P. H. T. Tam
Sun Yat-Sen University
H-index: 56
Asia-China
About P. H. T. Tam
P. H. T. Tam, With an exceptional h-index of 56 and a recent h-index of 33 (since 2020), a distinguished researcher at Sun Yat-Sen University, specializes in the field of High-energy astrophysics.
His recent articles reflect a diverse array of research interests and contributions to the field:
Method to measure muon content of extensive air showers with LHAASO KM2A-WCDA synergy
LHAASO-KM2A detector simulation using Geant4
Does or did the supernova remnant Cassiopeia A operate as a PeVatron?
Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A
The first LHAASO catalog of gamma-ray sources
Evidence of the γ-ray counterpart of nova FM Cir from Fermi–LAT
Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A
Optimization of performance of the KM2A full array using the Crab Nebula
P. H. T. Tam Information
University | Sun Yat-Sen University |
|---|---|
Position | ___ |
Citations(all) | 14786 |
Citations(since 2020) | 4339 |
Cited By | 11601 |
hIndex(all) | 56 |
hIndex(since 2020) | 33 |
i10Index(all) | 133 |
i10Index(since 2020) | 101 |
University Profile Page | Sun Yat-Sen University |
P. H. T. Tam Skills & Research Interests
High-energy astrophysics
Top articles of P. H. T. Tam
Method to measure muon content of extensive air showers with LHAASO KM2A-WCDA synergy
Authors
Zhen Cao,F Aharonian,Q An,LX Bai,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,JT Cai,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,ES Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,SH Chen,SZ Chen,TL Chen,Y Chen,HL Cheng,N Cheng,YD Cheng,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,D della Volpe,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,K Fang,CF Feng,L Feng,SH Feng,XT Feng,YL Feng,B Gao,CD Gao,LQ Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,HH He,HN He,JY He,XB He,Y He,M Heller,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,ZC Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,T Ke,D Kuleshov,K Kurinov,BB Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,HY Li,Jian Li,Jian Li,Jie Li,K Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,H Liu,HD Liu,J Liu,JL Liu,JS Liu,JY Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,WJ Long,R Lu,Q Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,YC Nan,ZW Ou,BY Pang,P Pattarakijwanich,ZY Pei,MY Qi,YQ Qi,BQ Qiao,JJ Qin,D Ruffolo
Journal
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Published Date
2024/2/1
The measurement of shower muons on an event-by-event basis offers a potent tool for conducting ground-based experiments on gamma rays and cosmic rays due to its sensitivity to primary mass and interaction models. In recent years, underground water Cherenkov detectors as large-area muon counters provide the most powerful way of rejecting cosmic ray background when searching for TeV–PeV gamma rays and cosmic ray electrons, an unprecedented rejection power of 1 0 4–1 0 5 is achieved. Unburied water Cherenkov detectors are widely used in ground-based gamma astronomy experiments, eg, Milagro, HAWC, LHAASO-WCDA, etc. However, due to the presence of electromagnetic components, their deployment as event-by-event muon counters has encountered considerable challenges. All the experiments mentioned above reconstruct lateral-distribution-function related parameters to tell a gamma …
LHAASO-KM2A detector simulation using Geant4
Authors
Zhen Cao,F Aharonian,Q An,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,JT Cai,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,SH Chen,SZ Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,K Fang,CF Feng,L Feng,SH Feng,XT Feng,YL Feng,S Gabici,B Gao,CD Gao,LQ Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,HH He,HN He,JY He,XB He,Y He,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,ZC Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,T Ke,D Kuleshov,K Kurinov,BB Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,HY Li,J Li,Jian Li,Jie Li,K Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,J Lin,B Liu,C Liu,D Liu,H Liu,HD Liu,J Liu,JL Liu,JY Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,R Lu,Q Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,ZW Ou,BY Pang,P Pattarakijwanich,ZY Pei,MY Qi,YQ Qi,BQ Qiao,JJ Qin,D Ruffolo
Journal
arXiv preprint arXiv:2404.04801
Published Date
2024/4/7
KM2A is one of the main sub-arrays of LHAASO, working on gamma ray astronomy and cosmic ray physics at energies above 10 TeV. Detector simulation is the important foundation for estimating detector performance and data analysis. It is a big challenge to simulate the KM2A detector in the framework of Geant4 due to the need to track numerous photons from a large number of detector units (>6000) with large altitude difference (30 m) and huge coverage (1.3 km^2). In this paper, the design of the KM2A simulation code G4KM2A based on Geant4 is introduced. The process of G4KM2A is optimized mainly in memory consumption to avoid memory overffow. Some simpliffcations are used to signiffcantly speed up the execution of G4KM2A. The running time is reduced by at least 30 times compared to full detector simulation. The particle distributions and the core/angle resolution comparison between simulation and experimental data of the full KM2A array are also presented, which show good agreement.
