stars and blue super-giant stars; both produce black holes in their explosion, and drive winds and jets with electric currents. Variability of these winds or jets gives rise to temporary electric fields, as has recently been demonstrated, and discharge (so lightning) acceleration gives steep spectra, with synchrotron losses to p − 5 in momentum p ; these spectra are typically observed in both Galactic and some extragalactic radio filaments. Analogous hadron spectra p − 4 excite a flat spectrum of magnetic irregularities in the bubble zone, which in turn yields a steep dependence of residence time versus energy, with power − 5 / 3. This spectrum is indicated by the AMS data and appears to be required to explain the CR spectra below 100 GV. The emphasis in this paper is to work out the interaction of the freshly accelerated cosmic ray particles. In the model presented here the interaction is derived as a function of time, and then integrated, or developed to long times. The model gives a rigidity dependence of the secondary/primary ratio of slope − 1 / 3 as well as the strong reduction of the primary fluxes below a rigidity of about 100 GV, relative to a power-law injection spectrum, with slope + 2. The two key aspects based on blue super-giant stars and a magnetic irregularity spectrum in the bubble zone given by lightning are (i) a much larger column of interaction, allowed because of heavy element enrichment of the interaction zone, and (ii) even He, C, and O may have a small secondary contribution, as the difference to the Fe spectrum suggests; this small secondary component is visible in the 3 He/ 4 He ratio. The model may also explain the spectrum of CR anti-protons, the gamma-ray spectra of the Galaxy and the high energy neutrino spectrum of our Galaxy, including also red super-giant stars as sources. ISM-SNe, i.e. SN Ia and neutron-star SNe, contribute to CR protons and CR He nuclei. [ABSTRACT FROM AUTHOR]

In their seminal work, Morris and Thorne (1988) introduced the concept of traversable wormholes (WHs), which are geometric structures serving as bridges to connect two distinct spacetimes or different points within the same spacetime. The properties of these WHs are determined by the choice of the shape function. Extensive research has been conducted in the literature on WHs within modified theories of gravity, considering various types of shape functions. In this paper, we focus on deriving the simplest solutions for traversable WHs within the framework of f (R , T) gravity. Our specific focus lies on the functional form f (R , T) = R + α R 2 + λ T , where R represents the Ricci scalar and T denotes the trace of the energy–momentum tensor. By incorporating quadratic geometric and linear material corrections, we demonstrate that the matter content of WHs can obediently conform to the energy conditions (ECs). This study significantly advances our understanding of WHs within the context of modified gravity. Our findings shed new light on the behavior and properties of WHs, highlighting their compatibility with the f (R , T) gravity framework. By unveiling the ability of WHs to adhere to ECs through the inclusion of geometric and material corrections, we provide groundbreaking insights into these intriguing objects. Overall, our research contributes to the broader field of gravitational physics by presenting a unique perspective on WH modeling. By exploring WHs within the f (R , T) gravity framework and demonstrating their conformity to ECs, we expand our knowledge of these fascinating structures and pave the way for further investigations in this area. [ABSTRACT FROM AUTHOR]

The KM2A is the largest sub-array of the Large High Altitude Air Shower Observatory (LHAASO). It consists of 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). The data recorded by the EDs and MDs are used to reconstruct primary information of cosmic-ray and gamma-ray showers. To ensure the reliability of the LHAASO-KM2A data, a three-level quality control system has been established. It is used to monitor the status of detector units, stability of reconstructed parameters and the performance of the array based on observations of the Crab Nebula and Moon shadow. This paper will introduce the control system and its application on the LHAASO-KM2A data collected from August 2021 to July 2023. During this period, the pointing and angular resolution of the array were stable. From the observations of the Moon shadow and Crab Nebula, the results achieved using the two methods are consistent with each other. For example, according to the observation of the Crab Nebula with KM2A at energies from 25 TeV to 100 TeV, the time averaged pointing errors are estimated to be − 0. 003 ° ± 0. 005 ° and 0. 001 ° ± 0. 006 ° in the R.A. and Dec directions, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a framework for the derivation of a noise budget and the subsequent utilization in the optimization of the control design, using the laser frequency stabilization loop in the Virgo interferometer, which is a complex nested feedback system, as an experimental case study. First, the system dynamics and noise sources are modeled and experimentally verified to produce the noise budget, after which an optimization problem using the H 2 norm is formulated and tailored to the specific design requirements for the detector. The structure of the synthesized controller is then used to produce an improved control design. Experimental verification of the developed controller on the Virgo interferometer shows roughly a factor 3 reduction in root-mean-square error, illustrating the effectiveness of the presented method. [ABSTRACT FROM AUTHOR]

This paper mainly presents updated constraints on several types of early dark energy (EDE) models proposed by V. Pettorino et al. using observations of cosmic microwave background radiation (CMB) from Planck satellite, the Pantheon Type Ia supernovae (SNIa) sample, and baryon acoustic oscillation (BAO) measurements. The results yield stringent upper limits on the constant EDE fraction parameter Ω e. While the present equation of state (EoS) of dark energy w 0 in the EDE1 model suggests a mild tendency towards a value less than − 1 , these models remain compatible with the Λ CDM scenario. Partly as a result of this slight tendency towards phantom late-time physics, EDE1 model supports a higher Hubble constant value, potentially narrowing the Hubble tension gap. The global fitting results also align with the notion that the constraint ability on Ω e weakens when dark energy is present only over a limited period after last scattering. Furthermore, by using the formalism of Fisher information matrix, we forecast uncertainties in the measured parameters of EDE models from the next-generation "Stage 4" CMB (CMB-S4) experiment. Forecasted precision of w 0 and Ω e surpasses certain prior works, and most other basic parameters exhibit significantly higher limit precision compared to Planck 2018 results within the Λ CDM framework. To confirm the presence of EDE within the EDE1 ∼ EDE4 parameterization frameworks, further advancements in observations are crucial. [ABSTRACT FROM AUTHOR]

