Author: "Zhang, H.-M." - Searchworks@Jio Institute Digital Library Search Results

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1,354 results on '"Zhang, H.-M."'

1. Detection of two TeV gamma-ray outbursts from NGC 1275 by LHAASO

Author: Cao, Zhen, Aharonian, F., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo., X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The Water Cherenkov Detector Array (WCDA) is one of the components of Large High Altitude Air Shower Observatory (LHAASO) and can monitor any sources over two-thirds of the sky for up to 7 hours per day with >98\% duty cycle. In this work, we report the detection of two outbursts of the Fanaroff-Riley I radio galaxy NGC 1275 that were detected by LHAASO-WCDA between November 2022 and January 2023 with statistical significance of 5.2~$\sigma$ and 8.3~$\sigma$. The observed spectral energy distribution in the range from 500 GeV to 3 TeV is fitted by a power-law with a best-fit spectral index of $\alpha=-3.37\pm0.52$ and $-3.35\pm0.29$, respectively. The outburst flux above 0.5~TeV was ($4.55\pm 4.21)\times~10^{-11}~\rm cm^{-2}~s^{-1}$ and ($3.45\pm 1.78)\times~10^{-11}~\rm cm^{-2}~s^{-1}$, corresponding to 60\%, 45\% of Crab Nebula flux. Variation analysis reveals the variability time-scale of days at the TeV energy band. A simple test by one-zone synchrotron self-Compton model reproduces the data in the gamma-ray band well., Comment: 11 pages, 8 figures, 3 tables
Published: 2024

2. LHAASO detection of very-high-energy gamma-ray emission surrounding PSR J0248+6021

Author: Cao, Zhen, Aharonian, F., An, Q., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, J. H., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., Zou, Y. C., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report the detection of an extended very-high-energy (VHE) gamma-ray source coincident with the locations of middle-aged (62.4~\rm kyr) pulsar PSR J0248+6021, by using the LHAASO-WCDA data of live 796 days and LHAASO-KM2A data of live 1216 days. A significant excess of \gray induced showers is observed both by WCDA in energy bands of 1-25~\rm TeV and KM2A in energy bands of $>$ 25~\rm TeV with 7.3 $\sigma$ and 13.5 $\sigma$, respectively. The best-fit position derived through WCDA data is R.A. = 42.06$^\circ \pm$ 0.12$^\circ$ and Dec. = 60.24$^\circ \pm $ 0.13$^\circ$ with an extension of 0.69$^\circ\pm$0.15$^\circ$ and that of the KM2A data is R.A.= 42.29$^\circ \pm $ 0.13$^\circ$ and Dec. = 60.38$^\circ \pm$ 0.07$^\circ$ with an extension of 0.37$^\circ\pm$0.07$^\circ$. No clear extended multiwavelength counterpart of this LHAASO source has been found from the radio band to the GeV band. The most plausible explanation of the VHE \gray emission is the inverse Compton process of highly relativistic electrons and positrons injected by the pulsar. These electrons/positrons are hypothesized to be either confined within the pulsar wind nebula or to have already escaped into the interstellar medium, forming a pulsar halo., Comment: 12 pages, 10 figures, Accepted by Sci. China-Phys. Mech. Astron
Published: 2024

3. Constraints on Ultra Heavy Dark Matter Properties from Dwarf Spheroidal Galaxies with LHAASO Observations

Author: Cao, Zhen, Aharonian, F., An, Q., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Saiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology
Abstract: In this work we try to search for signals generated by ultra-heavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible gamma-ray by dark matter annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter which have low fluxes of astrophysical $\gamma$-ray background while large amount of dark matter. By analyzing more than 700 days observational data at LHAASO, no significant dark matter signal from 1 TeV to 1 EeV is detected. Accordingly we derive the most stringent constraints on the ultra-heavy dark matter annihilation cross-section up to EeV. The constraints on the lifetime of dark matter in decay mode are also derived., Comment: 17 pages, 12 figures, accepted by PRL
Published: 2024

4. Data quality control system and long-term performance monitor of the LHAASO-KM2A

Author: Cao, Zhen, Aharonian, F., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Bian, W., Bukevich, A. V., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, H. X., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, J. H., Fang, K., Feng, C. F., Feng, H., Feng, L., Feng, S. H., Feng, X. T., Feng, Y., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., Hasan, M., He, H. H., He, H. N., He, J. Y., He, Y., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Karpikov, I., Kuleshov, D., Kurinov, K., Li, B. B., Li, C. M., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, Jian, Li, Jie, Li, K., Li, S. D., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, D. B., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Luo, Q., Luo, Y., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, L. J., Pattarakijwanich, P., Pei, Z. Y., Qi, J. C., Qi, M. Y., Qiao, B. Q., Qin, J. J., Raza, A., Ruffolo, D., Sáiz, A., Saeed, M., Semikoz, D., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, D. X., Sun, Q. N., Sun, X. N., Sun, Z. B., Takata, J., Tam, P. H. T., Tang, Q. W., Tang, R., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, Kai, Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, Q. W., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, Y. L., Xing, Y., Xiong, D. R., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, C. Y., Yang, F., Yang, F. F., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, W. X., Yao, Y. H., Yao, Z. G., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zhao, X. H., Zheng, F., Zhong, W. J., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, B. Y., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., Zou, Y. C., and Zuo, X.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: 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. This information is used for physical analysis in gamma-ray astronomy and cosmic ray physics. 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. According to the observation of the Crab Nebula at energies from 25 TeV to 100 TeV, the time averaged pointing errors are estimated to be $-0.003^{\circ} \pm 0.005^{\circ}$ and $0.001^{\circ} \pm 0.006^{\circ}$ in the R.A. and Dec directions, respectively., Comment: 15 pages, 9 figures
Published: 2024

5. Discovery of Very-high-energy Gamma-ray Emissions from the Low Luminosity AGN NGC 4278 by LHAASO

Author: Cao, Zhen, Aharonian, F., An, Q., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, J. H., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., Zou, Y. C., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The first source catalog of Large High Altitude Air Shower Observatory reported the detection of a very-high-energy gamma ray source, 1LHAASO J1219+2915. In this paper a further detailed study of the spectral and temporal behavior of this point-like source have been carried. The best-fit position of the TeV source ($\rm{RA}=185.05^{\circ}\pm0.04^{\circ}$, $\rm{Dec}=29.25^{\circ}\pm0.03^{\circ}$) is compatible with NGC 4278 within $\sim0.03$ degree. Variation analysis shows an indication of the variability at a few months level in the TeV band, which is consistent with low frequency observations. Based on these observations, we report the detection of TeV $\gamma$-ray emissions from this low-luminosity AGN NGC 4278. The observations by LHAASO-WCDA during active period has a significance level of 8.8\,$\sigma$ with best-fit photon spectral index $\varGamma=2.56\pm0.14$ and a flux $f_{1-10\,\rm{TeV}}=(7.0\pm1.1_{\rm{sta}}\pm0.35_{\rm{syst}})\times10^{-13}\,\rm{photons\,cm^{-2}\,s^{-1}}$, or approximately $5\%$ of the Crab Nebula. The discovery of VHE from NGC 4278 indicates that the compact, weak radio jet can efficiently accelerate particles and emit TeV photons., Comment: 11 pages, 5 figures
Published: 2024

6. LHAASO-KM2A detector simulation using Geant4

Author: Cao, Zhen, Aharonian, F., An, Q., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, J. H., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: 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.
Published: 2024
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7. Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

Author: The LHAASO Collaboration, Cao, Zhen, Aharonian, F., An, Q., Axikegu, A., Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: 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 $3.67 \pm 0.05 \pm 0.15$ PeV. Below the knee, the spectral index is found to be -$2.7413 \pm 0.0004 \pm 0.0050$, while above the knee, it is -$3.128 \pm 0.005 \pm 0.027$, 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 -$0.1200 \pm 0.0003 \pm 0.0341$. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components., Comment: 8 pages, 3 figures
Published: 2024
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8. Does or did the supernova remnant Cassiopeia A operate as a PeVatron?

Author: Cao, Zhen, Aharonian, F., An, Q., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo., X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: 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; $E_\gamma \geq 100$~TeV) $\gamma$-rays. In this context, the historical SNR Cassiopeia A (Cas A) is considered one of the most promising target 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 model-independent limits on the energy budget of UHE protons and nuclei accelerated by Cas A at any epoch after the explosion. The results challenge the prevailing paradigm that Cas A-type SNRs are major suppliers of PeV CRs in the Milky Way., Comment: 11 pages, 3 figures, Accepted by the APJL
Published: 2023

9. Very high energy gamma-ray emission beyond 10 TeV from GRB 221009A

Author: Cao, Zhen, Aharonian, F., An, Q., Axikegu, A., Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The highest energy gamma-rays from gamma-ray bursts (GRBs) have important implications for their radiation mechanism. Here we report for the first time the detection of gamma-rays up to 13 TeV from the brightest GRB 221009A by the Large High Altitude Air-shower Observatory (LHAASO). The LHAASO-KM2A detector registered more than 140 gamma-rays with energies above 3 TeV during 230$-$900s after the trigger. The intrinsic energy spectrum of gamma-rays can be described by a power-law after correcting for extragalactic background light (EBL) absorption. Such a hard spectrum challenges the synchrotron self-Compton (SSC) scenario of relativistic electrons for the afterglow emission above several TeV. Observations of gamma-rays up to 13 TeV from a source with a measured redshift of z=0.151 hints more transparency in intergalactic space than previously expected. Alternatively, one may invoke new physics such as Lorentz Invariance Violation (LIV) or an axion origin of very high energy (VHE) signals., Comment: 49pages, 11figures
Published: 2023
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10. Evidence of mini-jet emission in a large emission zone from a magnetically-dominated gamma-ray burst jet

Author: Yi, S. -X., Wang, C. -W., Shao, X. -Y., Moradi, R., Gao, H., Zhang, B., Xiong, S. -L., Zhang, S. -N., Tan, W. -J., Liu, J. -C., Xue, W. -C., Zhang, Y. -Q., Zheng, C., Wang, Y., Zhang, P., An, Z. -H., Cai, C., Feng, P. -Y., Gong, K., Guo, D. -Y., Huang, Y., Li, B., Li, X. -B., Li, X. -Q., Liu, X. -J., Liu, Y. -Q., Ma, X., Peng, W. -X., Qiao, R., Song, L. -M., Wang, J., Wang, P., Wen, X. -Y., Xiao, S., Xu, Y. -B., Yang, S., Yi, Q. -B., Zhang, D. -L., Zhang, F., Zhang, H. -M., Zhang, J. -P., Zhang, Z., Zhao, X. -Y., Zhao, Y., and Zheng, S. -J.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The second brightest GRB in history, GRB230307A provides an ideal laboratory to study the details of GRB prompt emission thanks to its extraordinarily high photon statistics and its single broad pulse overall shape characterized by an energy-dependent fast-rise-exponential-decay (FRED) profile. Here we demonstrate that its broad pulse is composed of many rapidly variable short pulses, rather than being the superposition of many short pulses on top of a slow component. Such a feature is consistent with the picture of many mini-jets due to local magnetic reconnection events in a large emission zone far from the GRB central engine, as envisaged in the internal-collision-induced magnetic reconnection and turbulence (ICMART) model, but raises a great challenge to the internal shock models that attribute all variability components to collisions among different shells. Since relativistic mini-jets demand strong magnetization in the outflow, this work provides strong evidence for a Poynting-flux-dominated jet composition of this bright GRB., Comment: 7 pages and 2 figures in the main text. 27 pages and 9 figures in total
Published: 2023