Does or did the supernova remnant Cassiopeia A operate as a PeVatron?
Authors
Zhen Cao,F Aharonian,Q An,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,JT Cai,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,SH Chen,SZ Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,D Della Volpe,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,K Fang,CF Feng,L Feng,SH Feng,XT Feng,YL Feng,S Gabici,B Gao,CD Gao,LQ Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,HH He,HN He,JY He,XB He,Y He,M Heller,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,ZC Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,T Ke,D Kuleshov,K Kurinov,BB Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,HY Li,J Li,Jian Li,Jie Li,K Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,H Liu,HD Liu,J Liu,JL Liu,JY Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,R Lu,Q Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,ZW Ou,BY Pang,P Pattarakijwanich,ZY Pei,MY Qi,YQ Qi,BQ Qiao
Journal
The Astrophysical Journal Letters
Published Date
2024/1/30
For decades, supernova remnants (SNRs) have been considered the prime sources of Galactic cosmic rays (CRs). But whether SNRs can accelerate CR protons to PeV energies and thus dominate CR flux up to the knee is currently under intensive theoretical and phenomenological debate. The direct test of the ability of SNRs to operate as CR PeVatrons can be provided by ultrahigh-energy (UHE; Eγ 100 TeV) γ-rays. In this context, the historical SNR Cassiopeia A (Cas A) is considered one of the most promising targets for UHE observations. This paper presents the observation of Cas A and its vicinity by the LHAASO KM2A detector. The exceptional sensitivity of LHAASO KM2A in the UHE band, combined with the young age of Cas A, enabled us to derive stringent modelindependent limits on the energy budget of UHE protons and nuclei accelerated by Cas A at any epoch after the explosion. The results …
Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A
Authors
Zhen Cao,F Aharonian,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,W Bian,AV Bukevich,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,HX Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,S Chen,SH Chen,SZ Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,JH Fang,K Fang,CF Feng,H Feng,L Feng,SH Feng,XT Feng,Y Feng,YL Feng,S Gabici,B Gao,CD Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,M Hasan,HH He,HN He,JY He,Y He,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,I Karpikov,D Kuleshov,K Kurinov,BB Li,CM Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,Jian Li,Jie Li,K Li,SD Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,DB Liu,H Liu,HD Liu,J Liu,JL Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,Q Luo,Y Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,LJ Ou,P Pattarakijwanich,ZY Pei,JC Qi,MY Qi,BQ Qiao
Journal
Physical Review Letters
Published Date
2024/3/26
We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3–30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be− 2.7413±0.0004±0.0050, while above the knee, it is− 3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of− 0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of …
The first LHAASO catalog of gamma-ray sources
Authors
Zhen Cao,F Aharonian,Q An,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,JT Cai,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,SH Chen,SZ Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,D Della Volpe,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,K Fang,CF Feng,L Feng,SH Feng,XT Feng,YL Feng,S Gabici,B Gao,CD Gao,LQ Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,HH He,HN He,JY He,XB He,Y He,M Heller,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,ZC Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,T Ke,D Kuleshov,K Kurinov,BB Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,HY Li,J Li,Jian Li,Jie Li,K Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,H Liu,HD Liu,J Liu,JL Liu,JY Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,R Lu,Q Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,ZW Ou,BY Pang,P Pattarakijwanich,ZY Pei,MY Qi,YQ Qi,BQ Qiao
Journal
The Astrophysical Journal Supplement Series
Published Date
2024/2/27
We present the first catalog of very-high-energy and ultra-high-energy gamma-ray sources detected by the Large High Altitude Air Shower Observatory. The catalog was compiled using 508 days of data collected by the Water Cherenkov Detector Array from 2021 March to 2022 September and 933 days of data recorded by the Kilometer Squared Array from 2020 January to 2022 September. This catalog represents the main result from the most sensitive large coverage gamma-ray survey of the sky above 1 TeV, covering decl. from− 20 to 80. In total, the catalog contains 90 sources with an extended size smaller than 2 and a significance of detection at> 5σ. Based on our source association criteria, 32 new TeV sources are proposed in this study. Among the 90 sources, 43 sources are detected with ultra-high energy (E> 100 TeV) emission at> 4σ significance level. We provide the position, extension, and spectral …
Evidence of the γ-ray counterpart of nova FM Cir from Fermi–LAT
Authors
HH Wang,HD Yan,LC-C Lin,J Takata,PH T Tam
Journal
Monthly Notices of the Royal Astronomical Society: Letters
Published Date
2024/6