Using the cosmological date sets, the cosmological parameters are constrained in this paper, with well known phantom behavioural Hubble parameter. To understand the dynamics of the Weyl type f (Q , T) gravity, functional form of f (Q , T) has been introduced, where Q and T respectively represents the nonmetricity scalar that depends on the Weyl vector (Q = − 6 w 2) and trace of energy–momentum tensor. Using the constrained values of the parameters, the other geometrical parameters are analysed and the accelerating behaviour has been shown. The dynamical parameters and energy conditions are also analysed. Further to get the complete evolutionary behaviour of the Universe, the dynamical system analysis has been performed. • Late time cosmic acceleration behaviour obtained in Weyl type f (Q , T) gravity. • The parameters are constrained through using the cosmological datasets. • Stable behaviour obtained at late time from the dynamical system analysis. [ABSTRACT FROM AUTHOR]

The theory of cosmic inflation has received a great amount of deserved attention in recent years due to it's stunning predictions about the early universe. Alongside the usual cold inflation paradigm, warm inflation has garnered a huge amount of interest in modern inflationary studies. It's peculiar features and specifically different predictions from cold inflation have led to a substantial amount of literature about it. Various modified cosmological scenarios have also been studied in the warm inflationary regime. In this work, we introduce the exact solution approach for warm inflation. This approach allows one to directly study warm inflationary regime in a variety of modified cosmological scenarios. We begin by outlining our method and show that it generalizes the modified Friedmann approach of Del Campo, and reduces to the well known Hamilton–Jacobi formalism for inflation in particular limits. We also find the perturbation spectra for cosmological and tensor perturbations in the early universe, and then apply our method to study warm inflation in a Tsallis entropy modified Friedmann universe. We end our paper with some concluding remarks on the domain of applicability of our work. [ABSTRACT FROM AUTHOR]

This paper presents Taylor expansions for the imaging and timing characteristics of spherical optical systems with infinitesimal mirror facets, sometimes referred to as "modified Davies–Cotton" telescopes. Such a system comprises a discontinuous spherical mirror surface whose curvature radius is different from its focal length, and whose mirrors are aligned to suppress spherical aberration. Configurations that range between two "optima" are, one of which minimises tangential comatic aberration and the other that minimises timing dispersion. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the behavior of coupled quintessence at inflection point in the accelerated expansion of the universe. We consider spatially homogeneous quintessence coupled with the matter with two coupling parameters as Q = 3 α H ρ m and Q = 3 β ρ m ̇ . We obtain the inflection point for the power law form of potential V (ϕ) = V 3 (ϕ − ϕ 0) 3 and its generalized form in two coupled quintessence models. [ABSTRACT FROM AUTHOR]

Early dark energy (EDE) is one of the most promising possibilities in order to resolve the Hubble tension: the discrepancy between the locally measured and cosmologically inferred values of the Hubble constant. In this paper we propose a toy model of unified EDE and late dark energy (DE), driven by a scalar field in the context of α -attractors. The field provides an injection of a subdominant dark energy component near matter-radiation equality, and redshifts away shortly after via free-fall, later refreezing to become late-time DE at the present day. Using reasonable estimates of the current constraints on EDE from the literature, we find that the parameter space is narrow but viable, making our model readily falsifiable. Since our model is non-oscillatory, the density of the field decays faster than the usual oscillatory EDE, thereby possibly achieving better agreement with observations. [ABSTRACT FROM AUTHOR]

Major Atmospheric Cherenkov Experiment (MACE) is a large telescope commissioned at Ladakh region of India. It consists of many subsystems operating in synchronization to perform successful observations. The paper introduces a robust, concise and autonomous operator console to operate, control and monitor the entire experiment, providing workflow management, autonomous schedule-based observation, orchestration of data acquisition and monitoring of telemetry data, while maintaining safety of subsystems. Using a synchronised controller-observer pattern the highly-automated operator console carries out the entire observation on a single click from either local or from remote geographic locations. Remote operation of the telescope from BARC, Mumbai allowed pre-commissioning tests, troubleshooting and upgradation of the system from a more convenient environment. [ABSTRACT FROM AUTHOR]

Abstract One of the main purposes of the DArk Matter Particle Explorer (DAMPE) is to measure the cosmic ray nuclei up to several tens of TeV or beyond, whose origin and propagation remains a hot topic in astrophysics. The Plastic Scintillator Detector (PSD) on top of DAMPE is designed to measure the charges of cosmic ray nuclei from H to Fe and serves as a veto detector for discriminating gamma-rays from charged particles. We propose in this paper a charge reconstruction procedure to optimize the PSD performance in charge measurement. Essentials of our approach, including track finding, alignment of PSD, light attenuation correction, quenching and equalization correction are described detailedly in this paper after a brief description of the structure and operational principle of the PSD. Our results show that the PSD works very well and almost all the elements in cosmic rays from H to Fe are clearly identified in the charge spectrum. [ABSTRACT FROM AUTHOR]