11. Observation of gamma rays up to 320 TeV from the middle-aged TeV pulsar wind nebula HESS J1849$-$000

Author: Amenomori, M., Asano, S., Bao, Y. W., Bi, X. J., Chen, D., Chen, T. L., Chen, W. Y., Chen, Xu, Chen, Y., Cirennima, Cui, S. W., Danzengluobu, Ding, L. K., Fang, J. H., Fang, K., Feng, C. F., Feng, Zhaoyang, Feng, Z. Y., Gao, Qi, Gomi, A., Gou, Q. B., Guo, Y. Q., Guo, Y. Y., Hayashi, Y., He, H. H., He, Z. T., Hibino, K., Hotta, N., Hu, Haibing, Hu, H. B., Hu, K. Y., Huang, J., Jia, H. Y., Jiang, L., Jiang, P., Jin, H. B., Kasahara, K., Katayose, Y., Kato, C., Kato, S., Kawahara, I., Kawashima, T., Kawata, K., Kozai, M., Kurashige, D., Labaciren, Le, G. M., Li, A. F., Li, H. J., Li, W. J., Li, Y., Lin, Y. H., Liu, B., Liu, C., Liu, J. S., Liu, L. Y., Liu, M. Y., Liu, W., Lu, H., Meng, X. R., Meng, Y., Munakata, K., Nagaya, K., Nakamura, Y., Nakazawa, Y., Nanjo, H., Ning, C. C., Nishizawa, M., Noguchi, R., Ohnishi, M., Okukawa, S., Ozawa, S., Qian, X., Qian, X. L., Qu, X. B., Saito, T., Sakakibara, Y., Sakata, M., Sako, T., Sako, T. K., Sasaki, T., Shao, J., Shibata, M., Shiomi, A., Sugimoto, H., Takano, W., Takita, M., Tan, Y. H., Tateyama, N., Torii, S., Tsuchiya, H., Udo, S., Wang, H., Wang, S. F., Wang, Y. P., Wangdui, Wu, H. R., Wu, Q., Xu, J. L., Xue, L., Yang, Z., Yao, Y. Q., Yin, J., Yokoe, Y., Yu, Y. L., Yuan, A. F., Zhai, L. M., Zhang, H. M., Zhang, J. L., Zhang, X., Zhang, X. Y., Zhang, Y., Zhang, Yi, Zhang, Ying, Zhao, S. P., Zhaxisangzhu, Zhou, X. X., and Zou, Y. H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Gamma rays from HESS J1849$-$000, a middle-aged TeV pulsar wind nebula (PWN), are observed by the Tibet air shower array and the muon detector array. The detection significance of gamma rays reaches $4.0\, \sigma$ and $4.4\, \sigma$ levels above 25 TeV and 100 TeV, respectively, in units of Gaussian standard deviation $\sigma$. The energy spectrum measured between $40\, {\rm TeV} < E < 320\, {\rm TeV}$ for the first time is described with a simple power-law function of ${\rm d}N/{\rm d}E = (2.86 \pm 1.44) \times 10^{-16}(E/40\, {\rm TeV})^{-2.24 \pm 0.41}\, {\rm TeV}^{-1}\, {\rm cm}^{-2}\, {\rm s}^{-1}$. The gamma-ray energy spectrum from the sub-TeV ($E < 1\, {\rm TeV}$) to sub-PeV ($100\, {\rm TeV} < E < 1\, {\rm PeV}$) ranges including the results of previous studies can be modeled with the leptonic scenario, inverse Compton scattering by high-energy electrons accelerated by the PWN of PSR J1849$-$0001. On the other hand, the gamma-ray energy spectrum can also be modeled with the hadronic scenario in which gamma rays are generated from the decay of neutral pions produced by collisions between accelerated cosmic-ray protons and the ambient molecular cloud found in the gamma-ray emitting region. The cutoff energy of cosmic-ray protons $E_{\rm p\, cut}$, cut is estimated at ${\rm log}_{10}(E_{\rm p,\, cut}/{\rm TeV}) = 3.73^{+2.98}_{-0.66}$, suggesting that protons are accelerated up to the PeV energy range. Our study thus proposes that HESS J1849$-$000 should be further investigated as a new candidate for a Galactic PeV cosmic-ray accelerator, PeVatron., Comment: 10 pages, 2 figures, Accepted for publication from the Astrophysical Journal
Published: 2023
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12. Measurement of the Gamma-Ray Energy Spectrum beyond 100 TeV from the HESS J1843$-$033 Region

Author: Amenomori, M., Asano, S., Bao, Y. W., Bi, X. J., Chen, D., Chen, T. L., Chen, W. Y., Chen, Xu, Chen, Y., Cirennima, Cui, S. W., Danzengluobu, Ding, L. K., Fang, J. H., Fang, K., Feng, C. F., Feng, Zhaoyang, Feng, Z. Y., Gao, Qi, Gomi, A., Gou, Q. B., Guo, Y. Q., Guo, Y. Y., He, H. H., He, Z. T., Hibino, K., Hotta, N., Hu, Haibing, Hu, H. B., Hu, K. Y., Huang, J., Jia, H. Y., Jiang, L., Jiang, P., Jin, H. B., Kasahara, K., Katayose, Y., Kato, C., Kato, S., Kawashima, T., Kawata, K., Kozai, M., Kurashige, D., Labaciren, Le, G. M., Li, A. F., Li, H. J., Li, W. J., Li, Y., Lin, Y. H., Liu, B., Liu, C., Liu, J. S., Liu, L. Y., Liu, M. Y., Liu, W., Liu, X. L., Lou, Y. -Q., Lu, H., Meng, X. R., Meng, Y., Munakata, K., Nagaya, K., Nakamura, Y., Nakazawa, Y., Nanjo, H., Ning, C. C., Nishizawa, M., Ohnishi, M., Okukawa, S., Ozawa, S., Qian, L., Qian, X., Qian, X. L., Qu, X. B., Saito, T., Sakakibara, Y., Sakata, M., Sako, T., Sako, T. K., Shao, J., Shibata, M., Shiomi, A., Sugimoto, H., Takano, W., Takita, M., Tan, Y. H., Tateyama, N., Torii, S., Tsuchiya, H., Udo, S., Wang, H., Wang, Y. P., Wangdui, Wu, H. R., Wu, Q., Xu, J. L., Xue, L., Yang, Z., Yao, Y. Q., Yin, J., Yokoe, Y., Yu, N. P., Yuan, A. F., Zhai, L. M., Zhang, C. P., Zhang, H. M., Zhang, J. L., Zhang, X., Zhang, X. Y., Zhang, Y., Zhang, Yi, Zhang, Ying, Zhao, S. P., Zhaxisangzhu, and Zhou, X. X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: HESS J1843$-$033 is a very-high-energy gamma-ray source whose origin remains unidentified. This work presents, for the first time, the energy spectrum of gamma rays beyond $100\, {\rm TeV}$ from the HESS J1843$-$033 region using the data recorded by the Tibet air shower array and its underground muon detector array. A gamma-ray source with an extension of $0.34^{\circ} \pm 0.12^{\circ}$ is successfully detected above $25\, {\rm TeV}$ at $(\alpha,\, \delta) = (281.09^{\circ}\pm 0.10^{\circ},\, -3.76^{\circ}\pm 0.09^{\circ})$ near HESS J1843$-$033 with a statistical significance of $6.2\, \sigma$, and the source is named TASG J1844$-$038. The position of TASG J1844$-$038 is consistent with those of HESS J1843$-$033, eHWC J1842$-$035, and LHAASO J1843$-$0338. The measured gamma-ray energy spectrum in $25\, {\rm TeV} < E < 130\, {\rm TeV}$ is described with ${\rm d}N/{\rm d}E = (9.70\pm 1.89)\times 10^{-16} (E/40\, {\rm TeV})^{-3.26\pm 0.30}\, {\rm TeV}^{-1} {\rm cm}^{-2} {\rm s}^{-1}$, and the spectral fit to the combined spectra of HESS J1843$-$033, LHAASO J1843$-$0338, and TASG J1844$-$038 implies the existence of a cutoff at $49.5\pm 9.0\, {\rm TeV}$. Associations of TASG J1844-038 with SNR G28.6$-$0.1 and PSR J1844-0346 are also discussed in detail for the first time., Comment: 11 pages, 4 figures, 1 table
Published: 2023
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13. The First GECAM Observation Results on Terrestrial Gamma-ray Flashes and Terrestrial Electron Beams

Author: Zhao, Y., Liu, J. C., Xiong, S. L., Xue, W. C., Yi, Q. B., Lu, G. P., Xu, W., Lyu, F. C., Sun, J. C., Peng, W. X., Zheng, C., Zhang, Y. Q., Cai, C., Xiao, S., Xie, S. L., Wang, C. W., Tan, W. J., An, Z. H., Chen, G., Du, Y. Q., Huang, Y., Gao, M., Gong, K., Guo, D. Y., He, J. J., Li, B., Li, G., Li, X. Q., Li, X. B., Liao, J. Y., Liang, J., Liang, X. H., Liu, Y. Q., Ma, X., Qiao, R., Song, L. M., Song, X. Y., Sun, X. L., Wang, J., Wang, J. Z., Wang, P., Wen, X. Y., Wu, H., Xu, Y. B., Yang, S., Zhang, B. X., Zhang, D. L., Zhang, F., Zhang, P., Zhang, H. M., Zhang, Z., Zhao, X. Y., Zheng, S. J., Zhang, K. K., Han, X. B., Wu, H. Y., Hu, T., Geng, H., Zhang, H. B., Lu, F. J., Zhang, S. N., and Yu, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Gravitational-wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) is a space-borne instrument dedicated to monitoring high-energy transients, including Terrestrial Gamma-ray Flashes (TGFs) and Terrestrial Electron Beams (TEBs). We implemented a TGF/TEB search algorithm for GECAM, with which 147 bright TGFs, 2 typical TEBs and 2 special TEB-like events are identified during an effective observation time of $\sim$9 months. We show that, with gamma-ray and charged particle detectors, GECAM can effectively identify and distinguish TGFs and TEBs, and measure their temporal and spectral properties in detail. A very high TGF-lightning association rate of $\sim$80\% is obtained between GECAM and GLD360 in east Asia region., Comment: The paper was accepted by Geophysical Research Letters on June 16th, 2023
Published: 2023
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14. Development of a diagnostic model for pre-washout screening of primary aldosteronism

Author: Wang, Q., Dong, H., LI, H.-W., Zheng, Z.-H., Liu, Y.-Z., Hua, Y.-H., Xiong, Y.-J., Zhang, H.-M., Song, L., Zou, Y.-B., and Jiang, X.-J.
Published: 2024
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15. The First LHAASO Catalog of Gamma-Ray Sources

Author: Cao, Zhen, Aharonian, F., An, Q., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo., X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology
Abstract: 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 (LHAASO). The catalog was compiled using 508 days of data collected by the Water Cherenkov Detector Array (WCDA) from March 2021 to September 2022 and 933 days of data recorded by the Kilometer Squared Array (KM2A) from January 2020 to September 2022. This catalog represents the main result from the most sensitive large coverage gamma-ray survey of the sky above 1 TeV, covering declination from $-$20$^{\circ}$ to 80$^{\circ}$. In total, the catalog contains 90 sources with an extended size smaller than $2^\circ$ and a significance of detection at $> 5\sigma$. 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 $> 4\sigma$ significance level. We provide the position, extension, and spectral characteristics of all the sources in this catalog., Comment: 40 pages, 13 figures, 4 tables
Published: 2023
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16. Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A

Author: Cao, Zhen, Aharonian, F., An, Q., Axikegu, Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Q., Cao, W. Y., Cao, Zhe, Chang, J., Chang, J. F., Chen, A. M., Chen, E. S., Chen, Liang, Chen, Lin, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, M. Y., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Dong, X. Q., Duan, K. K., Fan, J. H., Fan, Y. Z., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gabici, S., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Giacinti, G., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. Y., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, B. W., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S. C., Huang, D. H., Huang, T. Q., Huang, W. J., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, X. W., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Kurinov, K., Li, B. B., Li, Cheng, Li, Cong, Li, D., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Min, Z., Mitthumsiri, W., Mu, H. J., Nan, Y. C., Neronov, A., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Saiz, A., Semikoz, D., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shu, F. W., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Q. W., Tang, Z. B., Tian, W. W., Wang, C., Wang, C. B., Wang, G. W., Wang, H. G., Wang, H. H., Wang, J. C., Wang, K., Wang, L. P., Wang, L. Y., Wang, P. H., Wang, R., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. F., Xu, R. X., Xu, W. L., Xue, L., Yan, D. H., Yan, J. Z., Yan, T., Yang, C. W., Yang, F., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zha, M., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zhou, B., Zhou, H., Zhou, J. N., Zhou, M., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The diffuse Galactic $\gamma$-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 work we report the measurements of diffuse $\gamma$-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 ($15^{\circ}10$~TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of $-2.99\pm0.04$, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of $\sim3$ than the prediction. A similar spectrum with an index of $-2.99\pm0.07$ is found in the outer Galaxy region, and the absolute flux for $10\lesssim E\lesssim60$ TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations., Comment: 12 pages, 8 figures, 5 tables; accepted for publication in Physical Review Letters; source mask file provided as ancillary file
Published: 2023
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17. A Review on Vector Form Intrinsic Finite Element Method and Its Application

Author: Duan, Y. F., Fang, Y., Wang, S. M., Wu, S. K., Zhang, H. M., Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, and Li, Shaofan, editor
Published: 2024
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18. Flux Variations of Cosmic Ray Air Showers Detected by LHAASO-KM2A During a Thunderstorm on 10 June 2021