We report the results of an analysis of X-ray and γ-ray data from the nova FM Cir taken by Swift and Fermi–LAT. The γ-ray emission from FM Cir can be identified with a significance level of ∼3σ within ∼40 d after the nova eruption (2018 January 19) when we bin the light curve per day. The significance can exceed the 4σ confidence level if we accumulate a longer time (i.e. 20 d) to bin the light curve. The γ-ray counterpart could be identified with a Test Statistic (TS) above 4 until ∼180 d after the eruption. The duration of the γ-ray detection is longer than those reported in previous studies of other novae detected in the GeV range. Significant X-ray emission was observed after the γ-ray flux level fell below the sensitivity limit of Fermi–LAT. The hardness ratio of the X-ray emission decreased rapidly with time, and the spectra were dominated by blackbody radiation from the hot white dwarf. Except for the longer …
Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A
Authors
Zhen Cao,F Aharonian,M Axikegu,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,W Bian,AV Bukevich,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,HX Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,S Chen,SH Chen,SZ Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,M Danzengluobu,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,JH Fang,K Fang,CF Feng,H Feng,L Feng,SH Feng,XT Feng,Y Feng,YL Feng,S Gabici,B Gao,CD Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,M Hasan,HH He,HN He,JY He,Y He,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,I Karpikov,D Kuleshov,K Kurinov,BB Li,CM Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,Jian Li,Jie Li,K Li,SD Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,DB Liu,H Liu,HD Liu,J Liu,JL Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,Q Luo,Y Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,LJ Ou,P Pattarakijwanich,ZY Pei,JC Qi
Published Date
2024/2/21
Very recently, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time GRB 221009A, recording the highest photon statistics in the TeV band ever from a gamma-ray burst. We use this unique observation to place stringent constraints on an energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are times of the Planck energy for the linear, and for the quadratic LIV effects, respectively. Our limits on the quadratic LIV case improve previous best bounds by factors of 5--7.
Optimization of performance of the KM2A full array using the Crab Nebula
Authors
Zhen Cao,F Aharonian,Q An,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,JT Cai,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,SH Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,D della Volpe,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,K Fang,CF Feng,L Feng,SH Feng,XT Feng,YL Feng,S Gabici,B Gao,CD Gao,LQ Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,HH He,HN He,JY He,XB He,Y He,M Heller,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,ZC Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,T Ke,D Kuleshov,K Kurinov,BB Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,HY Li,J Li,Jian Li,Jie Li,K Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,H Liu,HD Liu,J Liu,JL Liu,JY Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,R Lu,Q Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,ZW Ou,BY Pang,P Pattarakijwanich,ZY Pei,MY Qi,YQ Qi,BQ Qiao,JJ Qin
Journal
Chinese Physics C
Published Date
2024/6/1
The full array of the Large High Altitude Air Shower Observatory (LHAASO) has been in operation since July 2021. For its kilometer-square array (KM2A), we have optimized the selection criteria for very high and ultra-high energy γ-rays, using the data collected from August 2021 to August 2022, resulting in an improvement on significance of the detection in the Crab Nebula of about 15
An investigation of the state changes of PSR J2021+ 4026 and the Vela pulsar
Authors
HH Wang,J Takata,L CC Lin,PH T Tam
Journal
Monthly Notices of the Royal Astronomical Society
Published Date
2024/2
We report on long-term evolution of gamma-ray flux and spin-down rate of two bright gamma-ray pulsars, PSR J2021+4026 and Vela (PSR J0835−4510). PSR J2021+4026 shows repeated state changes in gamma-ray flux and spin-down rate. We report two new state changes, a first one from a low gamma-ray flux to a high flux that occurred around MJD 58910, and a second one from high to low flux that occurred around MJD 59510. We find that the flux changes associated with these two state changes are smaller than those determined in the previous events, and the waiting time of the new state change from the high gamma-ray flux to low gamma-ray flux is significantly shorter than previous events. Since the waiting time-scale of the quasi-periodic state changes of PSR J2021+4026 is similar to the waiting time-scale of the glitch events of the Vela pulsar, we search for the state change of the gamma-ray …
GeV γ-ray emission in the field of young massive star cluster RCW 38
Authors
Ting-Ting Ge,Xiao-Na Sun,Rui-Zhi Yang,Pak-Hin Thomas Tam,Ming-Xuan Lu,En-Wei Liang
Journal
Monthly Notices of the Royal Astronomical Society
Published Date
2024/5
We report the detection of γ-ray emission by the Fermi Large Area Telescope towards the young massive star cluster RCW 38 in the 1–500 GeV photon energy range. We found spatially extended GeV emission towards the direction of RCW 38, which is best modelled by a Gaussian disc of 0.23° radius with a significance of the extension of ∼11.4σ. Furthermore, the spatial correlation with the ionized and molecular gas content favours the hadronic origin of the γ-ray emission. The γ-ray spectrum of RCW 38 has a relatively hard photon index of 2.44 ± 0.03, which is similar to other young massive star clusters. We argue that the diffuse GeV γ-ray emission in this region likely originates from the interaction of accelerated protons in the stellar cluster with the ambient gas.
Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A
Authors
Zhen Cao,F Aharonian,Q An,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,JT Cai,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,SH Chen,SZ Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,D Della Volpe,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,K Fang,CF Feng,L Feng,SH Feng,XT Feng,YL Feng,S Gabici,B Gao,CD Gao,LQ Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,HH He,HN He,JY He,XB He,Y He,M Heller,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,ZC Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,T Ke,D Kuleshov,K Kurinov,BB Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,HY Li,J Li,Jian Li,Jie Li,K Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,H Liu,HD Liu,J Liu,JL Liu,JY Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,R Lu,Q Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,ZW Ou,BY Pang,P Pattarakijwanich,ZY Pei,MY Qi,YQ Qi,BQ Qiao
Journal
Physical Review Letters
Published Date
2023/10/9
The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15< l< 12 5,| b|< 5) and outer (125< l< 23 5,| b|< 5) Galactic plane are detected with 29.1 σ and 12.7 σ significance, respectively. The outer Galactic plane diffuse emission is detected for the first time in the very-to ultra-high-energy domain (E> 10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of− 2.99±0.04, which is different from the curved spectrum as expected …
Multiwavelength study of the galactic PeVatron candidate LHAASO J2108+ 5157
Authors
S Abe,A Aguasca-Cabot,I Agudo,N Alvarez Crespo,LA Antonelli,C Aramo,A Arbet-Engels,M Artero,K Asano,P Aubert,A Baktash,A Bamba,A Baquero Larriva,L Baroncelli,U Barres De Almeida,JA Barrio,I Batkovic,J Baxter,J Becerra González,E Bernardini,MI Bernardos,J Bernete Medrano,A Berti,P Bhattacharjee,N Biederbeck,C Bigongiari,E Bissaldi,O Blanch,P Bordas,C Buisson,A Bulgarelli,I Burelli,M Buscemi,M Cardillo,S Caroff,A Carosi,F Cassol,D Cauz,G Ceribella,Y Chai,K Cheng,A Chiavassa,M Chikawa,L Chytka,A Cifuentes,JL Contreras,J Cortina,H Costantini,G D’Amico,M Dalchenko,A De Angelis,M De Bony De Lavergne,B De Lotto,R De Menezes,G Deleglise,C Delgado,J Delgado Mengual,D Della Volpe,M Dellaiera,A Di Piano,F Di Pierro,R Di Tria,L Di Venere,C Díaz,RM Dominik,D Dominis Prester,A Donini,D Dorner,M Doro,D Elsässer,G Emery,J Escudero,V Fallah Ramazani,G Ferrara,A Fiasson,L Freixas Coromina,S Fröse,S Fukami,Y Fukazawa,E Garcia,R Garcia López,D Gasparrini,D Geyer,J Giesbrecht Paiva,N Giglietto,F Giordano,E Giro,P Gliwny,N Godinovic,R Grau,D Green,J Green,S Gunji,J Hackfeld,D Hadasch,A Hahn,K Hashiyama,T Hassan,K Hayashi,L Heckmann,M Heller,J Herrera Llorente,K Hirotani,D Hoffmann,D Horns,J Houles,M Hrabovsky,D Hrupec,D Hui,M Hütten,R Imazawa,T Inada,Y Inome,K Ioka,M Iori,K Ishio,Y Iwamura,M Jacquemont,I Jimenez Martinez,J Jurysek,M Kagaya,V Karas,H Katagiri,J Kataoka,D Kerszberg,Y Kobayashi,A Kong,H Kubo,J Kushida,M Lainez,G Lamanna,A Lamastra,T Le Flour,M Linhoff,F Longo,R López-Coto,M López-Moya,A López-Oramas,S Loporchio,A Lorini,PL Luque-Escamilla,P Majumdar,M Makariev,D Mandat,M Manganaro,G Manicò,K Mannheim,M Mariotti,P Marquez,G Marsella
Journal
Astronomy & astrophysics
Published Date
2023/5/1
Context Several new ultrahigh-energy (UHE) γ-ray sources have recently been discovered by the Large High Altitude Air Shower Observatory (LHAASO) collaboration. These represent a step forward in the search for the so-called Galactic PeVatrons, the enigmatic sources of the Galactic cosmic rays up to PeV energies. However, it has been shown that multi-TeV γ-ray emission does not necessarily prove the existence of a hadronic accelerator in the source; indeed this emission could also be explained as inverse Compton scattering from electrons in a radiation-dominated environment. A clear distinction between the two major emission mechanisms would only be made possible by taking into account multi-wavelength data and detailed morphology of the source.Aims We aim to understand the nature of the unidentified source LHAASO J2108+5157, which is one of the few known UHE sources with no very high …