Highlights • Reply to rebuttal and new papers by Sturrock et al. which repeat old claims. • The radon experiment at GSI is susceptible to sunshine and rainfall. • There is no evidence that solar or cosmic neutrinos induce radioactive decay. • There is no relationship between radioactive decay and solar rotation. Abstract Sturrock et al. have published a "rebuttal" to a paper by Pommé et al. who refuted their claim that variations in a radon decay experiment at the Geological Survey of Israel (GSI) can be associated with solar rotation. Sturrock et al. misinterpret the variability of the decay rates in the gamma counter to assert influences by solar and cosmic neutrinos on beta decay and draw unsubstantiated conclusions about solar dynamics. Evidence suggests that the radon measurements were susceptible to solar irradiance and rainfall, whereas there is no indication that radioactive decay is influenced by the solar neutrino flux. In this reply to the rebuttal, the arguments raised by Sturrock et al. are scrutinised. [ABSTRACT FROM AUTHOR]

It was shown that a standard ring of light can be imagined outside the event horizon for stationary rotating four-dimensional black holes with axial symmetry using the topological method (Cunha, 2020; Wei and Shao-Wen, 2020). Based on this concept, in this paper, we investigate the topological charge and the conditions of existence of the photon sphere (PS) for a hyperscaling violation (HSV) black hole with various values of the parameters of this model. Then, after carrying out a detailed analysis, we show the conventional topological classes viz Q = − 1 for the mentioned black hole and Q = 0 for the naked singularities. Also, we propose a new topological class for naked singularities (Q = + 1) with respect to z ≥ 1. We also determined that z ≥ 2 , it either shows a naked singularity form with total topological charge + 1 or has no solution. Therefore, we have the black hole solution only in 1 ≤ z < 2. Then, we will use two different methods, namely the temperature (Duan's topological current Φ -mapping theory) and the generalized Helmholtz free energy method, to study the topological classes of our black hole. By considering the black hole mentioned, we discuss the critical and zero points (topological charges and topological numbers) for different parameters of hyperscaling violating black holes, such as (z , θ ¯) and other free parameters, and study their thermodynamic topology. We observe that for a given value of the parameters 1 ≤ z < 2 , θ ¯ , and other free parameters, there exist two total topological charges (Q t o t a l = − 1 , 0) with the same phase structure for the T method and total topological numbers (W = + 1) for the generalized Helmholtz free energy method. Additionally, we summarize the results for each study as photon sphere, temperature, and generalized Helmholtz free energy in some figures and tables. Finally, we compare our findings with other related studies in the literature. [ABSTRACT FROM AUTHOR]

The present white paper is submitted as part of the "Snowmass" process to help inform the long-term plans of the United States Department of Energy and the National Science Foundation for high-energy physics. It summarizes the science questions driving the Ultra-High-Energy Cosmic-Ray (UHECR) community and provides recommendations on the strategy to answer them in the next two decades. [ABSTRACT FROM AUTHOR]

Over the last years, radio detection has matured to become a competitive method for the detection of air showers. Arrays of thousands of antennas are now envisioned for the detection of cosmic rays of ultra high energy or neutrinos of astrophysical origin. The data exploitation of such detectors requires to run massive air-shower simulations to evaluate the radio signal at each antenna position. In order to reduce the associated computational cost, we have developed a semi-analytical method for the computation of the emitted radio signal called Radio Morphing. The method consists in computing the radio signal of any air-shower at any location from the simulation of one single reference shower at given positions by (i) a scaling of the electric-field amplitude of this reference shower, (ii) an isometry on the simulated positions and (iii) an interpolation of the radio pulse at the desired position. This technique enables one to compute electric field time traces with characteristics very similar to those obtained with standard computation methods, but with computation times reduced by several orders of magnitude. In this paper, we present this novel tool, explain its methodology, and discuss its limitations. Furthermore, we validate the method on a typical event set for the future GRAND experiment showing that the calculated peak amplitudes are consistent with the results from ZHAireS simulations with a mean offset of + 8.5 % and a standard deviation of 27.2% in this specific case. This overestimation of the signal strength by Radio Morphing arises mainly from the choice of the underlying reference shower. [ABSTRACT FROM AUTHOR]

AMoRE (Advanced Mo-based Rare process Experiment) is an experiment to search a neutrinoless double-beta decay of 100Mo in molybdate crystals. The neutron and muon-induced backgrounds are crucial to obtain the zero-background level (< 10 − 5 counts/(keV · kg · yr)) for the AMoRE-II experiment, which is the second phase of the AMoRE project, planned to run at YEMI underground laboratory. To evaluate the effects of neutron and muon-induced backgrounds, we performed Geant4 Monte Carlo simulations and studied a shielding strategy for the AMORE-II experiment. Neutron-induced backgrounds were also included in the study. In this paper, we estimated the background level in the presence of possible shielding structures, which meet the background requirement for the AMoRE-II experiment. [ABSTRACT FROM AUTHOR]

Seven years after the first direct detection of gravitational waves, from the collision of two black holes, the field of gravitational wave astronomy is firmly established. A first detection of continuous gravitational waves from rapidly-spinning neutron stars could be the field's next big discovery. I review the last twenty years of efforts to detect continuous gravitational waves using the LIGO and Virgo gravitational wave detectors. I summarise the model of a continuous gravitational wave signal, the challenges to finding such signals in noisy data, and the data analysis algorithms that have been developed to address those challenges. I present a quantitative analysis of 297 continuous wave searches from 80 papers, published from 2003 to 2022, and compare their sensitivities and coverage of the signal model parameter space. [ABSTRACT FROM AUTHOR]