Author: LHAASO Collaboration, Aharonian, F., An, Q., Axikegu, Bai, L. X., Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Zhe, Cao, Zhen, Chang, J., Chang, J. F., Chen, E. S., Chen, Liang, Chen, Long, Chen, M. J., Chen, M. L., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, X. J., Chen, Y., Cheng, H. L., Cheng, N., Cheng, Y. D., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Duan, K. K., Fan, J. H., Fan, Y. Z., Fan, Z. X., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Gong, G. H., Gou, Q. B., Gu, M. H., Gu, F. L., Guo, J. G., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, S. L., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S., Hu, S. C., Hu, X. J., Huang, D. H., Huang, W. H., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Li, B. B., Li, Cheng, Li, Cong, Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. S., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Long, W. J., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Masood, A., Min, Z., Mitthumsiri, W., Nan, Y. C., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shi, J. Y., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Z. B., Tian, W. W., Wang, B. D., Wang, C., Wang, H., Wang, H. G., Wang, J. C., Wang, J. S., Wang, L. P., Wang, L. Y., Wang, R., Wang, R. N., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Y. P., Wang, Z. H. Wang. Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., W, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. X., Xue, L., Yan, D. H., Yan, J. Z., Yang, C. W., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zeng, Z. K., Zha, M., Zhai, X. X., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, Lu, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Y. L., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, Y., Zhou, B., Zhou, H., Zhou, J. N., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: The Large High Altitude Air Shower Observatory (LHAASO) has three sub-arrays, KM2A, WCDA and WFCTA. The flux variations of cosmic ray air showers were studied by analyzing the KM2A data during the thunderstorm on 10 June 2021. The number of shower events that meet the trigger conditions increases significantly in atmospheric electric fields, with maximum fractional increase of 20%. The variations of trigger rates (increases or decreases) are found to be strongly dependent on the primary zenith angle. The flux of secondary particles increases significantly, following a similar trend with that of the shower events. To better understand the observed behavior, Monte Carlo simulations are performed with CORSIKA and G4KM2A (a code based on GEANT4). We find that the experimental data (in saturated negative fields) are in good agreement with simulations, assuming the presence of a uniform upward electric field of 700 V/cm with a thickness of 1500 m in the atmosphere above the observation level. Due to the acceleration/deceleration and deflection by the atmospheric electric field, the number of secondary particles with energy above the detector threshold is modified, resulting in the changes in shower detection rate., Comment: 18 pages, 11 figures
Published: 2022
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19. Oscillation growth in mixed traffic flow of human driven vehicles and automated vehicles: Experimental study and simulation

Author: Zheng, Shiteng, Jiang, Rui, Zhang, H. M., Tian, Junfang, Yan, Ruidong, Jia, Bin, and Gao, Ziyou
Subjects: Physics - Physics and Society
Abstract: This paper reports an experimental study on oscillation growth in mixed traffic flow of automated vehicles (AVs) and human driven vehicles (HVs). The leading vehicle moves with constant speed in the experiment. The following vehicles consist of six developable AVs and different number of HVs. Thus, the market penetration rate (MPR) of AVs decreases with the increase of platoon size. The AVs are homogeneously distributed in the platoon. The constant time gap car-following policy is adopted for the AVs and the gap is set to 1.5 s. The experiment shows that in the 7-vehicle-platoon, the oscillations grow only slightly. In the 10-vehicle-platoon, the AVs could still significantly suppress the growth of oscillations. With the further decrease of MPR of AVs in the 13- and 20-vehicle-platoon, the AVs become having no significant impact on oscillation growth. On the other hand, with the decrease of MPR of AVs, average density of the vehicles and flow rate of the platoon increase, which demonstrates a trade-off between traffic stability and throughput under the given setup of AVs. The simulation study is also carried out, which exhibits good agreement with the experiment. Finally, sensitivity analysis of the parameters in the AV upper-level control algorithm has been performed, which is expected to guide future experiment design.
Published: 2022

20. Peculiar disk behaviors of the black hole candidate MAXI J1348-630 in the hard state observed by Insight-HXMT and Swift

Author: Zhang, W., Tao, L., Soria, R., Qu, J. L., Zhang, S. N., Weng, S. S., zhang, L., Wang, Y. N., Huang, Y., Ma, R. C., Zhang, S., Ge, M. Y., Song, L. M., Ma, X., Bu, Q. C., Cai, C., Cao, X. L., Chang, Z., Chen, L., Chen, T. X., Chen, Y. B., Chen, Y., Chen, Y. P., Cui, W. W., Du, Y. Y., Gao, G. H., Gao, H., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, T. P., Li, W., Li, X., Li, X. B., Li, X. F., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, C. Z., Liu, H. X., Liu, H. W., Liu, X. J., Lu, F. J., Lu, X. F., Luo, Q., Luo, T., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Ren, X. Q., Sai, N., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, L. J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, R. J., Yang, S., Yang, Y. J., Yang, Y. R., Yi, Q. B., Yin, Q. Q., Yuan, Y., Zhang, F., Zhang, H. M., Zhang, P., Zhang, W. C., Zhang, Y. F., Zhang, Y. H., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present a spectral study of the black hole candidate MAXI J1348-630 during its 2019 outburst, based on monitoring observations with Insight-HXMT and Swift. Throughout the outburst, the spectra are well fitted with power-law plus disk-blackbody components. In the soft-intermediate and soft states, we observed the canonical relation L ~ T_in^4 between disk luminosity L and peak colour temperature T_in, with a constant inner radius R_in (traditionally identified with the innermost stable circular orbit). At other stages of the outburst cycle, the behaviour is more unusual, inconsistent with the canonical outburst evolution of black hole transients. In particular, during the hard rise, the apparent inner radius is smaller than in the soft state (and increasing), and the peak colour temperature is higher (and decreasing). This anomalous behaviour is found even when we model the spectra with self-consistent Comptonization models, which take into account the up-scattering of photons from the disk component into the power-law component. To explain both those anomalous trends at the same time, we suggest that the hardening factor for the inner disk emission was larger than the canonical value of ~1.7 at the beginning of the outburst. A more physical trend of radii and temperature evolution requires a hardening factor evolving from ~3.5 at the beginning of the hard state to ~1.7 in the hard intermediate state. This could be evidence that the inner disk was in the process of condensing from the hot, optically thin medium and had not yet reached a sufficiently high optical depth for its emission spectrum to be described by the standard optically-thick disk solution., Comment: 20 pages, 10 figures, 4 tables, accepted by ApJ
Published: 2022
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21. GECAM detection of a bright type-I X-ray burst from 4U 0614+09: confirmation its spin frequency at 413 Hz

Author: Chen, Y. P., Li, J., Xiong, S. L., Ji, L., Zhang, S., Peng, W. X., Qiao, R., Li, X. Q., Wen, X. Y., Song, L. M., Zheng, S. J., Song, X. Y., Zhao, X. Y., Huang, Y., Lu, F. J., Zhang, S. N., Xiao, S., Cai, C., Zhang, B. X., An, Z. H., Chen, C., Chen, G., Chen, W., Dai, G. Q., Du, Y. Q., Gao, M., Gong, K., Guo, D. Y., Guo, Z. W., He, J. J., Li, B., Li, C., Li, C. Y., Li, G., Li, J. H., Li, L., Li, Q. X., Li, X. B., Li, Y. G., Liang, J., Liang, X. H., Liao, J. Y., Liu, J. C., Liu, X. J., Liu, Y. Q., Luo, Q., Ma, X., Meng, B., Ou, G., Shi, D. L., Shi, F., Shi, J. Y., Sun, G. X., Sun, X. L., Tuo, Y. L., Wang, C. W., Wang, H., Wang, H. Y., Wang, J., Wang, J. Z., Wang, P., Wang, Y. S., Wang, Y. X., Wen, X., Wu, H., Xie, S. L., Xu, Y. B., Xu, Y. P., Xue, W. C., Yang, S., Yao, M., Ye, J. Y., Yi, Q. B., Zhang, C. M., Zhang, C. Y., Zhang, D. L., Zhang, Fan, Zhang, Fei, Zhang, H. M., Zhang, K., Zhang, P., Zhang, X. L., Zhang, Y. Q., Zhang, Z., Zhao, G. Y., Zhao, S. Y., Zhao, Y., Zheng, C., Zhou, X., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: One month after launching Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM), a bright thermonuclear X-ray burst from 4U~0614+09, was observed on January 24, 2021. We report the time-resolved spectroscopy of the burst and a burst oscillation detection at 413 Hz with a fractional amplitude 3.4\% (rms). This coincides with the burst oscillation previously discovered with \textit{Swift}/BAT \citep{Strohmayer2008}, and therefore confirms the spin frequency of this source. This burst is the brightest one in the normal bursts (except the superburst) ever detected from 4U~0614+09, which leads to an upper limit of distance estimation as 3.1 kpc. The folded light curve during the burst oscillation shows a multi-peak structure, which is the first case observed during a single burst oscillation in nonpulsating sources. The multi-peak profile could be due to additional harmonics of the burst oscillation, which is corresponding to several brighter/fainter spots at the stellar surface.
Published: 2021
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22. Peta-electron volt gamma-ray emission from the Crab Nebula

Author: The LHAASO Collaboration, Cao, Zhen, Aharonian, F., An, Q., Axikegu, Bai, L. X., Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, H., Cai, J. T., Cao, Zhe, Chang, J., Chang, J. F., Chen, B. M., Chen, E. S., Chen, J., Chen, Liang, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, X. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, S. W., Cui, X. H., Cui, Y. D., Piazzoli, B. D'Ettorre, Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Dong, X. J., Duan, K. K., Fan, J. H., Fan, Y. Z., Fan, Z. X., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, Y. L., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Ge, M. M., Geng, L. S., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, J. G., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. C., He, S. L., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, C., Hou, X., Hu, H. B., Hu, S., Hu, S. C., Hu, X. J., Huang, D. H., Huang, Q. L., Huang, W. H., Huang, X. T., Huang, X. Y., Huang, Z. C., Ji, F., Ji, X. L., Jia, H. Y., Jiang, K., Jiang, Z. J., Jin, C., Ke, T., Kuleshov, D., Levochkin, K., Li, B. B., Li, Cheng, Li, Cong, Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, Jie, Li, Jian, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Y., Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. S., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Liu, Z. X., Long, W. J., Lu, R., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Masood, A., Min, Z., Mitthumsiri, W., Montaruli, T., Nan, Y. C., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Rulev, V., Sáiz, A., Shao, L., Shchegolev, O., Sheng, X. D., Shi, J. Y., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Z. B., Tian, W. W., Wang, B. D., Wang, C., Wang, H., Wang, H. G., Wang, J. C., Wang, J. S., Wang, L. P., Wang, L. Y., Wang, R. N., Wang, Wei, Wang, X. G., Wang, X. J., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Y. P., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, W. X., Wu, X. F., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xiao, H. B., Xin, G. G., Xin, Y. L., Xing, Y., Xu, D. L., Xu, R. X., Xue, L., Yan, D. H., Yan, J. Z., Yang, C. W., Yang, F. F., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Zeng, H. D., Zeng, T. X., Zeng, W., Zeng, Z. K., Zha, M., Zhai, X. X., Zhang, B. B., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, J. W., Zhang, L. X., Zhang, Li, Zhang, Lu, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Y. L., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, Y., Zhou, B., Zhou, H., Zhou, J. N., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The Crab pulsar and the surrounding nebula powered by the pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind is a bright source of gamma-rays carrying crucial information about this complex conglomerate. We report the detection of $\gamma$-rays with a spectrum showing gradual steepening over three energy decades, from $5\times 10^{-4}$ to $1.1$ petaelectronvolt (PeV). The ultra-high-energy photons exhibit the presence of a PeV electron accelerator (a pevatron) with an acceleration rate exceeding 15% of the absolute theoretical limit. Assuming that unpulsed $\gamma$-rays are produced at the termination of the pulsar's wind, we constrain the pevatron's size, between $0.025$ and $0.1$ pc, and the magnetic field $\approx 110 \mu$G. The production rate of PeV electrons, $2.5 \times 10^{36}$ erg $\rm s^{-1}$, constitutes 0.5% of the pulsar's spin-down luminosity, although we do not exclude a non-negligible contribution of PeV protons to the production of the highest energy $\gamma$-rays., Comment: 43 pages, 13 figures, 2 tables; Published in Science
Published: 2021
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23. Search for Gamma-Ray Bursts and Gravitational Wave Electromagnetic Counterparts with High Energy X-ray Telescope of \textit{Insight}-HXMT