Pointing calibration of LHAASO-WFCTA telescopes using bright stars
Authors
Zhen Cao,F Aharonian,Q An,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,JT Cai,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,SH Chen,SZ Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,D Della Volpe,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,K Fang,CF Feng,L Feng,SH Feng,XT Feng,YL Feng,S Gabici,B Gao,CD Gao,LQ Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,HH He,HN He,JY He,XB He,Y He,M Heller,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,ZC Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,T Ke,D Kuleshov,K Kurinov,BB Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,HY Li,Jian Li,Jian Li,Jie Li,K Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,H Liu,HD Liu,J Liu,JL Liu,JY Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,R Lu,Q Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,ZW Ou,BY Pang,P Pattarakijwanich,ZY Pei,MY Qi,YQ Qi,BQ Qiao
Journal
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Published Date
2023/11/1
One of the main scientific objectives of the Large High Altitude Air Shower Observatory (LHAASO) is to perform accurate measurements of the energy spectra for different cosmic ray masses, from a few TeV to 100 PeV. As one of the main sub-arrays of LHAASO, the Wide Field-of-View Cherenkov Telescope Array (WFCTA), which consists of 18 telescopes, can help in achieving this goal. The pointing accuracy of each telescope is crucial for reconstructing energy and determining mass-sensitive parameters. In this study, a method for absolute pointing calibration using ultraviolet bright stars was established. The proposed method can achieve a pointing accuracy of approximately 0.02° by using more than five stars. When more stars are used in the telescope’s field of view, the accuracy of the pointing calibration can be improved, e.g, a pointing accuracy of 0.01° can be achieved when using more than 15 stars. A high …
Sensitivity of the Cherenkov Telescope Array to spectral signatures of hadronic PeVatrons with application to Galactic Supernova Remnants
Authors
Fabio Acero,A Acharyya,R Adam,A Aguasca-Cabot,Ivan Agudo,A Aguirre-Santaella,J Alfaro,Roberto Aloisio,N Álvarez Crespo,R Alves Batista,Lorenzo Amati,Elena Amato,Giovanni Ambrosi,EO Angüner,Carla Aramo,C Arcaro,T Armstrong,K Asano,Y Ascasibar,J Aschersleben,M Backes,A Baktash,Csaba Balazs,Matteo Balbo,Jean Ballet,A Baquero Larriva,V Barbosa Martins,U Barres de Almeida,Juan A Barrio,Denis Bastieri,JR Baxter,J Becker Tjus,W Benbow,Maria I Bernardos-Martin,J Bernete,Alessio Berti,Bruna Bertucci,V Beshley,Pooja Bhattacharjee,Saptashwa Bhattacharyya,A Biland,Elisabetta Bissaldi,J Biteau,Oscar Blanch,Pol Bordas,E Bottacini,Johan Bregeon,Robert Brose,N Bucciantini,A Bulgarelli,M Capasso,RA Capuzzo Dolcetta,P Caraveo,M Cardillo,R Carosi,S Casanova,E Cascone,F Cassol,F Catalani,M Cerruti,P Chadwick,S Chaty,A Chen,M Chernyakova,A Chiavassa,J Chudoba,C Coimbra-Araujo,V Conforti,JL Contreras,A Costa,H Costantini,P Cristofari,R Crocker,G D’amico,F D’ammando,A De Angelis,V De Caprio,EM de Gouveia Dal Pino,E de Ona Wilhelmi,V de Souza,C Delgado,D Della Volpe,D Depaoli,T Di Girolamo,F Di Pierro,R Di Tria,L Di Venere,S Diebold,JI