The Giant Radio Array for Neutrino Detection(GRAND)is a planned large-scale observatory of ultra-high-energy(UHE)cosmic particles,with energies exceeding 10~8 Ge V.Its goal is to solve the long-standing mystery of the...The Giant Radio Array for Neutrino Detection(GRAND)is a planned large-scale observatory of ultra-high-energy(UHE)cosmic particles,with energies exceeding 10~8 Ge V.Its goal is to solve the long-standing mystery of the origin of UHE cosmic rays.To do this,GRAND will detect an unprecedented number of UHE cosmic rays and search for the undiscovered UHE neutrinos and gamma rays associated to them with unmatched sensitivity.GRAND will use large arrays of antennas to detect the radio emission coming from extensive air showers initiated by UHE particles in the atmosphere.Its design is modular:20 separate,independent sub-arrays,each of 10000 radio antennas deployed over 10000 km^2.A staged construction plan will validate key detection techniques while achieving important science goals early.Here we present the science goals,detection strategy,preliminary design,performance goals,and construction plans for GRAND.展开更多
Annual variations of interstellar scintillation can be modelled to constrain parameters of the ionized interstellar medium.If a pulsar is in a binary system,then investigating the orbital parameters is possible throug...Annual variations of interstellar scintillation can be modelled to constrain parameters of the ionized interstellar medium.If a pulsar is in a binary system,then investigating the orbital parameters is possible through analysis of the orbital variation of scintillation.In observations carried out from 2011 to 2020 by the European Pulsar Timing Array radio telescopes,PSRs J0613-0200and J0636+5128 show strong annual variations in their scintillation velocity,while the former additionally exhibits an orbital fluctuation.Bayesian theory and Markov-chain-Monte-Carlo methods are used to interpret these periodic variations.We assume a thin and anisotropic scattering screen model,and discuss the mildly and extremely anisotropic scattering cases.PSR J0613-0200is best described by mildly anisotropic scattering,while PSR J0636+5128 exhibits extremely anisotropic scattering.We measure the distance,velocity,and degree of anisotropy of the scattering screen for our two pulsars,finding that scattering screen distances from Earth for PSRs J0613-0200 and J0636+5128 are 316_(-20)^(+28)pc and 262_(-38)^(+96)pc,respectively.The positions of these scattering screens are coincident with the shell of the Local Bubble towards both pulsars.These associations add to the growing evidence of the Local Bubble shell as a dominant region of scattering along many sightlines.展开更多
基金The GRAND project is supported by the APACHE of the French Agence Nationale de la Recherche(Grant No.ANR-16-CE31-0001)the FranceChina Particle Physics Laboratory,the China Exchange Program from the Royal Netherlands Academy of Arts and Sciences and the Chinese Academy of Sciences+15 种基金the Key Projects of Frontier Science of the Chinese Academy of Sciences(Grant No.QYZDY-SSW-SLH022)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB23000000)the National Key R&D Program of China(Grant No.2018YFA0404601)supported by Sao Paulo Research Foundation(FAPESP)(Grant No.2017/12828-4)partially supported from National Science Foundation(Grant Nos.PHY-1404311,and PHY-1714479)supported by Danish National Research Foundation(DNRF91)Danmarks Grundforskningsfond(Grant No.1041811001)Villum Fonden(Grant No.13164)Washington Carvalho Jr.is supported by Sao Paulo Research Foundation(FAPESP)(Grant No.2015/15735-1)supported by the National Natural Science Foundation of China(Grant No.11375209)supported by the Flemish Foundation for Scientific Research(Grant No.FWO-12L3715N–K.D.de Vries)supported by the Netherlands Organisation for Scientific Research(NWO)supported by the Key Projects of Frontier Science of Chinese Academy of Sciences,(Grant No.QYZDY-SSWSLH022)the Strategic Priority Research Program of Chinese Academy of Sciences,(Grant No.XDB23000000)supported by the National Natural Science Foundation of China(Grant No.11505213)“Data analysis for radio detection array at 21CMA base”
文摘The Giant Radio Array for Neutrino Detection(GRAND)is a planned large-scale observatory of ultra-high-energy(UHE)cosmic particles,with energies exceeding 10~8 Ge V.Its goal is to solve the long-standing mystery of the origin of UHE cosmic rays.To do this,GRAND will detect an unprecedented number of UHE cosmic rays and search for the undiscovered UHE neutrinos and gamma rays associated to them with unmatched sensitivity.GRAND will use large arrays of antennas to detect the radio emission coming from extensive air showers initiated by UHE particles in the atmosphere.Its design is modular:20 separate,independent sub-arrays,each of 10000 radio antennas deployed over 10000 km^2.A staged construction plan will validate key detection techniques while achieving important science goals early.Here we present the science goals,detection strategy,preliminary design,performance goals,and construction plans for GRAND.
基金supported by the National Natural Science Foundation of China(Grant No.12003047)the Major Science and Technology Program of Xinjiang Uygur Autonomous Region(Grant No.2022A03013-2)+2 种基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region(Grant No.2022D01D85)support by the Deutsche Forschungsgemeinschaft(DFG)through the Heisenberg programme(Project No.433075039)financial support from“Programme National de Cosmologie et Galaxies”(PNCG)of CNRS/INSU,France。
文摘Annual variations of interstellar scintillation can be modelled to constrain parameters of the ionized interstellar medium.If a pulsar is in a binary system,then investigating the orbital parameters is possible through analysis of the orbital variation of scintillation.In observations carried out from 2011 to 2020 by the European Pulsar Timing Array radio telescopes,PSRs J0613-0200and J0636+5128 show strong annual variations in their scintillation velocity,while the former additionally exhibits an orbital fluctuation.Bayesian theory and Markov-chain-Monte-Carlo methods are used to interpret these periodic variations.We assume a thin and anisotropic scattering screen model,and discuss the mildly and extremely anisotropic scattering cases.PSR J0613-0200is best described by mildly anisotropic scattering,while PSR J0636+5128 exhibits extremely anisotropic scattering.We measure the distance,velocity,and degree of anisotropy of the scattering screen for our two pulsars,finding that scattering screen distances from Earth for PSRs J0613-0200 and J0636+5128 are 316_(-20)^(+28)pc and 262_(-38)^(+96)pc,respectively.The positions of these scattering screens are coincident with the shell of the Local Bubble towards both pulsars.These associations add to the growing evidence of the Local Bubble shell as a dominant region of scattering along many sightlines.