Author: Cai, C., Xiong, S. L., Li, C. K., Liu, C. Z., Zhang, S. N., Li, X. B., Song, L. M., Li, B., Xiao, S., Yi, Q. B., Zhu, Y., Zheng, Y. G., Chen, W., Luo, Q., Huang, Y., Song, X. Y., Zhao, H. S., Zhao, Y., Zhang, Z., Bu, Q. C., Cao, X. L., Chang, Z., Chen, L., Chen, T. X., Chen, Y. B., Chen, Y., Chen, Y. P., Cui, W. W., Du, Y. Y., Gao, G. H., Gao, H., Ge, M. Y., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Kong, L. D., Li, G., Li, T. P., Li, W., Li, X., Li, X. F., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, H. W., Liu, H. X., Liu, X. J., Lu, F. J., Lu, X. F., Luo, T., Ma, R. C., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Qu, J. L., Ren, X. Q., Sai, N., Sun, L., Tan, Y., Tao, L., Tuo, Y. L., Wang, C., Wang, L. J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xu, Y. P., Yang, R. J., Yang, S., Yang, Y. J., Yang, Y. R., Yang, X. J., Yin, Q. Q., You, Y., Zhang, F., Zhang, H. M., Zhang, J., Zhang, P., Zhang, S., Zhang, W. C., Zhang, W., Zhang, Y. F., Zhang, Y. H., Zhao, X. F., Zheng, S. J., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The High Energy X-ray telescope (HE) on-board the Hard X-ray Modulation Telescope (\textit{Insight}-HXMT) can serve as a wide Field of View (FOV) gamma-ray monitor with high time resolution ($\mu$s) and large effective area (up to thousands cm$^2$). We developed a pipeline to search for Gamma-Ray Bursts (GRBs), using the traditional signal-to-noise ratio (SNR) method for blind search and the coherent search method for targeted search. By taking into account the location and spectrum of the burst and the detector response, the targeted coherent search is more powerful to unveil weak and sub-threshold bursts, especially those in temporal coincidence with Gravitational Wave (GW) events. Based on the original method in literature, we further improved the coherent search to filter out false triggers caused by spikes in light curves, which are commonly seen in gamma-ray instruments (e.g. \textit{Fermi}/GBM, \textit{POLAR}). We show that our improved targeted coherent search method could eliminate almost all false triggers caused by spikes. Based on the first two years of \textit{Insight}-HXMT/HE data, our targeted search recovered 40 GRBs, which were detected by either \textit{Swift}/BAT or \textit{Fermi}/GBM but too weak to be found in our blind search. With this coherent search pipeline, the GRB detection sensitivity of \textit{Insight}-HXMT/HE is increased to about 1.5E-08 erg/cm$^2$ (200 keV$-$3 MeV). We also used this targeted coherent method to search \textit{Insight}-HXMT/HE data for electromagnetic (EM) counterparts of LIGO-Virgo GW events (including O2 and O3a runs). However, we did not find any significant burst associated with GW events., Comment: 12 pages, 14 figures, 5 tables; accepted for publication in MNRAS
Published: 2021
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24. Potential PeVatron supernova remnant G106.3+2.7 seen in the highest-energy gamma rays

Author: Amenomori, M., Bao, Y. W., Bi, X. J., Chen, D., Chen, T. L., Chen, W. Y., Chen, Xu, Chen, Y., Cirennima, Cui, S. W., Danzengluobu, Ding, L. K., Fang, J. H., Fang, K., Feng, C. F., Feng, Zhaoyang, Feng, Z. Y., Gao, Qi, Gou, Q. B., Guo, Y. Q., Guo, Y. Y., He, H. H., He, Z. T., Hibino, K., Hotta, N., Hu, Haibing, Hu, H. B., Huang, J., Jia, H. Y., Jiang, L., Jin, H. B., Kasahara, K., Katayose, Y., Kato, C., Kato, S., Kawata, K., Kihara, W., Ko, Y., Kozai, M., Labaciren, Le, G. M., Li, A. F., Li, H. J., Li, W. J., Lin, Y. H., Liu, B., Liu, C., Liu, J. S., Liu, M. Y., Liu, W., Lou, Y. -Q., Lu, H., Meng, X. R., Munakata, K., Nakada, H., Nakamura, Y., Nanjo, H., Nishizawa, M., Ohnishi, M., Ohura, T., Ozawa, S., Qian, X. L., Qu, X. B., Saito, T., Sakata, M., Sako, T. K., Shao, J., Shibata, M., Shiomi, A., Sugimoto, H., Takano, W., Takita, M., Tan, Y. H., Tateyama, N., Torii, S., Tsuchiya, H., Udo, S., Wang, H., Wu, H. R., Xue, L., Yamamoto, Y., Yang, Z., Yokoe, Y., Yuan, A. F., Zhai, L. M., Zhang, H. M., Zhang, J. L., Zhang, X., Zhang, X. Y., Zhang, Y., Zhang, Yi, Zhang, Ying, Zhao, S. P., Zhaxisangzhu, and Zhou, X. X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Cosmic rays (protons and other atomic nuclei) are believed to gain energies of petaelectronvolts (PeV) and beyond at astrophysical particle accelerators called 'PeVatrons' inside our Galaxy. Although a characteristic feature of a PeVatron is expected to be a hard gamma-ray energy spectrum that extends beyond 100 teraelectronvolts (TeV) without a cutoff, none of the currently known sources exhibits such a spectrum due to the low maximum energy of accelerated cosmic rays or insufficient detector sensitivity around 100 TeV. Here we report the observation of gamma-ray emission from the supernova remnant G106.3+2.7 above 10 TeV. This work provides flux data points up to and above 100 TeV and indicates that the very-high-energy gamma-ray emission above 10 TeV is well correlated with a molecular cloud rather than the pulsar PSR J2229+6114. Regarding the gamma-ray emission mechanism of G106.3+2.7, this morphological feature appears to favor a hadronic origin via the {\pi}0 decay caused by accelerated relativistic protons over a leptonic one via the inverse-Compton scattering by relativistic electrons. Furthermore, we point out that an X-ray flux upper limit on the synchrotron spectrum would provide important information to firmly establish the hadronic scenario as the mechanism of particle acceleration at the source., Comment: Published in Nature Astronomy
Published: 2021
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25. Gamma-ray Observation of the Cygnus Region in the 100 TeV Energy Region

Author: Amenomori, M., Bao, Y. W., Bi, X. J., Chen, D., Chen, T. L., Chen, W. Y., Chen, Xu, Chen, Y., Cirennima, Cui, S. W., Danzengluobu, Ding, L. K., Fang, J. H., Fang, K., Feng, C. F., Feng, Zhaoyang, Feng, Z. Y., Gao, Qi, Gomi, A., Gou, Q. B., Guo, Y. Q., Guo, Y. Y., He, H. H., He, Z. T., Hibino, K., Hotta, N., Hu, Haibing, Hu, H. B., Huang, J., Jia, H. Y., Jiang, L., Jiang, P., Jin, H. B., Kasahara, K., Katayose, Y., Kato, C., Kato, S., Kawata, K., Kozai, M., Kurashige, D., Labaciren, Le, G. M., Li, A. F., Li, H. J., Li, W. J., Li, Y., Lin, Y. H., Liu, B., Liu, C., Liu, J. S., Liu, L. Y., Liu, M. Y., Liu, W., Liu, X. L., Lou, Y. -Q., Lu, H., Meng, X. R., Munakata, K., Nakada, H., Nakamura, Y., Nakazawa, Y., Nanjo, H., Ning, C. C., Nishizawa, M., Ohnishi, M., Ohura, T., Okukawa, S., Ozawa, S., Qian, L., Qian, X., Qian, X. L., Qu, X. B., Saito, T., Sakata, M., Sako, T., Sako, T. K., Shao, J., Shibata, M., Shiomi, A., Sugimoto, H., Takano, W., Takita, M., Tan, Y. H., Tateyama, N., Torii, S., Tsuchiya, H., Udo, S., Wang, H., Wang, Y. P., Wangdui, Wu, H. R., Wu, Q., Xu, J. L., Xue, L., Yamamoto, Y., Yang, Z., Yao, Y. Q., Yin, J., Yokoe, Y., Yu, N. P., Yuan, A. F., Zhai, L. M., Zhang, C. P., Zhang, H. M., Zhang, J. L., Zhang, X., Zhang, X. Y., Zhang, Y., Zhang, Yi, Zhang, Ying, Zhao, S. P., Zhaxisangzhu, and Zhou, X. X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report observations of gamma-ray emissions with energies in the 100 TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1 with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources., Comment: Accepted for publication in the Physical Review Letters
Published: 2021
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26. Magnetic structure and multiferroicity of Sc-substituted hexagonal YbFeO$_3$

Author: Tang, Y. S., Wang, S. M., Lin, L., Garlea, V. Ovidiu, Zou, Tao, Zheng, S. H., Zhang, H. -M., Zhou, J. T., Luo, Z. L., Yan, Z. B., Dong, S., Charlton, T., and Liu, J. -M.
Subjects: Condensed Matter - Materials Science
Abstract: Hexagonal rare-earth ferrite RFeO$_3$ family represents a unique class of multiferroics exhibiting weak ferromagnetism, and a strong coupling between magnetism and structural trimerization is predicted. However, the hexagonal structure for RFeO$_3$ remains metastable in conventional condition. We have succeeded in stabilizing the hexagonal structure of polycrystalline YbFeO$_3$ by partial Sc substitution of Yb. Using bulk magnetometry and neutron diffraction, we find that Yb$_{0.42}$Sc$_{0.58}$FeO$_3$ orders into a canted antiferromagnetic state with the Neel temperature $T_N$ ~ 165 K, below which the $Fe^{3+}$ moments form the triangular configuration in the $ab$-plane and their in-plane projections are parallel to the [100] axis, consistent with magnetic space group $P$6$_{3}$$c'm'$. It is determined that the spin-canting is aligned along the $c$-axis, giving rise to the weak ferromagnetism. Furthermore, the $Fe^{3+}$ moments reorient toward a new direction below reorientation temperature $T_R$ ~ 40 K, satisfying magnetic subgroup $P$6$_{3}$, while the $Yb^{3+}$ moments order independently and ferrimagnetically along the $c$-axis at the characteristic temperature $T_{Yb}$ ~ 15 K. Interestingly, reproducible modulation of electric polarization induced by magnetic field at low temperature is achieved, suggesting that the delicate structural distortion associated with two-up/one-down buckling of the Yb/Sc-planes and tilting of the FeO$_5$ bipyramids may mediate the coupling between ferroelectric and magnetic orders under magnetic field. The present work represents a substantial progress to search for high-temperature multiferroics in hexagonal ferrites and related materials.
Published: 2021
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27. Calibration of the Air Shower Energy Scale of the Water and Air Cherenkov Techniques in the LHAASO experiment

Author: Aharonian, F., An, Q., Axikegu, Bai, L. X., Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, H., Cai, J. T., Cao, Z. Cao Z., Chang, J., Chang, J. F., Chang, X. C., Chen, B. M., Chen, J., Chen, L., Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, X. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Piazzoli, B. DEttorre, Dong, X. J., Fan, J. H., Fan, Y. Z., Fan, Z. X., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, Y. L., Gao, B., Gao, C. D., Gao, Q., Gao, W., Ge, M. M., Geng, L. S., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, J. G., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. C., He, S. L., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, C., Hou, X., Hu, H. B., Hu, S., Hu, S. C., Hu, X. J., Huang, D. H., Huang, Q. L., Huang, W. H., Huang, X. T., Huang, Z. C., Ji, F., Ji, X. L., Jia, H. Y., Jiang, K., Jiang, Z. J., Jin, C., Kuleshov, D., Levochkin, K., Li, B. B., Li, C., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, K., Li, W. L., Li, X., Li, X. R., Li, Y., Li, Y. Z., Li, Z., Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. S., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y. N., Liu, Z. X., Long, W. J., Lu, R., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Masood, A., Mitthumsiri, W., Montaruli, T., Nan, Y. C., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Ruffolo, D., Rulev, V., Saiz, A., Shao, L., Shchegolev, O., Sheng, X. D., Shi, J. R., Song, H. C., Stenkin, Yu. V., Stepanov, V., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Z. B., Tian, W. W., Wang, B. D., Wang, C., Wang, H., Wang, H. G., Wang, J. C., Wang, J. S., Wang, L. P., Wang, L. Y., Wang, R. N., Wang, W., Wang, X. G., Wang, X. J., Wang, X. Y., Wang, Y. D., Wang, Y. J., Wang, Y. P., Wang, Z., Wang, Z. H., Wang, Z. X., Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X., Wu, X. F., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, G., Xiao, H. B., Xin, G. G., Xin, Y. L., Xing, Y., Xu, D. L., Xu, R. X., Xue, L., Yan, D. H., Yang, C. W., Yang, F. F., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Zeng, H. D., Zeng, T. X., Zeng, W., Zeng, Z. K., Zha, M., Zhai, X. X., Zhang, B. B., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, J. W., Zhang, L., Zhang, L. X., Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y., Zhang, Y. F., Zhang, Y. L., Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, Y., Zhou, B., Zhou, H., Zhou, J. N., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: The Wide Field-of-View Cherenkov Telescope Array (WFCTA) and the Water Cherenkov Detector Arrays (WCDA) of LHAASO are designed to work in combination for measuring the energy spectra of various cosmic ray species over a very wide energy range from a few TeV to 10 PeV. The energy calibration of WCDA can be achieved with a proven technique of measuring the westward shift of the Moon shadow of galactic cosmic rays due to the geomagnetic field. This deflection angle $\Delta$ is inversely proportional to the energy of the cosmic rays. The precise measurements of the shifts by WCDA allows us to calibrate its energy scale for energies as high as 35 TeV. The energy scale measured by WCDA can be used to cross calibrate the energy reconstructed by WFCTA, which spans the whole energy range up to 10 PeV. In this work, we will demonstrate the feasibility of the method using the data collected from April 2019 to January 2020 by the WFCTA array and WCDA-1 detector, the first of the three water Cherenkov ponds, already commissioned at LHAASO site.
Published: 2021
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28. First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies

Author: Amenomori, M., Bao, Y. W., Bi, X. J., Chen, D., Chen, T. L., Chen, W. Y., Chen, Xu, Chen, Y., Cirennima, Cui, S. W., Danzengluobu, Ding, L. K., Fang, J. H., Fang, K., Feng, C. F., Feng, Zhaoyang, Feng, Z. Y., Gao, Qi, Gou, Q. B., Guo, Y. Q., Guo, Y. Y., He, H. H., He, Z. T., Hibino, K., Hotta, N., Hu, Haibing, Hu, H. B., Huang, J., Jia, H. Y., Jiang, L., Jin, H. B., Kasahara, K., Katayose, Y., Kato, C., Kato, S., Kawata, K., Kihara, W., Ko, Y., Kozai, M., Labaciren, Le, G. M., Li, A. F., Li, H. J., Li, W. J., Lin, Y. H., Liu, B., Liu, C., Liu, J. S., Liu, M. Y., Liu, W., Lou, Y. -Q., Lu, H., Meng, X. R., Munakata, K., Nakada, H., Nakamura, Y., Nanjo, H., Nishizawa, M., Ohnishi, M., Ohura, T., Ozawa, S., Qian, X. L., Qu, X. B., Saito, T., Sakata, M., Sako, T. K., Shao, J., Shibata, M., Shiomi, A., Sugimoto, H., Takano, W., Takita, M., Tan, Y. H., Tateyama, N., Torii, S., Tsuchiya, H., Udo, S., Wang, H., Wu, H. R., Xue, L., Yamamoto, Y., Yang, Z., Yokoe, Y., Yuan, A. F., Zhai, L. M., Zhang, H. M., Zhang, J. L., Zhang, X., Zhang, X. Y., Zhang, Y., Zhang, Yi, Zhang, Ying, Zhao, S. P., Zhaxisangzhu, and Zhou, X. X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and compatible with expectations from the hadronic emission scenario in which gamma rays originate from the decay of $\pi^0$'s produced through the interaction of protons with the interstellar medium in the Galaxy. This is strong evidence that cosmic rays are accelerated beyond PeV energies in our Galaxy and spread over the Galactic disk., Comment: Accepted for publication in the Physical Review Letters
Published: 2021
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29. Accretion Torque Reversals in GRO J1008-57 Revealed by Insight-HXMT

Author: Wang, W., Tang, Y. M., Tuo, Y. L., Epili, P. R., Zhang, S. N., Song, L. M., Lu, F. J., Qu, J. L., Zhang, S., Ge, M. Y., Huang, Y., Li, B., Bu, Q. C., Cai, C., Cao, X. L., Chang, Z., Chen, L., Chen, T. X., Chen, Y. B., Chen, Y., Chen, Y. P., Cui, W. W., Du, Y. Y., Gao, G. H., Gao, H., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Kong, L. D., Li, C. K., Li, G., Li, T. P., Li, W., Li, X., Li, X. B., Li, X. F., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, C. Z., Liu, H. X., Liu, H. W., Lu, X. F., Luo, Q., Luo, T., Ma, R. C., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Ren, X. Q., Sai, N., Song, X. Y., Sun, L., Tao, L., Wang, C., Wang, L. J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Xu, Y. P., Yang, R. J., Yang, S., Yang, J. J., Yang, Y. J., Yi, B. B., Yin, Q. Q., You, Y., Zhang, F., Zhang, H. M., Zhang, J., Zhang, P., Zhang, W., Zhang, W. C., Zhang, Y. F., Zhang, Y. H., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: GRO J1008-57, as a Be/X-ray transient pulsar, is considered to have the highest magnetic field in known neutron star X-ray binary systems. Observational data of the X-ray outbursts in GRO J1008-57 from 2017 to 2020 were collected by the Insight-HXMT satellite. In this work, the spin period of the neutron star in GRO J1008-57 was determined to be about 93.28 seconds in August 2017, 93.22 seconds in February 2018, 93.25 seconds in June 2019 and 93.14 seconds in June 2020. GRO J1008-57 evolved in the spin-up process with a mean rate of $-(2.10\pm 0.05)\times$10$^{-4}$ s/d from 2009 -- 2018, and turned into a spin down process with a rate of $(6.7\pm 0.6)\times$10$^{-5}$ s/d from Feb 2018 to June 2019. During the type II outburst of 2020, GRO J1008-57 had the spin-up torque again. During the torque reversals, the pulse profiles and continuum X-ray spectra did not change significantly, and the cyclotron resonant scattering feature around 80 keV was only detected during the outbursts in 2017 and 2020. Based on the observed mean spin-up rate, we estimated the inner accretion disk radius in GRO J1008-57 (about 1 - 2 times of the Alfv\'{e}n radius) by comparing different accretion torque models of magnetic neutron stars. During the spin-down process, the magnetic torque should dominate over the matter accreting inflow torque, and we constrained the surface dipole magnetic field $B\geq 6\times 10^{12}$ G for the neutron star in GRO J1008-57, which is consistent with the magnetic field strength obtained by cyclotron line centroid energy., Comment: 10 pages, 5 figures, and 3 tables, the Journal of High Energy Astrophysics in press
Published: 2021

30. QPOs and Orbital elements of X-ray binary 4U 0115+63 during the 2017 outburst observed by Insight-HXMT

Author: Ding, Y. Z., Wang, W., Zhang, P., Bu, Q. C., Cai, C., Cao, X. L., Zhi, C., Chen, L., Chen, T. X., Chen, Y. B., Chen, Y., Chen, Y. P., Cui, W. W., Du, Y. Y., Gao, G. H., Gao, H., Ge, M. Y., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, T. P., Li, W., Li, X., Li, X. B., Li, X. F., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, C. Z., Liu, H. X., Liu, H. W., Liu, X. J., Lu, F. J., Lu, X. F., L., Q., T., L., Ma, R. C., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Qu, J. L., Ren, X. Q., Sai, N., Song, L. M., Song, X. Y., Sun, L., Tan, Y., Tao, L., Tuo, Y. L., Wang, L. J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Xu, Y. P., Yang, R. J., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, F., Zhang, H. M., Zhang, J., Zhang, S., Zhang, S. N., Zhang, W. C., Zhang, W., Zhang, Y. F., Zhang, Y. H., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: In this paper, we presented a detailed timing analysis of a prominent outburst of 4U 0115+63 detected by \textit{Insight}-HXMT in 2017 August. The spin period of the neutron star was determined to be $3.61398\pm 0.00002$ s at MJD 57978. We measured the period variability and extract the orbital elements of the binary system. The angle of periastron evolved with a rate of $0.048\pm0.003$ $yr^{-1}$. The light curves are folded to sketch the pulse profiles in different energy ranges. A multi-peak structure in 1-10 keV is clearly illustrated. We introduced wavelet analysis into our data analysis procedures to study QPO signals and perform a detailed wavelet analysis in many different energy ranges. Through the wavelet spectra, we report the discovery of a QPO at the frequency $\sim 10$ mHz. In addition, the X-ray light curves showed multiple QPOs in the period of $\sim 16-32 $ s and $\sim 67- 200 $ s. We found that the $\sim100$ s QPO was significant in most of the observations and energies. There exist positive relations between X-ray luminosity and their Q-factors and S-factors, while the QPO periods have no correlation with X-ray luminosity. In wavelet phase maps, we found that the pulse phase of $\sim 67- 200 $ s QPO drifting frequently while the $\sim 16-32 $ s QPO scarcely drifting. The dissipation of oscillations from high energy to low energy was also observed. These features of QPOs in 4U 0115+63 provide new challenge to our understanding of their physical origins., Comment: 14 pages, 9 figures, and 6 tables. This work has been submitted to MNRAS after the referee's report
Published: 2021
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31. Construction and On-site Performance of the LHAASO WFCTA Camera

Author: Aharonian, F., An, Q., Axikegu, Bai, L. X., Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, H., Cai, J. T., Cao, Z., Chang, J., Chang, J. F., Chang, X. C., Chen, B. M., Chen, J., Chen, L., Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, X. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Piazzoli, B. D'Ettorre, Dong, X. J., Fan, J. H., Fan, Y. Z., Fan, Z. X., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, Y. L., Gao, B., Gao, C. D., Gao, Q., Gao, W., Ge, M. M., Geng, L. S., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, J. G., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. C., He, S. L., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, C., Hou, X., Hu, H. B., Hu, S., Hu, S. C., Hu, X. J., Huang, D. H., Huang, Q. L., Huang, W. H., Huang, X. T., Huang, Z. C., Ji, F., Ji, X. L., Jia, H. Y., Jiang, K., Jiang, Z. J., Jin, C., Kuleshov, D., Levochkin, K., Li, B. B., Li, C., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, K., Li, W. L., Li, X., Li, X. R., Li, Y., Li, Y. Z., Li, Z., Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. S., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y. N., Liu, Z. X., Long, W. J., Lu, R., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Masood, A., Mitthumsiri, W., Montaruli, T., Nan, Y. C., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Ruffolo, D., Rulev, V., Sáiz, A., Shao, L., Shchegolev, O., Sheng, X. D., Shi, J. R., Song, H. C., Stenkin, Yu. V., Stepanov, V., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Z. B., Tian, W. W., Wang, B. D., Wang, C., Wang, H., Wang, H. G., Wang, J. C., Wang, J. S., Wang, L. P., Wang, L. Y., Wang, R. N., Wang, W., Wang, X. G., Wang, X. J., Wang, X. Y., Wang, Y. D., Wang, Y. J., Wang, Y. P., Wang, Z., Wang, Z. H., Wang, Z. X., Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, W. X., Wu, X. F., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, G., Xiao, H. B., Xin, G. G., Xin, Y. L., Xing, Y., Xu, D. L., Xu, R. X., Xue, L., Yan, D. H., Yang, C. W., Yang, F. F., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Zeng, H. D., Zeng, T. X., Zeng, W., Zeng, Z. K., Zha, M., Zhai, X. X., Zhang, B. B., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, J. W., Zhang, L., Zhang, L. X., Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y., Zhang, Y. F., Zhang, Y. L., Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, Y., Zhou, B., Zhou, H., Zhou, J. N., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract: The focal plane camera is the core component of the Wide Field-of-view Cherenkov/fluorescence Telescope Array (WFCTA) of the Large High-Altitude Air Shower Observatory (LHAASO). Because of the capability of working under moonlight without aging, silicon photomultipliers (SiPM) have been proven to be not only an alternative but also an improvement to conventional photomultiplier tubes (PMT) in this application. Eighteen SiPM-based cameras with square light funnels have been built for WFCTA. The telescopes have collected more than 100 million cosmic ray events and preliminary results indicate that these cameras are capable of working under moonlight. The characteristics of the light funnels and SiPMs pose challenges (e.g. dynamic range, dark count rate, assembly techniques). In this paper, we present the design features, manufacturing techniques and performances of these cameras. Finally, the test facilities, the test methods and results of SiPMs in the cameras are reported here., Comment: 45 pages, 21 figures, article
Published: 2020
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32. Insight-HXMT observations of Swift J0243.6+6124: the evolution of RMS pulse fractions at super-Eddington luminosity