Djuvsland,A Donini,M Doro,RDC Dos Anjos,VV Dwarkadas,S Einecke,D Elsässer,G Emery,C Evoli,D Falceta-Goncalves,E Fedorova,S Fegan,G Ferrand,E Fiandrini,M Filipovic,V Fioretti,M Fiori,L Foffano,G Fontaine,S Fukami,G Galanti,G Galaz,V Gammaldi,C Gasbarra,A Ghalumyan,G Ghirlanda,M Giarrusso,G Giavitto,N Giglietto,F Giordano,M Giroletti,A Giuliani,L Giunti,N Godinovic,J Goulart Coelho,L Gréaux,D Green,M-H Grondin,O Gueta,S Gunji,T Hassan,M Heller,S Hernández-Cadena,J Hinton,B Hnatyk,R Hnatyk,D Hoffmann,W Hofmann,J Holder,D Horan,P Horvath,M Hrabovsky,D Hrupec,T Inada,F Incardona,S Inoue,K Ishio,Marek Jamrozy,P Janecek,I Jiménez Martínez,W Jin,I Jung-Richardt
Journal
Astroparticle Physics
Published Date
2023/8/1
Abstract The local Cosmic Ray (CR) energy spectrum exhibits a spectral softening at energies around 3 PeV. Sources which are capable of accelerating hadrons to such energies are called hadronic PeVatrons. However, hadronic PeVatrons have not yet been firmly identified within the Galaxy. Several source classes, including Galactic Supernova Remnants (SNRs), have been proposed as PeVatron candidates. The potential to search for hadronic PeVatrons with the Cherenkov Telescope Array (CTA) is assessed. The focus is on the usage of very high energy γ-ray spectral signatures for the identification of PeVatrons. Assuming that SNRs can accelerate CRs up to knee energies, the number of Galactic SNRs which can be identified as PeVatrons with CTA is estimated within a model for the evolution of SNRs. Additionally, the potential of a follow-up observation strategy under moonlight conditions for PeVatron …
Explaining the Hardening Structures of Helium Spectrum and Boron to Carbon Ratio through Different Propagation Models
Authors
Qing Luo,Jie Feng,Pak-Hin Thomas Tam
Journal
Galaxies
Published Date
2023/3/8
Recently, a series of high-precision measurements by various experiments show that cosmic ray nuclei spectra begin to harden at ∼200 GV and the boron-to-carbon (B/C) ratio has a similar trend around the same energy. These anomalous structures possibly result from the journey of cosmic rays (CRs) from their sources to our solar system, which has important implications for our understanding of the origin and propagation of Galactic cosmic rays (GCRs). In this work, we investigate several propagation models and attempt to explain these anomalous observations. We have verified that an extension of the traditional propagation model taking into account spatially dependent propagation and secondary particle acceleration provides a more accurate description of the latest B/C ratio and the Helium flux data measured by DAMPE, CALET, and AMS-02.
Influences of dynamical disruptions on the evolution of pulsars in globular clusters
Authors
Kwangmin Oh,CY Hui,Jongsuk Hong,J Takata,AKH Kong,Pak-Hin Thomas Tam,Kwan-Lok Li,KS Cheng
Journal
Monthly Notices of the Royal Astronomical Society
Published Date
2023/11
By comparing the physical properties of pulsars hosted by core-collapsed (CCed) and non-core-collapsed (non-CCed) globular clusters (GCs), we find that pulsars in CCed GCs rotate significantly slower than their counterparts in non-CCed GCs. Additionally, radio luminosities at 1.4 GHz in CCed GCs are higher. These findings are consistent with the scenario that dynamical interactions in GCs can interrupt angular momentum transfer processes and surface magnetic field decay during the recycling phase. Our results suggest that such effects in CCed GCs are stronger due to more frequent disruptions of compact binaries. This is further supported by the observation that both estimated disruption rates and the fraction of isolated pulsars are predominantly higher in CCed GCs.