Although high-energy astrophysical neutrinos were discovered in 2013, their origin is still unknown. Aiming for the identification of an electromagnetic counterpart of a rapidly fading source, we have implemented a realtime analysis framework for the IceCube neutrino observatory. Several analyses selecting neutrinos of astrophysical origin are now operating in realtime at the detector site in Antarctica and are producing alerts for the community to enable rapid follow-up observations. The goal of these observations is to locate the astrophysical objects responsible for these neutrino signals. This paper highlights the infrastructure in place both at the South Pole site and at IceCube facilities in the north that have enabled this fast follow-up program to be implemented. Additionally, this paper presents the first realtime analyses to be activated within this framework, highlights their sensitivities to astrophysical neutrinos and background event rates, and presents an outlook for future discoveries. [ABSTRACT FROM AUTHOR]

In August 2015, the CALorimetric Electron Telescope (CALET), designed for long exposure observations of high energy cosmic rays, docked with the International Space Station (ISS) and shortly thereafter began to collect data. CALET will measure the cosmic ray electron spectrum over the energy range of 1 GeV to 20 TeV with a very high resolution of 2% above 100 GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging (TASC and IMC) units. Each TASC readout channel must be carefully calibrated over the extremely wide dynamic range of CALET that spans six orders of magnitude in order to obtain a degree of calibration accuracy matching the resolution of energy measurements. These calibrations consist of calculating the conversion factors between ADC units and energy deposits, ensuring linearity over each gain range, and providing a seamless transition between neighboring gain ranges. This paper describes these calibration methods in detail, along with the resulting data and associated accuracies. The results presented in this paper show that a sufficient accuracy was achieved for the calibrations of each channel in order to obtain a suitable resolution over the entire dynamic range of the electron spectrum measurement. [ABSTRACT FROM AUTHOR]

Source detection in counting type experiments such as Cherenkov telescopes often involves the application of the classical Eq. (17) from the paper of Li & Ma (1983) to discrete on- and off-source regions. The on-source region is typically a circular area with radius θ in which the signal is expected to appear with the shape of the instrument point spread function (PSF). This paper addresses the question of what is the θ that maximises the probability of detection for a given PSF width and background event density. In the high count number limit and assuming a Gaussian PSF profile, the optimum is found to be at ζ ∞ 2 ≈ 2.51 times the squared PSF width σ PSF 39 2 . While this number is shown to be a good choice in many cases, a dynamic formula for cases of lower count numbers, which favour larger on-source regions, is given. The recipe to get to this parametrisation can also be applied to cases with a non-Gaussian PSF. This result can standardise and simplify analysis procedures, reduce trials and eliminate the need for experience-based ad hoc cut definitions or expensive case-by-case Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

Motivated by the possible existence of other universes, with different values for the fundamental constants, this paper considers stellar models in universes where 8 Be is stable. Many previous authors have noted that stars in our universe would have difficulty producing carbon and other heavy elements in the absence of the well-known 12 C resonance at 7.6 MeV. This resonance is necessary because 8 Be is unstable in our universe, so that carbon must be produced via the triple alpha reaction to achieve the requisite abundance. Although a moderate change in the energy of the resonance (200–300 keV) will indeed affect carbon production, an even smaller change in the binding energy of beryllium (∼100 keV) would allow 8 Be to be stable. A stable isotope with A = 8 would obviate the need for the triple alpha process in general, and the 12 C resonance in particular, for carbon production. This paper explores the possibility that 8 Be can be stable in other universes. Simple nuclear considerations indicate that bound states can be realized, with binding energy ∼ 0.1 − 1 MeV, if the fundamental constants vary by a ∼ few − 10 %. In such cases, 8 Be can be synthesized through helium burning, and 12 C can be produced later through nuclear burning of beryllium. This paper focuses on stellar models that burn helium into beryllium; once the universe in question has a supply of stable beryllium, carbon production can take place during subsequent evolution in the same star or in later stellar generations. Using both a semi-analytic stellar structure model as well as a state-of-the-art stellar evolution code, we find that viable stellar configurations that produce beryllium exist over a wide range of parameter space. Finally, we demonstrate that carbon can be produced during later evolutionary stages. [ABSTRACT FROM AUTHOR]

The rate of extensive air-showers observed with imaging air-Cherenkov telescopes is zenith angle dependent. This effect originates from the increasing geometrical distance of the observed shower to the telescope with increasing zenith distance. This paper investigates how this alters the observed image and how this affects the trigger rate as a function of zenith angle. The discussed effects include the change of Cherenkov light yield, of absorption in the atmosphere, of photon density at the aperture and of the image size at the focal plane of the telescope. Based on a simple model for the atmosphere and well-known first principles on the development of extensive air-showers, the zenith angle dependence is expressed analytically. The assumption that most light is emitted from the shower core and mathematical approximations allow to derive an analytical expression describing the zenith angle dependence well with only three free parameters which are directly linked with the underlying physics. This suggests further investigations about how these fit parameters are linked to the properties of the atmosphere and the instrument. Using data published by the First G-APD Cherenkov Telescope, a good match of the fit functions with the data is obtained. For the trigger rate of cosmic rays, the obtained parameters are consistent with the naive expectation. [ABSTRACT FROM AUTHOR]