Author: Wang, P. J., Kong, L. D., Zhang, S., Chen, Y. P., Zhang, S. N., Qu, J. L., Ji, L., Tao, L., Ge, M. Y., Lu, F. J., Chen, L., Song, L. M., Li, T. P., Xu, Y. P., Cao, X. L., Chen, Y., Liu, C. Z., Bu, Q. C., Cai, C., Chang, Z., Chen, G., Chen, T. X., Chen, Y. B., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, J., Jin, Y. J., Li, B., Li, C. K., Li, G., Li, M. S., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, Q., Luo, T., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Sai, N., Shang, R. C., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, G. F., Wang, J., Wang, L. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, J. W., Yang, S., Yang, Yan Ji, Yang, Yi Jung, Yi, Q. B., Yin, Q. Q., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W. C., Zhang, W., Zhang, W. Z., Zhang, Y., Zhang, Y. F., Zhang, Y. J., Zhang, Zhao, Zhang, Zhi, Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., Zhou, D. K., Zhou, J. F., Zhu, Y. X., Zhu, Y., and Zhuang, R. L.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Based on Insight-HXMT data, we report on the pulse fraction evolution during the 2017-2018 outburst of the newly discovered first Galactic ultraluminous X-ray source (ULX) Swift J0243.6+6124. The pulse fractions of 19 observation pairs selected in the rising and fading phases with similar luminosity are investigated. The results show a general trend of the pulse fraction increasing with luminosity and energy at super-critical luminosity. However, the relative strength of the pulsation between each pair evolves strongly with luminosity. The pulse fraction in the rising phase is larger at luminosity below $7.71\times10^{38}$~erg~s$^{-1}$, but smaller at above. A transition luminosity is found to be energy independent. Such a phenomena is firstly confirmed by Insight-HXMT observations and we speculate it may have relation with the radiation pressure dominated accretion disk.
Published: 2020
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33. Physical origin of the nonphysical spin evolution of MAXI J1820+070

Author: Guan, J., Tao, L., Qu, J. L., Zhang, S. N., Zhang, W., Zhang, S., Ma, R. C., Ge, M. Y., Song, L. M., Lu, F. J., Li, T. P., Xu, Y. P., Chen, Y., Cao, X. L., Liu, C. Z., Zhang, L., Wang, Y. N., Chen, Y. P., Bu, Q. C., Cai, C., Chang, Z., Chen, L., Chen, T. X., Chen, Y. B., Cui, W. W., Du, Y. Y., Gao, G. H., Gao, H., Gu, Y. D., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, W., Li, X., Li, X. B., Li, X. F., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, H. W., Liu, H. X., Liu, X. J., Lu, X. F., Luo, Q., Luo, T., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Ren, X. Q., Sai, N., Song, X. Y., Sun, L., Tan, Y., Wang, C., Wang, L. J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, R. J., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, F., Zhang, H. M., Zhang, J., Zhang, P., Zhang, W. C., Zhang, Y. F., Zhang, Y. H., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, 83C57
Abstract: We report on the Insight-HXMT observations of the new black hole X-ray binary MAXI J1820+070 during its 2018 outburst. Detailed spectral analysis via the continuum fitting method shows an evolution of the inferred spin during its high soft sate. Moreover, the hardness ratio, the non-thermal luminosity and the reflection fraction also undergo an evolution, exactly coincident to the period when the inferred spin transition takes place. The unphysical evolution of the spin is attributed to the evolution of the inner disc, which is caused by the collapse of a hot corona due to condensation mechanism or may be related to the deceleration of a jet-like corona. The studies of the inner disc radius and the relation between the disc luminosity and the inner disc radius suggest that, only at a particular epoch, did the inner edge of the disc reach the innermost stable circular orbit and the spin measurement is reliable. We then constrain the spin of MAXI J1820+070 to be a*=0.2^{+0.2}_{-0.3}. Such a slowly spinning black hole possessing a strong jet suggests that its jet activity is driven mainly by the accretion disc rather than by the black hole spin., Comment: 14 pages, 13 figures, 5 tables, accepted for publication in MNRAS
Published: 2020
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34. X-ray reprocessing in accreting pulsar GX 301-2 observed with Insight-HXMT

Author: Ji, L., Doroshenko, V., Suleimanov, V., Santangelo, A., Orlandini, M., Liu, J., Ducci, L., Zhang, S. N., Nabizadeh, A., Gavran, D., Zhang, S., Ge, M. Y., Li, X. B., Tao, L., Bu, Q. C., Qu, J. L., Lu, F. J., Chen, L., Song, L. M., Li, T. P., Xu, Y. P., Cao, X. L., Chen, Y., Liu, C. Z., Cai, C., Chang, Z., Chen, T. X., Chen, Y. P., Cui, W. W., Du, Y. Y., Gao, G. H., Gao, H., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, W., Li, X., Li, X. F., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, H. X., Liu, H. W., Liu, X. J., Lu, X. F., Luo, Q., Luo, T., Ma, R. C., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Ren, X. Q., Sai, N., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, L. J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, R. J., Yang, S., Yang, Yan-Ji, Yang, Yi-Jung, Yi, Q. B., Yin, Q. Q., You, Y., Zhang, F., Zhang, H. M., Zhang, J., Zhang, P., Zhang, W., Zhang, W. C., Zhang, Yi, Zhang, Y. F., Zhang, Y. H., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We investigate the absorption and emission features in observations of GX 301-2 detected with Insight-HXMT/LE in 2017-2019. At different orbital phases, we found prominent Fe Kalpha, Kbeta and Ni Kalpha lines, as well as Compton shoulders and Fe K-shell absorption edges. These features are due to the X-ray reprocessing caused by the interaction between the radiation from the source and surrounding accretion material. According to the ratio of iron lines Kalpha and Kbeta, we infer the accretion material is in a low ionisation state. We find an orbital-dependent local absorption column density, which has a large value and strong variability around the periastron. We explain its variability as a result of inhomogeneities of the accretion environment and/or instabilities of accretion processes. In addition, the variable local column density is correlated with the equivalent width of the iron Kalpha lines throughout the orbit, which suggests that the accretion material near the neutron star is spherically distributed., Comment: 10 pages, 5 figures, 2 tables, accepted for publication in MNRAS
Published: 2020
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35. Insight-HXMT observations of a possible fast transition from jet to wind dominated state during a huge flare of GRS~1915+105

Author: Kong, L. D., Zhang, S., Chen, Y. P., Zhang, S. N., Ji, L., Wang, P. J., Tao, L., Ge, M. Y., Liu, C. Z., Song, L. M., Lu, F. J., Qu, J. L., Li, T. P., Xu, Y. P., Cao, X. L., Chen, Y., Bu, Q. C., Cai, C., Chang, Z., Chen, G., Chen, L., Chen, T. X., Cui, W. W., Du, Y. Y., Gao, G. H., Gao, H., Gao, M., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Li, B., Li, C. K., Li, G., Li, W., Li, X., Li, X. B., Li, X. F., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, H. W., Liu, H. X., Liu, X. J., Lu, X. F., Luo, Q., Luo, T., Ma, R. C., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Ren, X. Q., Sai, N., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, L. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, R. J., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, F., Zhang, H. M., Zhang, J., Zhang, P., Zhang, W. C., Zhang, W., Zhang, Y. F., Zhang, Y. H., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the analysis of the brightest flare that was recorded in the \emph{Insight}-HMXT data set, in a broad energy range (2$-$200 keV) from the microquasar GRS~1915+105 during an unusual low-luminosity state. This flare was detected by \emph{Insight}-HXMT among a series of flares during 2 June 2019 UTC 16:37:06 to 20:11:36, with a 2-200 keV luminosity of 3.4$-$7.27$\times10^{38}$ erg s$^{-1}$. Basing on the broad-band spectral analysis, we find that the flare spectrum shows different behaviors during bright and faint epochs. The spectrum of the flare can be fitted with a model dominated by a power-law component. Additional components show up in the bright epoch with a hard tail and in the faint epoch with an absorption line $\sim$ 6.78 keV. The reflection component of the latter is consistent with an inner disk radius $\sim$ 5 times larger than that of the former. These results on the giant flare during the "unusual" low-luminosity state of GRS~1915+105 may suggest that the source experiences a possible fast transition from a jet-dominated state to a wind-dominated state. We speculate that the evolving accretion disk and the large-scale magnetic field may play important roles in this peculiar huge flare.
Published: 2020
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36. A variable ionized disk wind in the black-hole candidate EXO 1846-031

Author: Wang, Yanan, Ji, Long, Garcia, Javier A., Dauser, Thomas, Mendez, Mariano, Mao, Junjie, Tao, L., Altamirano, Diego, Maggi, Pierre, Zhang, S. N., Ge, M. Y., Zhang, L., Qu, J. L., Zhang, S., Ma, X., Lu, F. J., Li, T. P., Huang, Y., Zheng, S. J., Chang, Z., Tuo, Y. L., Song, L. M., Xu, Y. P., Chen, Y., Liu, C. Z., Bu, Q. C., Cai, C., Cao, X. L., Chen, L., Chen, T. X., Chen, Y. P., Cui, W. W., Du, Y. Y., Gao, G. H., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, W., Li, X., Li, X. B., Li, X. F., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, H. W., Liu, X. J., Lu, X. F., Luo, Q., Luo, T., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Sai, N., Shang, R. C., Song, X. Y., Sun, L., Tan, Y., Wang, W. S., Wang, Y. D., Wang, Y. S., Wen, X. Y., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, F., Zhang, H. M., Zhang, J., Zhang, W. C., Zhang, W., Zhang, Y. F., Zhao, H. S., Zhao, X. F., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: After 34 years, the black-hole candidate EXO 1846-031 went into outburst again in 2019. We investigate its spectral properties in the hard intermediate and the soft states with NuSTAR and Insight-HXMT. A reflection component has been detected in the two spectral states but possibly originating from different illumination spectra: in the intermediate state, the illuminating source is attributed to a hard coronal component, which has been commonly observed in other X-ray binaries, whereas in the soft state the reflection is probably produced by the disk self-irradiation. Both cases support EXO 1846-031 as a low inclination system of ~40 degrees. An absorption line is clearly detected at ~7.2 keV in the hard intermediate state, corresponding to a highly ionized disk wind (log {\xi} > 6.1) with a velocity up to 0.06c. Meanwhile, quasi-simultaneous radio emissions have been detected before and after the X-rays, implying the co-existence of disk winds and jets in this system. Additionally, the observed wind in this source is potentially driven by magnetic forces. The absorption line disappeared in the soft state and a narrow emission line appeared at ~6.7 keV on top of the reflection component, which may be evidence for disk winds, but data with the higher spectral resolution are required to examine this., Comment: Accepted for publication in ApJ
Published: 2020
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37. The observation of the Crab Nebula with LHAASO-KM2A for the performance study

Author: Aharonian, F., An, Q., Axikegu, Bai, L. X., Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, H., Cai, J. T., Cao, Z., Chang, J., Chang, J. F., Chang, X. C., Chen, B. M., Chen, J., Chen, L., Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, X. L., Chen, Y., Cheng, N., Cheng, Y. D., Cui, S. W., Cui, X. H., Cui, Y. D., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Piazzoli, B. D'Ettorre, Dong, X. J., Fan, J. H., Fan, Y. Z., Fan, Z. X., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, Y. L., Gao, B., Gao, C. D., Gao, Q., Gao, W., Ge, M. M., Geng, L. S., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, J. G., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, J. C., He, S. L., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, C., Hou, X., Hu, H. B., Hu, S., Hu, S. C., Hu, X. J., Huang, D. H., Huang, Q. L., Huang, W. H., Huang, X. T., Huang, Z. C., Ji, F., Ji, X. L., Jia, H. Y., Jiang, K., Jiang, Z. J., Jin, C., Kuleshov, D., Levochkin, K., Li, B. B., Li, C., Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, K., Li, W. L., Li, X., Li, X. R., Li, Y., Li, Y. Z., Li, Z., Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. S., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y. N., Liu, Z. X., Long, W. J., Lu, R., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Masood, A., Mitthumsiri, W., Montaruli, T., Nan, Y. C., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Ruffolo, D., Rulev, V., Sáiz, A., Shao, L., Shchegolev, O., Sheng, X. D., Shi, J. R., Song, H. C., Stenkin, Yu. V., Stepanov, V., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Z. B., Tian, W. W., Wang, B. D., Wang, C., Wang, H., Wang, H. G., Wang, J. C., Wang, J. S., Wang, L. P., Wang, L. Y., Wang, R. N., Wang, W., Wang, X. G., Wang, X. J., Wang, X. Y., Wang, Y. D., Wang, Y. J., Wang, Y. P., Wang, Z., Wang, Z. H., Wang, Z. X., Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, W. X., Wu, X. F., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, G., Xiao, H. B., Xin, G. G., Xin, Y. L., Xing, Y., Xu, D. L., Xu, R. X., Xue, L., Yan, D. H., Yang, C. W., Yang, F. F., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Zeng, H. D., Zeng, T. X., Zeng, W., Zeng, Z. K., Zha, M., Zhai, X. X., Zhang, B. B., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, J. W., Zhang, L., Zhang, L. X., Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y., Zhang, Y. F., Zhang, Y. L., Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, Y., Zhou, B., Zhou, H., Zhou, J. N., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: As a sub-array of the Large High Altitude Air Shower Observatory (LHAASO), KM2A is mainly designed to cover a large fraction of the northern sky to hunt for gamma-ray sources at energies above 10 TeV. Even though the detector construction is still underway, a half of the KM2A array has been operating stably since the end of 2019. In this paper, we present the pipeline of KM2A data analysis and the first observation on the Crab Nebula, a standard candle in very high energy gamma-ray astronomy. We detect gamma-ray signals from the Crab Nebula in both energy ranges of 10$-$100 TeV and $>$100 TeV with high significance, by analyzing the KM2A data of 136 live days between December 2019 and May 2020. With the observations, we test the detector performance including angular resolution, pointing accuracy and cosmic ray background rejection power. The energy spectrum of the Crab Nebula in the energy range 10-250 TeV fits well with a single power-law function dN/dE =(1.13$\pm$0.05$_{stat}$$\pm$0.08$_{sys}$)$\times$10$^{-14}$$\cdot$(E/20TeV)$^{-3.09\pm0.06_{stat}\pm0.02_{sys}}$ cm$^{-2}$ s$^{-1}$ TeV$^{-1}$. It is consistent with previous measurements by other experiments. This opens a new window of gamma-ray astronomy above 0.1 PeV through which ultrahigh-energy gamma-ray new phenomena, such as cosmic PeVatrons, might be discovered., Comment: 13 pages, 15 figures,submitted to CPC
Published: 2020
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38. Constraining the transient high-energy activity of FRB180916.J0158+65 with Insight-HXMT followup observations

