The High Altitude Detection of Astronomical Radiation(HADAR)experiment is a refracting terrestrial telescope array based on the atmospheric Cherenkov imaging technique.It focuses the Cherenkov light emitted by extensi...The High Altitude Detection of Astronomical Radiation(HADAR)experiment is a refracting terrestrial telescope array based on the atmospheric Cherenkov imaging technique.It focuses the Cherenkov light emitted by extensive air showers through a large aperture water-lens system for observing very-high-energyγ-rays and cosmic rays.With the advantages of a large field-of-view(FOV)and low energy threshold,the HADAR experiment operates in a large-scale sky scanning mode to observe galactic sources.This study presents the prospects of using the HADAR experiment for the sky survey of TeVγ-ray sources from TeVCat and provids a one-year survey of statistical significance.Results from the simulation show that a total of 23 galactic point sources,including five supernova remnant sources and superbubbles,four pulsar wind nebula sources,and 14 unidentified sources,were detected in the HADAR FOV with a significance greater than 5 standard deviations(σ).The statistical significance for the Crab Nebula during one year of operation reached 346.0σand the one-year integral sensitivity of HADAR above 1 TeV was~1.3%–2.4%of the flux from the Crab Nebula.展开更多
The observation of short gamma ray bursts(SGRBs)in the TeV energy range plays an important role in understanding the radiation mechanism and probing potential new physics,such as Lorentz invariance violation(LIV).Howe...The observation of short gamma ray bursts(SGRBs)in the TeV energy range plays an important role in understanding the radiation mechanism and probing potential new physics,such as Lorentz invariance violation(LIV).However,no SGRBs have been observed in this energy range owing to the short duration of SGRBs and the weakness of current experiments.New experiments with new technology are required to detect the very high energy(VHE)emission of SGRBs.In this study,we simulate the VHE γ-ray emissions from SGRBs and calculate the annu-al detection rate with the High Altitude Detection of Astronomical Radiation(HADAR)experiment.First,a set of pseudo-SGRB samples is generated and checked using the observations of the Fermi-GBM,Fermi-LAT,and Swift-BAT measurements.The annual detection rate is calculated from these SGRB samples based on the performance of the HADAR instrument.As a result,the HADAR experiment can detect 0.5 SGRBs per year if the spectral break-off of γ-rays caused by the internal absorption and Klein-Nishina(KN)effect is larger than 100 GeV.For a GRB090510-like GRB in HADAR's view,it should be possible to detect approximately 2000 photons considering the internal absorption and KN effect.With a time delay assumption due to LIV effects,a simulated light curve of GRB090510 has evident energy dependence.We hope that the HADAR experiment can perform SGRB observa-tions and test our calculations in the future.展开更多
The High Altitude Detection of Astronomical Radiation(HADAR)experiment,which was constructed in Xizang,China,combines the wide-angle advantages of traditional EAS array detectors with the high-sensitivity advantages o...The High Altitude Detection of Astronomical Radiation(HADAR)experiment,which was constructed in Xizang,China,combines the wide-angle advantages of traditional EAS array detectors with the high-sensitivity advantages of focused Cherenkov detectors.Its objective is to observe transient sources such as gamma-ray bursts and the counterparts of gravitational waves.This study aims to utilize the latest AI technology to enhance the sensitivity of HADAR experiments.Training datasets and models with distinctive creativity were constructed by incorporating the relevant physical theories for various applications.These models can determine the type,energy,and direction of the incident particles after careful design.We obtained a background identification accuracy of 98.6%,a relative energy reconstruction error of 10.0%,and an angular resolution of 0.22°in a test dataset at 10 TeV.These findings demonstrate the significant potential for enhancing the precision and dependability of detector data analysis in astrophysical research.By using deep learning techniques,the HADAR experiment’s observational sensitivity to the Crab Nebula has surpassed that of MAGIC and H.E.S.S.at energies below 0.5 TeV and remains competitive with conventional narrow-field Cherenkov telescopes at higher energies.In addition,our experiment offers a new approach for dealing with strongly connected,scattered data.展开更多
文摘HADAR(High Altitude Detection of Astronomical Radiation)是一个基于大气切伦科夫成像技术的地面望远镜阵列,其采用大口径折射式水透镜系统来收集大气切伦科夫光,以实现对10 GeV—10 TeV能量段的伽马射线和宇宙线的探测.HADAR具有低阈能和大视场的优势,因此可以对天区进行连续扫描和观测,在观测活动星系核(Active Galactic Nuclei,AGN)等银河系外伽马射线源方面具有明显优势.本文研究了HADAR实验对AGN的探测能力.基于费米望远镜(Fermi Large Area Telescope,Fermi-LAT)的AGN源能谱信息,将观测能量外推至甚高能能段,同时加入河外背景光的吸收效应,以计算HADAR对AGN源观测的统计显著性.研究结果显示,HADAR运行一年时间,预计将有31个Fermi-LAT AGN源以高于5倍显著性被观测到,其中大部分为蝎虎状天体类型.