A Number Estimate of Detectable Detached Black Hole-star Binaries using a Photometric Telescope
Authors
Zhe-Cheng Hu,Yan-Lv Yang,Yuan-Hao Wen,Rong-Feng Shen,Pak-Hin Thomas Tam
Journal
Research in Astronomy and Astrophysics
Published Date
2023/7/10
Detached and wide-orbit black hole-star binaries (BHSBs) can generate three types of periodic photometric signals: Ellipsoidal Variation, Doppler beaming and Self-Lensing (SL), providing a proxy to discover these black holes. We estimate the relative amplitude of the three signals for such systems and the detectability for black holes of a photometric telescope like Kepler in several steps. We estimate the searchable star number by assuming every star has a black hole companion, and apply the occurrence of BHSBs in field stars to estimate the detectable black hole signals. We consider three types of Initial Mass Function (IMF) model with different high end exponential slopes." When spot and white noise are both considered, there is about one detectable signal for SL and less than one event is expected for beaming and Ellipsoidal Variation signal in Kepler Input Catalog stars with the standard IMF model. †to †…
A comparison of millisecond pulsar populations between globular clusters and the Galactic field
Authors
Jongsu Lee,CY Hui,J Takata,AKH Kong,Pak-Hin Thomas Tam,Kwan-Lok Li,KS Cheng
Journal
The Astrophysical Journal
Published Date
2023/2/28
We have performed a systematic study of the rotational, orbital, and X-ray properties of millisecond pulsars (MSPs) in globular clusters (GCs) and compared their nature with those of the MSPs in the Galactic field (GF). We found that GC MSPs generally rotate slower than their counterparts in the GF. Different from the expectation of a simple recycling scenario, no evidence for the correlation between the orbital period and the rotation period can be found in the MSP binaries in GCs. There is also an indication that the surface magnetic field of GC MSPs is stronger than those in the GF. All these suggest dynamical interactions in GCs can alter the evolution of MSPs/their progenitors, which can leave an imprint on their X-ray emission properties. While the MSPs in both GF and GCs have similar distributions of X-ray luminosity and hardness, our sample supports the notion that these two populations follow different …
An Ultrahigh-energy -ray Bubble Powered by a Super PeVatron
Authors
Zhen Cao,F Aharonian,Q An,M Axikegu,YX Bai,YW Bao,D Bastieri,XJ Bi,YJ Bi,JT Cai,Q Cao,WY Cao,Zhe Cao,J Chang,JF Chang,AM Chen,ES Chen,Liang Chen,Lin Chen,Long Chen,MJ Chen,ML Chen,QH Chen,SH Chen,SZ Chen,TL Chen,Y Chen,N Cheng,YD Cheng,MY Cui,SW Cui,XH Cui,YD Cui,BZ Dai,HL Dai,ZG Dai,M Danzengluobu,D Della Volpe,XQ Dong,KK Duan,JH Fan,YZ Fan,J Fang,K Fang,CF Feng,L Feng,SH Feng,XT Feng,YL Feng,S Gabici,B Gao,CD Gao,LQ Gao,Q Gao,W Gao,WK Gao,MM Ge,LS Geng,G Giacinti,GH Gong,QB Gou,MH Gu,FL Guo,XL Guo,YQ Guo,YY Guo,YA Han,HH He,HN He,JY He,XB He,Y He,M Heller,YK Hor,BW Hou,C Hou,X Hou,HB Hu,Q Hu,SC Hu,DH Huang,TQ Huang,WJ Huang,XT Huang,XY Huang,Y Huang,ZC Huang,XL Ji,HY Jia,K Jia,K Jiang,XW Jiang,ZJ Jiang,M Jin,MM Kang,T Ke,D Kuleshov,K Kurinov,BB Li,Cheng Li,Cong Li,D Li,F Li,HB Li,HC Li,HY Li,Jie Li,Jian Li,Jie Li,K Li,WL Li,XR Li,Xin Li,YZ Li,Zhe Li,Zhuo Li,EW Liang,YF Liang,SJ Lin,B Liu,C Liu,D Liu,H Liu,HD Liu,J Liu,JL Liu,JY Liu,MY Liu,RY Liu,SM Liu,W Liu,Y Liu,YN Liu,R Lu,Q Luo,HK Lv,BQ Ma,LL Ma,XH Ma,JR Mao,Z Min,W Mitthumsiri,HJ Mu,YC Nan,A Neronov,ZW Ou,BY Pang,P Pattarakijwanich,ZY Pei,MY Qi
Published Date
2023/10/31
We report the detection of a -ray bubble spanning at least 100 in ultra high energy (UHE) up to a few PeV in the direction of the star-forming region Cygnus X, implying the presence Super PeVatron(s) accelerating protons to at least 10 PeV. A log-parabola form with the photon index $\Gamma (E) = (2.71 \pm 0.02) + (0.11 \pm 0.02) \times \log_{10} (E/10 \ {\rm TeV})$ is found fitting the gamma-ray energy spectrum of the bubble well. UHE sources, `hot spots' correlated with very massive molecular clouds, and a quasi-spherical amorphous -ray emitter with a sharp central brightening are observed in the bubble. In the core of , spatially associating with a region containing massive OB association (Cygnus OB2) and a microquasar (Cygnus X-3), as well as previously reported multi-TeV sources, an enhanced concentration of UHE -rays are observed with 2 photons at energies above 1 PeV. The general feature of the bubble, the morphology and the energy spectrum, are reasonably reproduced by the assumption of a particle accelerator in the core, continuously injecting protons into the ambient medium.
