A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by...A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by the geomagnetic field on these two species were exploited for the particle identification.Application of this method to the simulation of on-orbit electrons/positrons/protons and the real flight data proves that separately measuring the CR positrons/electrons with DAMPE is feasible,though limited by the field of view for the present observation data.Further analysis on the positron flux with this method can be expected in the future.展开更多
We present a new total intensity image of M31 at 1.248 GHz,observed with the Five-hundred-meter Aperture Spherical radio telescope(FAST)with an angular resolution of 4'and a sensitivity of about 16 mK.The new FAST...We present a new total intensity image of M31 at 1.248 GHz,observed with the Five-hundred-meter Aperture Spherical radio telescope(FAST)with an angular resolution of 4'and a sensitivity of about 16 mK.The new FAST image clearly reveals weak emission outside the ring due to its high sensitivity on large-scale structures.We derive a scale length of 2.7 kpc for the cosmic ray electrons and find that the cosmic ray electrons propagate mainly through diffusion by comparing the scale length at 4.8 GHz.The spectral index of the total intensity varies along the ring,which can be attributed to the variation of the spectra of synchrotron emission.This variation is likely caused by the change of star formation rates along the ring.We find that the azimuthal profile of the non-thermal emission can be interpreted by an axisymmetric large-scale magnetic field with varying pitch angle along the ring,indicating a complicated magnetic field configuration in M31.展开更多
A mixed hydrogen and helium（H ＋ He） spectrum with a clear steepening at ~700 TeV has been detected by the ARGO-YBJ experiments. In this paper, we demonstrate that the observed H ＋ He spectrum can be reproduced wel...A mixed hydrogen and helium（H ＋ He） spectrum with a clear steepening at ~700 TeV has been detected by the ARGO-YBJ experiments. In this paper, we demonstrate that the observed H ＋ He spectrum can be reproduced well with a model of cosmic rays escaping from the supernova remnants（SNRs） in our Galaxy. In this model, particles are accelerated in a SNR through a non-linear diffusive shock acceleration mechanism. Three components of high energy light nuclei escaped from the SNR are considered. It should be noted that the proton spectrum observed by KASCADE can be also explained by this model given a higher acceleration efficiency.展开更多
In the following sub-sections,studies of solar-heliospheric effects on cosmic rays,investigating a possible link between cosmic ray flux and Earth’s climate,and detection of MeV-rangeγ-rays from thunderstorms with t...In the following sub-sections,studies of solar-heliospheric effects on cosmic rays,investigating a possible link between cosmic ray flux and Earth’s climate,and detection of MeV-rangeγ-rays from thunderstorms with the data from LHAASO will be discussed;geophysical research with environmental neutrons will be introduced,and some Monte Carlo simulation results about effects of thunderstorm electric fields on LHAASO observations of cosmic rays will be given.展开更多
基金supported by the Outstanding Youth Science Foundation of NSFC(Grant No.12022503)the Joint Funds of the National Natural Science Foundation of China(Grant Nos.U1738208,U1738139,U1738135 and U1738207)+2 种基金the National Natural Science Foundation of China(Grant Nos.11673021,11705197,11773085 and 11851302)the National Key Research and Development Program of China(Grant No.2016YFA0400200)Youth Innovation Promotion Association CAS(Grant No.2021450)。
文摘A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by the geomagnetic field on these two species were exploited for the particle identification.Application of this method to the simulation of on-orbit electrons/positrons/protons and the real flight data proves that separately measuring the CR positrons/electrons with DAMPE is feasible,though limited by the field of view for the present observation data.Further analysis on the positron flux with this method can be expected in the future.
基金supported by the National SKA Program of China(grant No.2022SKA0120101)。
文摘We present a new total intensity image of M31 at 1.248 GHz,observed with the Five-hundred-meter Aperture Spherical radio telescope(FAST)with an angular resolution of 4'and a sensitivity of about 16 mK.The new FAST image clearly reveals weak emission outside the ring due to its high sensitivity on large-scale structures.We derive a scale length of 2.7 kpc for the cosmic ray electrons and find that the cosmic ray electrons propagate mainly through diffusion by comparing the scale length at 4.8 GHz.The spectral index of the total intensity varies along the ring,which can be attributed to the variation of the spectra of synchrotron emission.This variation is likely caused by the change of star formation rates along the ring.We find that the azimuthal profile of the non-thermal emission can be interpreted by an axisymmetric large-scale magnetic field with varying pitch angle along the ring,indicating a complicated magnetic field configuration in M31.
基金Supported by the National Natural Science Foundation of China(11433004,11363006,11103016,11173020)Top Talents Program of Yunnan Province(2015HA030)the Natural Science Foundation of Yunnan Province(2015FB103)
文摘A mixed hydrogen and helium（H ＋ He） spectrum with a clear steepening at ~700 TeV has been detected by the ARGO-YBJ experiments. In this paper, we demonstrate that the observed H ＋ He spectrum can be reproduced well with a model of cosmic rays escaping from the supernova remnants（SNRs） in our Galaxy. In this model, particles are accelerated in a SNR through a non-linear diffusive shock acceleration mechanism. Three components of high energy light nuclei escaped from the SNR are considered. It should be noted that the proton spectrum observed by KASCADE can be also explained by this model given a higher acceleration efficiency.
基金Supported in China by National Natural Science Foundation(NSFC)(12047576,U2031101,11475141)the National Key R&D Program of China(2018YFA0404201,2018YFA0404202)in Thailand by the Thailand Science Research and Innovation(RTA6280002)。
文摘In the following sub-sections,studies of solar-heliospheric effects on cosmic rays,investigating a possible link between cosmic ray flux and Earth’s climate,and detection of MeV-rangeγ-rays from thunderstorms with the data from LHAASO will be discussed;geophysical research with environmental neutrons will be introduced,and some Monte Carlo simulation results about effects of thunderstorm electric fields on LHAASO observations of cosmic rays will be given.