基金support from the National Natural Science Foundation of China(Nos.11873005,11705103,12005120,12147218,U1831208,U1632104,11875264,and U2031110).
文摘The High Altitude Detection of Astronomical Radiation(HADAR)experiment is a refracting terrestrial telescope array based on the atmospheric Cherenkov imaging technique.It focuses the Cherenkov light emitted by extensive air showers through a large aperture water-lens system for observing very-high-energyγ-rays and cosmic rays.With the advantages of a large field-of-view(FOV)and low energy threshold,the HADAR experiment operates in a large-scale sky scanning mode to observe galactic sources.This study presents the prospects of using the HADAR experiment for the sky survey of TeVγ-ray sources from TeVCat and provids a one-year survey of statistical significance.Results from the simulation show that a total of 23 galactic point sources,including five supernova remnant sources and superbubbles,four pulsar wind nebula sources,and 14 unidentified sources,were detected in the HADAR FOV with a significance greater than 5 standard deviations(σ).The statistical significance for the Crab Nebula during one year of operation reached 346.0σand the one-year integral sensitivity of HADAR above 1 TeV was~1.3%–2.4%of the flux from the Crab Nebula.
基金Supported by the National Natural Science Foundation of China(12263004,12263005,12275279)。
文摘The observation of short gamma ray bursts(SGRBs)in the TeV energy range plays an important role in understanding the radiation mechanism and probing potential new physics,such as Lorentz invariance violation(LIV).However,no SGRBs have been observed in this energy range owing to the short duration of SGRBs and the weakness of current experiments.New experiments with new technology are required to detect the very high energy(VHE)emission of SGRBs.In this study,we simulate the VHE γ-ray emissions from SGRBs and calculate the annu-al detection rate with the High Altitude Detection of Astronomical Radiation(HADAR)experiment.First,a set of pseudo-SGRB samples is generated and checked using the observations of the Fermi-GBM,Fermi-LAT,and Swift-BAT measurements.The annual detection rate is calculated from these SGRB samples based on the performance of the HADAR instrument.As a result,the HADAR experiment can detect 0.5 SGRBs per year if the spectral break-off of γ-rays caused by the internal absorption and Klein-Nishina(KN)effect is larger than 100 GeV.For a GRB090510-like GRB in HADAR's view,it should be possible to detect approximately 2000 photons considering the internal absorption and KN effect.With a time delay assumption due to LIV effects,a simulated light curve of GRB090510 has evident energy dependence.We hope that the HADAR experiment can perform SGRB observa-tions and test our calculations in the future.
文摘The High Altitude Detection of Astronomical Radiation(HADAR)experiment,which was constructed in Xizang,China,combines the wide-angle advantages of traditional EAS array detectors with the high-sensitivity advantages of focused Cherenkov detectors.Its objective is to observe transient sources such as gamma-ray bursts and the counterparts of gravitational waves.This study aims to utilize the latest AI technology to enhance the sensitivity of HADAR experiments.Training datasets and models with distinctive creativity were constructed by incorporating the relevant physical theories for various applications.These models can determine the type,energy,and direction of the incident particles after careful design.We obtained a background identification accuracy of 98.6%,a relative energy reconstruction error of 10.0%,and an angular resolution of 0.22°in a test dataset at 10 TeV.These findings demonstrate the significant potential for enhancing the precision and dependability of detector data analysis in astrophysical research.By using deep learning techniques,the HADAR experiment’s observational sensitivity to the Crab Nebula has surpassed that of MAGIC and H.E.S.S.at energies below 0.5 TeV and remains competitive with conventional narrow-field Cherenkov telescopes at higher energies.In addition,our experiment offers a new approach for dealing with strongly connected,scattered data.