Author: Guidorzi, C., Orlandini, M., Frontera, F., Nicastro, L., Xiong, S. L., Liao, J. Y., Li, G., Zhang, S. N., Amati, L., Virgilli, E., Zhang, S., Bu, Q. C., Cai, C., Cao, X. L., Chang, Z., Chen, L., Chen, T. X., Chen, Y., Chen, Y. P., Cui, W. W., Du, Y. Y., Gao, G. H., Gao, H., Gao, M., Ge, M. Y., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, T. P., Li, W., Li, X., Li, X. B., Li, X. F., Li, Z. W., Liang, X. H., Liu, B. S., Liu, C. Z., Liu, H. X., Liu, H. W., Liu, X. J., Lu, F. J., Lu, X. F., Luo, Q., Luo, T., Ma, R. C., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Qu, J. L, Ren, X. Q., Sai, N., Song, L. M., Song, X. Y., Sun, L., Tan, Y., Tao, L., Tuo, Y. L., Wang, C., Wang, L. J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xu, Y. P., Yang, R., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, F., Zhang, H. M., Zhang, J., Zhang, P., Zhang, W. C., Zhang, W., Zhang, Y. F., Zhang, Y. H., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., and Zhou, D. K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: A link between magnetars and fast radio burst (FRB) sources has finally been established. In this context, one of the open issues is whether/which sources of extra galactic FRBs exhibit X/gamma-ray outbursts and whether it is correlated with radio activity. We aim to constrain possible X/gamma-ray burst activity from one of the nearest extragalactic FRB sources currently known over a broad energy range, by looking for bursts over a range of timescales and energies that are compatible with being powerful flares from extragalactic magnetars. We followed up the as-yet nearest extragalactic FRB source at a mere 149 Mpc distance, the periodic repeater FRB180916.J0158+65, during the active phase on February 4-7, 2020, with the Insight-Hard X-ray Modulation Telescope (HXMT). Taking advantage of the combination of broad band, large effective area, and several independent detectors available, we searched for bursts over a set of timescales from 1 ms to 1.024 s with a sensitive algorithm, that had previously been characterised and optimised. Moreover, through simulations we studied the sensitivity of our technique in the released energy-duration phase space for a set of synthetic flares and assuming different energy spectra. We constrain the possible occurrence of flares in the 1-100 keV energy band to E<10^46 erg for durations <0.1 s over several tens of ks exposure. We can rule out the occurrence of giant flares similar to the ones that were observed in the few cases of Galactic magnetars. The absence of reported radio activity during our observations does not allow us to make any statements on the possible simultaneous high-energy emission., Comment: 10 pages, 3 figures, accepted by A&A
Published: 2020
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39. Insight-HXMT firm detection of the highest energy fundamental cyclotron resonance scattering feature in the spectrum of GRO J1008-57

Author: Ge, M. Y., Ji, L., Zhang, S. N., Santangelo, A., Liu, C. Z., Doroshenko, V., Staubert, R., Qu, J. L., Zhang, S., Lu, F. J., Song, L. M., Li, T. P., Tao, L., Xu, Y. P., Cao, X. L., Chen, Y., Bu, Q. C., Cai, C., Chang, Z., Chen, G., Chen, L., Chen, T. X., Chen, Y. B., Chen, Y. P., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, J., Jin, Y. J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, M. S., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, Q., Luo, T., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Sai, N., Shang, R. C., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, G. F., Wang, J., Wang, L. J., Wang, W. S., Wang, Y. D., Wang, Y. S., Wen, X. Y., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Xu, H., Yang, J. W., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W. C., Zhang, W., Zhang, W. Z., Zhang, Y., Zhang, Y. F., Zhang, Y. J., Zhang, Z., Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., Zhou, D. K., Zhou, J. F., Zhuang, R. L., Zhu, Y. X., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the observation of the accreting pulsar GRO J1008-57 performed by Insight-HXMT at the peak of the source's 2017 outburst. Pulsations are detected with a spin period of 93.283(1) s. The pulse profile shows double peaks at soft X-rays, and only one peak above 20 keV. The spectrum is well described by the phenomenological models of X-ray pulsars. A cyclotron resonant scattering feature is detected with very high statistical significance at a centroid energy of $E_{\rm cyc}=90.32_{-0.28}^{+0.32}$ keV, for the reference continuum and line models, HIGHECUT and GABS respectively. Detection is very robust with respect to different continuum models. The line energy is significantly higher than what suggested from previous observations, which provided very marginal evidence for the line. This establishes a new record for the centroid energy of a fundamental cyclotron resonant scattering feature observed in accreting pulsars. We also discuss the accretion regime of the source during the Insight-HXMT observation., Comment: 8 pages, 3 figures, accepted for publication in ApJL
Published: 2020
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40. On the Distance of SGR 1935+2154 Associated with FRB 200428 and Hosted in SNR G57.2+0.8

Author: Zhong, S. Q., Dai, Z. G., Zhang, H. M., and Deng, C. M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Owing to the detection of an extremely bright fast radio burst (FRB) 200428 associated with a hard X-ray counterpart from the magnetar soft gamma-ray repeater (SGR) 1935+2154, the distance of SGR 1935+2154 potentially hosted in the supernova remnant (SNR) G57.2+0.8 can be revisited. Under the assumption that the SGR and the SNR are physically related, in this Letter, by investigating the dispersion measure (DM) of the FRB contributed by the foreground medium of our Galaxy and the local environments and combining with other observational constraints, we find that the distance of SGR 1935+2154 turns out to be $9.0\pm2.5\,$kpc and the SNR radius falls into $10$ to $18\,$pc since the local DM contribution is as low as $0-18\,$pc cm$^{-3}$. These results are basically consistent with the previous studies. In addition, an estimate for the Faraday rotation measure of the SGR and SNR is also carried out., Comment: 7 pages, 3 figures (replotted), an uncertainty analysis of the distance estimate has been added, accepted for publication in ApJ Letters
Published: 2020
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41. HXMT Identification of a non-thermal X-ray burst from SGR J1935+2154 and with FRB 200428

Author: Li, C. K., Lin, L., Xiong, S. L., Ge, M. Y., Li, X. B., Li, T. P., Lu, F. J., Zhang, S. N., Tuo, Y. L., Nang, Y., Zhang, B., Xiao, S., Chen, Y., Song, L. M., Xu, Y. P., Liu, C. Z., Jia, S. M., Cao, X. L., Qu, J. L., Zhang, S., Gu, Y. D., Liao, J. Y., Zhao, X. F., Tan, Y., Nie, J. Y., Zhao, H. S., Zheng, S. J., Zheng, Y. G., Luo, Q., Cai, C., Li, B., Xue, W. C., Bu, Q. C., Chang, Z., Chen, G., Chen, T. X., Chen, Y. B., Chen, Y. P., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jiang, L. H., Jiang, W. C., Jin, J., Jin, Y. J., Kong, L. D., Li, G., Li, M. S., Li, W., Li, X., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liu, B. S., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, T., Ma, X., Meng, B., Ou, G., Sai, N., Shang, R. C., Song, X. Y., Sun, L., Tao, L., Wang, C., Wang, G. F., Wang, J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xu, H., Yang, J. W., Yang, S., Yang, Y. J., Yang, Yi-Jung, Yi, Q. B., Yin, Q. Q., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W., Zhang, W. C., Zhang, W. Z., Zhang, Y., Zhang, Yue, Zhang, Y. F., Zhang, Y. J., Zhang, Z., Zhang, Zhi, Zhang, Z. L., Zhou, D. K., Zhou, J. F., Zhu, Y., Zhu, Y. X., and Zhuang, R. L.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Fast radio bursts (FRBs) are short pulses observed in radio band from cosmological distances. One class of models invoke soft gamma-ray repeaters (SGRs), or magnetars, as the sources of FRBs. Some radio pulses have been observed from some magnetars, however, no FRB-like events had been detected in association any magnetar burst, including one giant flare. Recently, a pair of FRB-like bursts (FRB 200428 hereafter) separated by milliseconds (ms) were detected from the general direction of the Galactic magnetar SGR J1935+2154. Here we report the detection of a non-thermal X-ray burst in the 1-250 keV energy band with the Insight-HXMT satellite, which we identify as emitted from SGR J1935+2154. The burst showed two hard peaks with a separation of 34 ms, broadly consistent with that of the two bursts in FRB 200428. The delay time between the double radio and X-ray peaks is about 8.57 s, fully consistent with the dispersion delay of FRB 200428. We thus identify the non-thermal X-ray burst is associated with FRB 200428 whose high energy counterpart is the two hard peaks in X-ray. Our results suggest that the non-thermal X-ray burst and FRB 200428 share the same physical origin in an explosive event from SGR J1935+2154., Comment: 24 pages, 9 figures, 6 tables; initial submission to a journal on May 9th, 2020. Significant changes include updated localization and detailed spectral evolution of the X-ray burst, and better determination of the two narrow X-ray peaks corresponding to the two radio pulses. Conclusions are strengthened. Nature Astronomy online on Feb. 18, 2021
Published: 2020
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42. Insight-HXMT insight into switch of the accretion mode: the case of the X-ray pulsar 4U 1901+03

Author: Tuo, Y. L., Ji, L., Tsygankov, S. S., Mihara, T., Song, L. M., Ge, M. Y., Nabizadeh, A., Tao, L., Qu, J. L., Zhang, Y., Zhang, S., Zhang, S. N., Bu, Q. C., Chen, L., Xu, Y. P., Cao, X. L., Chen, Y., Liu, C. Z., Cai, C., Chang, Z., Chen, G., Chen, T. X., Chen, Y. B., Chen, Y. P., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, J., Jin, Y. J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, M. S., Li, T. P., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, B. S., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, F. J., Lu, X. F., Luo, Q., Luo, T., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Sai, N., Shang, R. C., Song, X. Y., Sun, L., Tan, Y., Wang, C., Wang, G. F., Wang, J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, J. W., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W., Zhang, W. C., Zhang, W. Z., Zhang, Y. F., Zhang, Y. J., Zhang, Y. H., Zhang, Z., Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., Zhou, D. K., Zhou, J. F., Zhu, Y. X., Zhu, Y., and Zhuang, R. L.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We use the In data collected during the 2019 outburst from X-ray pulsar 4U 1901+03 to complement the orbital parameters reported by Fermi/GBM. Using the Insight-HXMT, we examine the correlation between the derivative of the intrinsic spin frequency and bolometric flux based on accretion torque models. It was found that the pulse profiles significantly evolve during the outburst. The existence of two types of the profile's pattern discovered in the Insight-HXMT data indicates that this source experienced transition between a super-critical and a sub-critical accretion regime during its 2019 outburst. Based on the evolution of the pulse profiles and the torque model, we derive the distance to 4U 1901+03 as 12.4+-0.2 kpc., Comment: 8 pages, 5 figures, accepted by JHEAP
Published: 2020

43. The evolution of the broadband temporal features observed in the black-hole transient MAXI J1820+070 with Insight-HXMT