Abstract The Dark matter Experiment using Argon Pulse-shape discrimination (DEAP) has been designed for a direct detection search for particle dark matter using a single-phase liquid argon target. The projected cross section sensitivity for DEAP-3600 to the spin-independent scattering of Weakly Interacting Massive Particles (WIMPs) on nucleons is 10 − 46 cm 2 for a 100 GeV/ c 2 WIMP mass with a fiducial exposure of 3 tonne-years. This paper describes the physical properties and construction of the DEAP-3600 detector. [ABSTRACT FROM AUTHOR]

Abstract SABRE (Sodium-iodide with Active Background REjection) is a direct dark matter search experiment based on an array of radio-pure NaI(Tl) crystals surrounded by a liquid scintillator veto. Twin SABRE experiments in the Northern and Southern Hemispheres will differentiate a dark matter signal from seasonal and local effects. The experiment is currently in a Proof-of-Principle (PoP) phase, whose goal is to demonstrate that the background rate is low enough to carry out an independent search for a dark matter signal, with sufficient sensitivity to confirm or refute the DAMA result during the following full-scale experimental phase. The impact of background radiation from the detector materials and the experimental site needs to be carefully investigated, including both intrinsic and cosmogenically activated radioactivity. Based on the best knowledge of the most relevant sources of background, we have performed a detailed Monte Carlo study evaluating the expected background in the dark matter search spectral region. The simulation model described in this paper guides the design of the full-scale experiment and will be fundamental for the interpretation of the measured background and hence for the extraction of a possible dark matter signal. [ABSTRACT FROM AUTHOR]

Abstract Motivated by the possible existence of other universes, this paper considers the evolution of massive stars with different values for the fundamental constants. We focus on variations in the triple alpha resonance energy and study its effects on the resulting abundances of 12C, 16O, and larger nuclei. In our universe, the 0 + energy level of carbon supports a resonant nuclear reaction that dominates carbon synthesis in stellar cores and accounts for the observed cosmic abundances. Here we define ΔE R to be the change in this resonant energy level, and show how different values affect the cosmic abundances of the intermediate alpha elements. Using the state of the art computational package MESA , we carry out stellar evolution calculations for massive stars in the range M * = 15 − 40 M ⊙ , and for a wide range of resonance energies. We also include both solar and low metallicity initial conditions. For negative ΔE R , carbon yields are increased relative to standard stellar models, and such universes remain viable as long as the production of carbon nuclei remains energetically favorable, and stars remain stable, down to Δ E R ≈ − 300 keV. For positive ΔE R , carbon yields decrease, but significant abundances can be produced for resonance energy increments up to Δ E R ≈ + 500 keV. Oxygen yields tend to be anti-correlated with those of carbon, and the allowed range in ΔE R is somewhat smaller. We also present yields for neon, magnesium, and silicon. With updated stellar evolution models and a more comprehensive survey of parameter space, these results indicate that the range of viable universes is larger than suggested by earlier studies. [ABSTRACT FROM AUTHOR]

Abstract Ton-scale direct dark matter search experiments should be sensitive to neutrino-induced recoil events from either 8B solar neutrinos or the brief but intense flux from a core collapse supernova in the Milky Way. These low-threshold detectors are sensitive to the very low recoil energies, of order 10 keV, deposited via coherent elastic scatters between supernova neutrinos and target nuclei. Large superheated fluid detectors like PICO-500, a bubble chamber to be initially filled with an active target of 1 t of C 3 F 8 , should see multiple-bubble events from CE ν NS if the detector is live during a neutrino burst from a supernova at a distance up to 10 kpc. This paper discusses conditions under which bubble chambers could be used as an independent measurement in the event of a supernova similar to SN 1987A, with particular sensitivity to the currently less-constrained heavy-lepton ν x channel. [ABSTRACT FROM AUTHOR]

Abstract Atmospheric fluorescence is usually neglected in the reconstruction of the signals registered by Cherenkov telescopes, both IACTs and wide-angle detector arrays. In this paper we quantify the fluorescence contribution to the total light recorded in typical observational configurations. To this end we have implemented the production and tracking of fluorescence light in the CORSIKA code. Both the Cherenkov and fluorescence light distributions on ground (2200 m a.s.l.) have been simulated for γ -ray showers in a wide energy range (10 − 1 − 10 3 TeV). The relative fluorescence contribution has been evaluated as a function of the shower energy and zenith angle. Our results indicate that at distances from the impact point smaller than 200 m the fluorescence contamination is negligible in both types of telescopes. However, at about 1000 m, the contamination in IACTs is around 5%. At these core distances, the signals recorded by wide-angle detectors contain around 45% of atmospheric fluorescence in the PeV region. [ABSTRACT FROM AUTHOR]

Abstract Important observational results have been recently reported on the angular distributions of cosmic rays at all energies, calling into question the perception of cosmic rays a decade ago. These results together with their in-progress interpretations are summarized in this review paper, covering both large-scale and small-scale anisotropies from TeV energies to the highest ones. While the magnetic field in the Galaxy has long been considered as an external data imprinting a quasi-random walk to particles and thus shaping the angular distributions of Galactic cosmic rays through the induced average density gradient, the information encompassed in the angular distributions in the TeV–PeV energy range appear today as a promising tool to infer some properties of the local magnetic field environments. At the highest energies, the extragalactic origin of the particles has been recently determined observationally. While no discrete source of ultrahigh-energy cosmic rays has been identified so far, the noose is tightening around nearby extragalactic objects, and some prospects are discussed. [ABSTRACT FROM AUTHOR]