Performance of the joint LST-1 and MAGIC observations evaluated with Crab Nebula data
Authors
H Abe,K Abe,S Abe,VA Acciari,A Aguasca-Cabot,I Agudo,N Alvarez Crespo,T Aniello,S Ansoldi,LA Antonelli,C Aramo,A Arbet-Engels,C Arcaro,M Artero,K Asano,P Aubert,D Baack,A Babić,A Baktash,A Bamba,A Baquero Larriva,L Baroncelli,U Barres De Almeida,JA Barrio,I Batković,J Baxter,J Becerra González,W Bednarek,E Bernardini,MI Bernardos,J Bernete Medrano,A Berti,J Besenrieder,P Bhattacharjee,N Biederbeck,C Bigongiari,A Biland,E Bissaldi,O Blanch,G Bonnoli,P Bordas,Ž Bošnjak,A Bulgarelli,I Burelli,L Burmistrov,M Buscemi,G Busetto,A Campoy Ordaz,M Cardillo,S Caroff,A Carosi,R Carosi,MS Carrasco,M Carretero-Castrillo,F Cassol,AJ Castro-Tirado,D Cauz,D Cerasole,G Ceribella,Y Chai,K Cheng,A Chiavassa,M Chikawa,L Chytka,A Cifuentes,S Cikota,E Colombo,JL Contreras,A Cornelia,J Cortina,H Costantini,S Covino,Giacomo D’Amico,V D’Elia,P Da Vela,M Dalchenko,F Dazzi,Angelis De Angelis,M de Bony de Lavergne,B De Lotto,M De Lucia,R De Menezes,L Del Peral,A Del Popolo,G Deleglise,M Delfino,C Delgado Mendez,J Delgado Mengual,D Della Volpe,M Dellaiera,D Depaoli,A Di Piano,F Di Pierro,A Di Pilato,R Di Tria,L Di Venere,RM Dominik,D Dominis Prester,A Donini,D Dorner,M Doro,C Díaz,L Eisenberger,D Elsässer,G Emery,J Escudero,V Fallah Ramazani,L Fariña,A Fattorini,G Ferrara,F Ferrarotto,A Fiasson,L Foffano,L Font,L Freixas Coromina,S Fröse,S Fukami,Y Fukazawa,RJ Garcia López,E Garcia,M Garczarczyk,RJ García López,C Gasbarra,D Gasparrini,S Gasparyan,M Gaug,D Geyer,JG Giesbrecht Paiva,N Giglietto,F Giordano,P Gliwny,N Godinović,R Grau,D Green,JG Green,S Gunji,P Günther,J Hackfeld,D Hadasch,A Hahn,K Hashiyama,T Hassan,K Hayashi,L Heckmann,M Heller,J Herrera Llorente,K Hirotani,D Hoffmann,D Horns,J Houles
Journal
Astronomy & astrophysics
Published Date
2023/12/1
Aims Large-Sized Telescope 1 (LST-1), the prototype for the Large-Sized Telescope at the upcoming Cherenkov Telescope Array Observatory, is concluding its commissioning phase at the Observatorio del Roque de los Muchachos on the island of La Palma. The proximity of LST-1 to the two MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes makes it possible to carry out observations of the same gamma-ray events with both systems.Methods We describe the joint LST-1+MAGIC analysis pipeline and used simultaneous Crab Nebula observations and Monte Carlo simulations to assess the performance of the three-telescope system. The addition of the LST-1 telescope allows for the recovery of events in which one of the MAGIC images is too dim to survive analysis quality cuts.Results Thanks to the resulting increase in the collection area and stronger background rejection, we found a significant …
P. H. T. Tam FAQs
What is P. H. T. Tam's h-index at Sun Yat-Sen University?
The h-index of P. H. T. Tam has been 33 since 2020 and 56 in total.
What are P. H. T. Tam's top articles?
The articles with the titles of
Method to measure muon content of extensive air showers with LHAASO KM2A-WCDA synergy
LHAASO-KM2A detector simulation using Geant4
Does or did the supernova remnant Cassiopeia A operate as a PeVatron?
Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A
The first LHAASO catalog of gamma-ray sources
Evidence of the γ-ray counterpart of nova FM Cir from Fermi–LAT
Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A
Optimization of performance of the KM2A full array using the Crab Nebula
...
are the top articles of P. H. T. Tam at Sun Yat-Sen University.
What are P. H. T. Tam's research interests?
The research interests of P. H. T. Tam are: High-energy astrophysics
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P. H. T. Tam has 14,786 citations in total.
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