Abstract The hard X-ray imager of the Sino-French SVOM mission, called ECLAIRs, is dedicated to the detection and near real time localization of cosmic transients in the 4 − 150 keV energy range. ECLAIRs is a wide-field camera using a detection plane consisting of 6400 Schottky CdTe detectors, which makes images of the hard X-ray sky thanks to a coded mask. The detection plane is highly modular, being made of 200 hybrid modules of 4 x 8 pixels (called “XRDPIX”). Based on both an extremely low noise design and the use of innovative technologies, the ECLAIRs instrument will achieve the unprecedented low-energy threshold of 4 keV over the entire detection plane. The CdTe semiconductor detectors of 4 × 4 mm2 size and 1 mm thickness are biased with a high voltage going to − 450 V , and regulated at − 20 ∘ C to minimize the leakage current and maximize the polarization time due to Schottky barrier lowering. The low-energy threshold required for the space mission is achieved thanks to an extensive characterization of the elements constituting the XRDPIX modules. In this paper, we introduce the astrophysical context that led to the design of the mission, with an emphasis on the study of GRBs with ECLAIRs. We provide a detailed description of the XRDPIX hybrid modules, and we explain the experimental setup used for testing and qualifying 45 flight models. We present the results of the measurements performed to validate the module performance with a radioactive source of Americium 241. We study the spectral resolution, the low energy threshold, the gain of the detectors, and their counting performance. We also present two side studies concerning the impact of low temperatures and the stability of the performance over time. To conclude, we propose optimal settings for two key configuration parameters: the high voltage bias and the peaking time, that permit obtaining the challenging 4 keV energy threshold required for the SVOM mission. [ABSTRACT FROM AUTHOR]

Highlights • The paper contains original results about conversion of gravitational waves into electromagnetic waves with the ultra and very high frequency. Abstract The calculations of electromagnetic radiation, caused by a plane gravitational wave propagating in a magnetic dipole fields, have been performed. It is shown that a radiated electromagnetic wave has the frequency of the gravitational wave, and its amplitude is proportional to the square of that frequency. Polarization of the arising electromagnetic wave coincides with the polarization of the gravitational wave. Based on an example of how a gravitational wave propagates in a magnetar’s magnetic dipole field, an evaluation of a conversion coefficient of gravitational waves into electromagnetic waves has been made: the required amplitude of a gravitational wave for on-Earth detection of electromagnetic radiation has been calculated as well. [ABSTRACT FROM AUTHOR]

Abstract POLAR is a compact wide-field space-borne detector for precise measurements of the linear polarisation of hard X-rays emitted from gamma-ray burst and solar flares in the energy range of 50 keV to 500 keV. It consists of a 40 × 40 array of plastic scintillator bars used as a detection material. POLAR was launched into a low Earth orbit on-board the Chinese space-lab TG-2 on September 15, 2016. To achieve high accuracies in polarisation measurements it is essential to perform a precise energy calibration both before and during the flight. Such calibrations are performed with four low activity 22Na radioactive sources placed inside the instrument. Energy conversion factors are related to Compton edge positions from the collinear annihilation photons from the sources. This paper presents the main principles of the in-flight calibration, describes studies of the method based on Monte Carlo simulations and its laboratory verification, and provides some observation results based on the in-flight data analysis. [ABSTRACT FROM AUTHOR]

The new cosmic-ray experiment EMMA operates at the depth of 75 m (50 GeV cutoff energy for vertical muons; 210 m.w.e.) in the Pyhäsalmi mine, Finland. The underground infrastructure consists of a network of eleven stations equipped with multi-layer, position-sensitive detectors. EMMA is designed for cosmic-ray composition studies around the energy range of the knee, i.e., for primary particles with energies between 1 and 10 PeV. In order to yield significant new results EMMA must be able to record data in the full configuration for about three years. The key to the success of the experiment is the performance of its tracking stations. In this paper we describe the layout of EMMA and construction of the two main detector types used for muon tracking: the high-resolution drift chambers and fast scintillation detector arrays. We also show the measured tracking efficiencies, position and angular resolutions, and sensitivity of drift chambers to the air pressure. The measured angular muon distributions are well reproduced by CORSIKA simulations folded with the known density distribution of the overburden. The single muon flux at the depth of 210 m.w.e. is (1.29  ±  0.06) m − 2 s − 1 . This value was determined from the reconstructed tracks registered by a six-layer array of position-sensitive drift chambers. [ABSTRACT FROM AUTHOR]

The positron excess measured by PAMELA and AMS can only be explained if there is one or several sources injecting them. Moreover, at the highest energies, it requires the presence of nearby ( ∼ hundreds of parsecs) and middle age (maximum of  ∼ hundreds of kyr) sources. Pulsars, as factories of electrons and positrons, are one of the proposed candidates to explain the origin of this excess. To calculate the contribution of these sources to the electron and positron flux at the Earth, we developed EDGE (Electron Diffusion and Gamma rays to the Earth), a code to treat the propagation of electrons and compute their diffusion from a central source with a flexible injection spectrum. Using this code, we can derive the source’s gamma-ray spectrum, spatial extension, the all-electron density in space, the electron and positron flux reaching the Earth and the positron fraction measured at the Earth. We present in this paper the foundations of the code and study how different parameters affect the gamma-ray spectrum of a source and the electron flux measured at the Earth. We also studied the effect of several approximations usually performed in these studies. This code has been used to derive the results of the positron flux measured at the Earth in [1]. [ABSTRACT FROM AUTHOR]

A search for tau neutrino induced showers with the MAGIC telescopes is presented. The MAGIC telescopes located at an altitude of 2200 m a.s.l. in the Canary Island of La Palma, can point towards the horizon or a few degrees below across an azimuthal range of about 80°. This provides a possibility to search for air showers induced by tau leptons arising from interactions of tau neutrinos in the Earth crust or the surrounding ocean. In this paper we show how such air showers can be discriminated from the background of very inclined hadronic showers by using Monte Carlo simulations. Taking into account the orography of the site, the point source acceptance and the event rates expected have been calculated for a sample of generic neutrino fluxes from photo-hadronic interactions in AGNs. The analysis of about 30 h of data taken towards the sea leads to a 90% C.L. point source limit for tau neutrinos in the energy range from 1.0 × 10 15 eV to 3.0 × 10 18 eV of about E ν τ 2 × ϕ ( E ν τ ) < 2.0 × 10 − 4 GeV cm − 2 s − 1 for an assumed power-law neutrino spectrum with spectral index γ =−2. However, with 300 h and in case of an optimistic neutrino flare model, limits of the level down to E ν τ 2 × ϕ ( E ν τ ) < 8.4 × 10 − 6 GeV cm − 2 s − 1 can be expected. [ABSTRACT FROM AUTHOR]

Stochastic acceleration of cosmic rays in second order Fermi processes is usually considered too slow to reach ultra-high energies, except in specific cases. In this paper we present the energy spectrum obtained from second order Fermi acceleration in highly turbulent magnetic fields as e.g. found in the outskirts of AGN jets in situations where it can be sufficiently fast to accelerate particles to the highest observed energies. We parametrize the resulting non-power-law spectra and show that these can describe the cosmic ray energy spectrum and mass-composition data at the highest energies if propagation effects are taken into account. [ABSTRACT FROM AUTHOR]

This paper describes the Polarization Spectroscopic Telescope Array ( PolSTAR ), a mission proposed to NASA’s 2014 Small Explorer (SMEX) announcement of opportunity. PolSTAR measures the linear polarization of 3–50 keV (requirement; goal: 2.5–70 keV) X-rays probing the behavior of matter, radiation and the very fabric of spacetime under the extreme conditions close to the event horizons of black holes, as well as in and around magnetars and neutron stars. The PolSTAR design is based on the technology developed for the Nuclear Spectroscopic Telescope Array ( NuSTAR ) mission launched in June 2012. In particular, it uses the same X-ray optics, extendable telescope boom, optical bench, and CdZnTe detectors as NuSTAR . The mission has the sensitivity to measure ∼1% linear polarization fractions for X-ray sources with fluxes down to ∼5 mCrab. This paper describes the PolSTAR design as well as the science drivers and the potential science return. [ABSTRACT FROM AUTHOR]

In this paper are described the ACROPOL and OPD high-altitude stations devoted to characterize the atmospheric radiation fields. The ACROPOL platform, located at the summit of the Pic du Midi in the French Pyrenees at 2885 m above sea level, exploits since May 2011 some scientific equipment, including a BSS neutron spectrometer, detectors based on semiconductor and scintillators. In the framework of a IEAv and ONERA collaboration, a second neutron spectrometer was simultaneously exploited since February 2015 at the summit of the Pico dos Dias in Brazil at 1864 m above the sea level. The both high station platforms allow for investigating the long period dynamics to analyze the spectral variation of cosmic-ray- induced neutron and effects of local and seasonal changes, but also the short term dynamics during solar flare events. This paper presents long and short-term analyses, including measurement and modeling investigations considering the both high altitude stations data. The modeling approach, based on ATMORAD computational platform, was used to link the both station measurements. [ABSTRACT FROM AUTHOR]

Lipari and Stanev developed a method for range fluctuation of high energy muons, stressing the importance of accounting for the fluctuations of the energy loss in radiative processes in 1991 and, now, their method has become the basement for the energy determination of high energy muons through the measurement of the Cherenkov light yields due to those muons in KM3 physics. Once, Takahashi et al. developed a method for the investigation on the depth intensity relation of high energy muons in which all the stochastic processes concerned are taken into account exactly (1983). Now, we make the method by Takahashi et al. revival for the same purpose of the application to the analysis of future KM3 physics. In the present paper, our concern is restricted to the introduction to the fundamental of our method and some subsequent results thereby in which the real simulated behaviors of high energy muons from 10 12 eV to 10 18 eV, the survival probabilities of high energy and so on are included. The discussion around the practical application of our method to the KM3 physics is entrusted in the subsequent papers. As far as the survival probability of high energy muons is concerned, our method gives nearly the same results to Lipari and Stanev’s in some regions and gives the deviated results from theirs in another ones. Thus, we examine the application limit of their method and clarify the reason why, comparing with our method. The most distinct difference in the both methods may become apparent in the treatment on the Cherenkov light yields spectrum by which one may estimate the energies of the muons concerned. We will mention to them in subsequent papers. [ABSTRACT FROM AUTHOR]

The forthcoming decades will see a rapid development of space programs aiming at the implementation of habitats on our satellite. Therefore it makes sense to evaluate the feasibility of a permanent cosmic-ray (CR) observatory on the Moon. Its large sensitive area would allow to carry out a very rich observational program over a time span of a few decades with an unprecedented energy reach. A thorough exploration of the energy region around the CR spectral anomaly located at a few PeV, also known as the "knee", will become possible. In this paper we propose an innovative concept of a modular lunar observatory designed to overcome the limitations of the present generation of cosmic-ray telescopes in Low Earth Orbit. It consists of an array of fully independent modules with limited individual size and weight. This would allow an ample flexibility in the gradual deployment of a progressively larger active volume, while ensuring the collection of meaningful scientific data during the intermediate stages of its implementation. Each independent module consists of three main instruments: a combined Charge and Time-of-Flight detector to identify individual elements from proton to nickel (and beyond), a tracker providing the direction and impact point of the incident particle, and a calorimeter to measure its kinetic energy. The design of each instrument contains innovative solutions that are well within the reach of the present technology. [ABSTRACT FROM AUTHOR]

Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing the traditionally distinct scientific boundaries between astro-particle and atmospheric physics and also requiring understanding of both heliospheric and magnetospheric influences on cosmic rays. Following the paper of Erlykin et al. (2014) we develop further the interpretation of our observed changes in long-wave (LW) radiation, Aplin and Lockwood (2013) by taking account of both cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal structure of the whole atmosphere needs to be considered along with the vertical profile of ionisation. Allowing for, in particular, ionisation by all components of a cosmic ray shower and not just by the muons, reveals that the effect we have detected is certainly not inconsistent with laboratory observations of the LW absorption cross section. The analysis presented here, although very different from that of Erlykin et al., does come to the same conclusion that the events detected by AL were not caused by individual cosmic ray primaries – not because it is impossible on energetic grounds, but because events of the required energy are too infrequent for the 12 h −1 rate at which they were seen by the AL experiment. The present paper numerically models the effect of three different scenario changes to the primary GCR spectrum which all reproduce the required magnitude of the effect observed by AL. However, they cannot solely explain the observed delay in the peak effect which, if confirmed, would appear to open up a whole new and interesting area in the study of water oligomers and their effects on LW radiation. We argue that a technical artefact in the AL experiment is highly unlikely and that our initial observations merit both a wide-ranging follow-up experiment and more rigorous, self-consistent, three-dimensional radiative transfer modelling. [ABSTRACT FROM AUTHOR]

In this paper, we present high-energy neutrino spectra from 21 Galactic supernova remnants (SNRs), derived from gamma-ray measurements in the GeV–TeV range. We find that only the strongest sources, i.e. G40.5-0.5 in the north and Vela Junior in the south could be detected as single point sources by IceCube or KM3NeT, respectively. For the first time, it is also possible to derive a diffuse signal by applying the observed correlation between gamma-ray emission and radio signal. Radio data from 234 supernova remnants listed in Green’s catalog are used to show that the total diffuse neutrino flux is approximately a factor of 2.5 higher compared to the sources that are resolved so far. We show that the signal at above 10 TeV energies can actually become comparable to the diffuse neutrino flux component from interactions in the interstellar medium. Recently, the IceCube collaboration announced the detection of a first diffuse signal of astrophysical high-energy neutrinos. Directional information cannot unambiguously reveal the nature of the sources at this point due to low statistics. A number of events come from close to the Galactic center and one of the main questions is whether at least a part of the signal can be of Galactic nature. In this paper, we show that the diffuse flux from well-resolved SNRs is at least a factor of 20 below the observed flux. [ABSTRACT FROM AUTHOR]

Atmospheric neutrinos are an important background to astrophysical neutrino searches, and are also of considerable interest in their own right. This paper points out that the contribution to conventional atmospheric ν e of the rare semileptonic decay of K S becomes significant at high energy. Although the K S → π e ν branching ratio is very small, the short K S lifetime leads to a high critical energy, so that, for vertical showers, the inclusion of K S semileptonic decay increases the conventional ν e flux by ≈ 30 % at energies above 100 TeV. In this paper, we present calculations of the flux of ν e from K S . At energies above their critical energies, the ν e fluxes from kaon decay may be simply related to the kaon semileptonic widths; this leads to a near-equality between the flux of ν e from K + , K L and K S . [ABSTRACT FROM AUTHOR]

Astroparticle physics and cosmology allow us to scan the universe through multiple messengers. It is the combination of these probes that improves our understanding of the universe, both in its composition and its dynamics. Unlike other areas in science, research in astroparticle physics has a real originality in detection techniques, in infrastructure locations, and in the observed physical phenomenon that is not created directly by humans. It is these features that make the minimisation of statistical and systematic errors a perpetual challenge. In all these projects, the environment is turned into a detector medium or a target. The atmosphere is probably the environment component the most common in astroparticle physics and requires a continuous monitoring of its properties to minimise as much as possible the systematic uncertainties associated. This paper introduces the different atmospheric effects to take into account in astroparticle physics measurements and provides a non-exhaustive list of techniques and instruments to monitor the different elements composing the atmosphere. A discussion on the close link between astroparticle physics and Earth sciences ends this paper. [ABSTRACT FROM AUTHOR]

In the Large High Altitude Air Shower Observatory (LHAASO), one square kilometer array (KM2A), with 5242 electromagnetic particle detectors (EDs) and 1171 muon detectors (MDs), is designed to study ultra-high energy gamma-ray astronomy and cosmic ray physics. The remoteness and numerous detectors extremely demand a robust and automatic calibration procedure. In this paper, a self-calibration method which relies on the measurement of charged particles within the extensive air showers is proposed. The method is fully validated by Monte Carlo simulation and successfully applied in a KM2A prototype array experiment. Experimental results show that the self-calibration method can be used to determine the detector time offset constants at the sub-nanosecond level and the number density of particles collected by each ED with an accuracy of a few percents, which are adequate to meet the physical requirements of LHAASO experiment. This software calibration also offers an ideal method to realtime monitor the detector performances for next generation ground-based EAS experiments covering an area above square kilometers scale. [ABSTRACT FROM AUTHOR]