Author: Wang, Yanan, Ji, Long, Zhang, S. N., Méndez, Mariano, Qu, J. L., Maggi, Pierre, Ge, M. Y., Qiao, Erlin, Tao, L., Zhang, S., Altamirano, Diego, Zhang, L., Ma, X., Lu, F. J., Li, T. P., Huang, Y., Zheng, S. J., Chen, Y. P., Chang, Z., Tuo, Y. L., Gungor, C., Song, L. M., Xu, Y. P., Cao, X. L., Chen, Y., Liu, C. Z., Bu, Q. C., Cai, C., Chen, G., Chen, L., Chen, T. X., Chen, Y. B., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huo, J., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, J., Jin, Y. J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, M. S., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, Q., Luo, T., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Sai, N., Shang, R. C., Song, X. Y., Sun, L., Tan, Y., Wang, G. F., Wang, J., Wang, W. S., Wang, Y. D., Wang, Y. S., Wen, X. Y., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, J. W., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W. C., Zhang, W., Zhang, W. Z., Zhang, Y., Zhang, Y. F., Zhang, Y. J., Zhang, Z., Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zhou, D. K., Zhou, J. F., Zhuang, R. L., Zhu, Y. X., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We study the evolution of the temporal properties of MAXI 1820+070 during the 2018 outburst in its hard state from MJD 58190 to 58289 with Insight-HXMT in a broad energy band 1-150 keV. We find different behaviors of the hardness ratio, the fractional rms and time lag before and after MJD 58257, suggesting a transition occurred at around this point. The observed time lags between the soft photons in the 1-5 keV band and the hard photons in higher energy bands, up to 150 keV, are frequency-dependent: the time lags in the low-frequency range, 2-10 mHz, are both soft and hard lags with a timescale of dozens of seconds but without a clear trend along the outburst; the time lags in the high-frequency range, 1-10 Hz, are only hard lags with a timescale of tens of milliseconds; first increase until around MJD 58257 and decrease after this date. The high-frequency time lags are significantly correlated to the photon index derived from the fit to the quasi-simultaneous NICER spectrum in the 1-10 keV band. This result is qualitatively consistent with a model in which the high-frequency time lags are produced by Comptonization in a jet., Comment: Accepted for publication in ApJ
Published: 2020
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44. Discovery of delayed spin-up behavior following two large glitches in the Crab pulsar, and the statistics of such processes

Author: Ge, M. Y., Zhang, S. N., Lu, F. J., Li, T. P., Yuan, J. P., Zheng, X. P., Huang, Y., Zheng, S. J., Chen, Y. P., Chang, Z., Tuo, Y. L., Cheng, Q., Güngör, C., Song, L. M., Xu, Y. P., Cao, X. L., Chen, Y., Liu, C. Z., Zhang, S., Qu, J. L., Bu, Q. C., Cai, C., Chen, G., Chen, L., Chen, M. Z., Chen, T. X., Chen, Y. B., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Hao, L. F., Huo, J., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, C. J., Jin, J., Jin, Y. J., Kong, L. D., Li, B., Li, D., Li, C. K., Li, G., Li, M. S., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Li, Z. X., Liu, Z. Y., Liang, X. H., Liao, J. Y., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, Q., Luo, T., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Sai, N., Shang, R. C., Song, X. Y., Sun, L., Tan, Y., Tao, L., Wang, C., Wang, G. F., Wang, J., Wang, J. B., Wang, M., Wang, N., Wang, W. S., Wang, Y. D., Wang, Y. S., Wen, X. Y., Wen, Z. G., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Xu, Y. H., Yan, W. M., Yang, J. W., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Yue, Y. L., Zhang, A. M., Zhang, C. M., Zhang, D. P., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W. C., Zhang, W., Zhang, W. Z., Zhang, Y., Zhang, Y. F., Zhang, Y. J., Zhang, Z., Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zheng, W., Zhou, D. K., Zhou, J. F., Zhou, X., Zhuang, R. L., Zhu, Y. X., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Glitches correspond to sudden jumps of rotation frequency ($\nu$) and its derivative ($\dot{\nu}$) of pulsars, the origin of which remains not well understood yet, partly because the jump processes of most glitches are not well time-resolved. There are three large glitches of the Crab pulsar, detected in 1989, 1996 and 2017, which were found to have delayed spin-up processes before the normal recovery processes. Here we report two additional glitches of the Crab pulsar occurred in 2004 and 2011 for which we discovered delayed spin up processes, and present refined parameters of the largest glitch occurred in 2017. The initial rising time of the glitch is determined as $<0.48$ hour. We also carried out a statistical study of these five glitches with observed spin-up processes. The two glitches occurred in 2004 and 2011 have delayed spin-up time scales ($\tau_{1}$) of $1.7\pm0.8$\,days and $1.6\pm0.4$\,days, respectively. We find that the $\Delta{\nu}$ vs. $|\Delta{\dot\nu}|$ relation of these five glitches is similar to those with no detected delayed spin-up process, indicating that they are similar to the others in nature except that they have larger amplitudes. For these five glitches, the amplitudes of the delayed spin-up process ($|\Delta{\nu}_{\rm d1}|$) and recovery process ($\Delta{\nu}_{\rm d2}$), their time scales ($\tau_{1}$, $\tau_{2}$), and permanent changes in spin frequency ($\Delta{\nu}_{\rm p}$) and total frequency step ($\Delta{\nu}_{\rm g}$) have positive correlations. From these correlations, we suggest that the delayed spin-up processes are common for all glitches, but are too short and thus difficult to be detected for most glitches., Comment: 25 pages, 8 figures
Published: 2020
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45. A search for prompt gamma-ray counterparts to fast radio bursts in the Insight-HXMT data

Author: Guidorzi, C., Marongiu, M., Martone, R., Nicastro, L., Xiong, S. L., Liao, J. Y., Li, G., Zhang, S. N., Amati, L., Frontera, F., Orlandini, M., Rosati, P., Virgilli, E., Zhang, S., Bu, Q. C., Cai, C., Cao, X. L., Chang, Z., Chen, G., Chen, L., Chen, T. X., Chen, Y. B., Chen, Y. P., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Ge, M. Y., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, J., Jin, Y. J., Kong, L. D., Li, B., Li, C. K., Li, M. S., Li, T. P., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liu, B. S., Liu, C. Z., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, F. J., Lu, X. F., Luo, Q., Luo, T., Ma, R. C., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Oui, G., Qu, J. L, Sai, N., Shang, R. C., Song, L. M., Song, X. Y., Sun, L., Tani, Y., Tao, L., Tuo, Y. L., Wang, C., Wang, G. F., Wang, J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xu, Y. P., Yang, J. W., Yang, S., Yang, Y. J., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, A. M. Zhang C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W. C., Zhang, W., Zhang, W. Z., Zhang, Y., Zhang, Y. F., Zhang, Y. J., Zhang, Z., Zhang, Z. L., Zhang, H. S., Zhang, X. F., Zheng, S. J., Zhou, D. K., Zhou, J. F., Zhu, Y. X., Zhu, Y., and Zhuang, R. L.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: No robust detection of prompt electromagnetic counterparts to fast radio bursts (FRBs) has yet been obtained, in spite of several multi-wavelength searches carried out so far. Specifically, X/gamma-ray counterparts are predicted by some models. We planned on searching for prompt gamma-ray counterparts in the Insight-Hard X-ray Modulation Telescope (Insight-HXMT) data, taking advantage of the unique combination of large effective area in the keV-MeV energy range and of sub-ms time resolution. We selected 39 FRBs that were promptly visible from the High-Energy (HE) instrument aboard Insight-HXMT. After calculating the expected arrival times at the location of the spacecraft, we searched for a significant excess in both individual and cumulative time profiles over a wide range of time resolutions, from several seconds down to sub-ms scales. Using the dispersion measures in excess of the Galactic terms, we estimated the upper limits on the redshifts. No convincing signal was found and for each FRB we constrained the gamma-ray isotropic-equivalent luminosity and the released energy as a function of emission timescale. For the nearest FRB source, the periodic repeater FRB180916.J0158+65, we find $L_{\gamma,iso}<5.5\times 10^{47}$ erg/s over 1 s, whereas $L_{\gamma,iso}<10^{49}-10^{51}$ erg/s for the bulk of FRBs. The same values scale up by a factor of ~100 for a ms-long emission. Even on a timescale comparable with that of the radio pulse itself no keV-MeV emission is observed. A systematic association with either long or short GRBs is ruled out with high confidence, except for subluminous events, as is the case for core-collapse of massive stars (long) or binary neutron star mergers (short) viewed off axis. Only giant flares from extra-galactic magnetars at least ten times more energetic than Galactic siblings are ruled out for the nearest FRB., Comment: 15 pages, 3 figures, 6 tables, accepted by A&A
Published: 2020
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46. Switches between accretion structures during flares in 4U 1901+03

Author: Ji, L., Ducci, L., Santangelo, A., Zhang, S., Suleimanov, V., Tsygankov, S., Doroshenko, V., Nabizadeh, A., Zhang, S. N., Ge, M. Y., Tao, L., Bu, Q. C., Qu, J. L., Lu, F. J., Chen, L., Song, L. M., Li, T. P., Xu, Y. P., Cao, X. L., Chen, Y., Liu, C. Z., Cai, C., Chang, Z., Chen, G., Chen, T. X., Chen, Y. B., Chen, Y. P., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, M. S., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, G. Q., Liu, H. X., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, Q., Luo, T., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Ren, X. Q., Sai, N., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, G. F., Wang, J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Yang, J. W., Yang, S., Yang, Yan-Ji, Yang, Yi-Jung, Yi, Q. B., Yin, Q. Q., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, P., Zhang, T., Zhang, W., Zhang, W. C., Zhang, W. Z., Zhang, Yi, Zhang, Y. F., Zhang, Y. J., Zhang, Y. H., Zhang, Yue, Zhang, Z., Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zhou, D. K., Zhou, J. F., Zhu, Y. X., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on our analysis of the 2019 outburst of the X-ray accreting pulsar 4U 1901+03 observed with Insight-HXMT and NICER. Both spectra and pulse profiles evolve significantly in the decaying phase of the outburst. Dozens of flares are observed throughout the outburst. They are more frequent and brighter at the outburst peak. We find that the flares, which have a duration from tens to hundreds of seconds, are generally brighter than the persistent emission by a factor of $\sim$ 1.5. The pulse profile shape during the flares can be significantly different than that of the persistent emission. In particular, a phase shift is clearly observed in many cases. We interpret these findings as direct evidence of changes of the pulsed beam pattern, due to transitions between the sub- and super-critical accretion regimes on a short time scale. We also observe that at comparable luminosities the flares' pulse profiles are rather similar to those of the persistent emission. This indicates that the accretion on the polar cap of the neutron star is mainly determined by the luminosity, i.e., the mass accretion rate., Comment: 11 pages, 8 figures, accepted for publication in MNRAS
Published: 2020
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47. Joint Analysis of Energy and RMS Spectra from MAXI J1535-571 with Insight-HXMT

Author: Kong, L. D., Zhang, S., Chen, Y. P., Ji, L., Zhang, S. N., Yang, Y. R., Tao, L., Ma, X., Qu, J. L., Lu, F. J., Bu, Q. C., Chen, L., Song, L. M., Li, T. P., Xu, Y. P., Cao, X. L., Chen, Y., Liu, C. Z., Cai, C., Chang, Z., Chen, G., Chen, T. X., Chen, Y. B., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Ge, M. Y., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, J., Li, B., Li, C. K., Li, G., Li, M. S., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, G. Q., Liu, H. X., Liu, H. W., Liu, S. Z., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, Q., Luo, T., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Ren, X. Q., Sai, N., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, G. F., Wang, J., Wang, P. J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Xu, H., Yang, J. W., Yang, S., Yang, Y. J., Yi, Q. B., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, P., Zhang, T., Zhang, W., Zhang, W. C., Zhang, W. Z., Zhang, Y., Zhang, Y. F., Zhang, Y. J., Zhang, Y. H., Zhang, Z., Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zheng, Y. G., Zhou, D. K., Zhou, J. F., Zhu, Y. X., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: A new black hole X-ray binary (BHXRB) MAXI J1535-571 was discovered by MAXI during its outburst in 2017. Using observations taken by the first Chinese X-ray satellite, the Hard X-ray Modulation Telescope (dubbed as Insight-HXMT), we perform a joint spectral analysis (2-150 keV) in both energy and time domains. The energy spectra provide the essential input for probing the intrinsic Quasi-Periodic Oscillation (QPO) fractional rms spectra (FRS). Our results show that during the intermediate state, the energy spectra are in general consistent with those reported by Swift/XRT and NuSTAR. However, the QPO FRS become harder and the FRS residuals may suggest the presence of either an additional power-law component in the energy spectrum or a turn-over in the intrinsic QPO FRS at high energies.
Published: 2020

48. Diagnostic of the spectral properties of Aquila X-1 by Insight-HXMT snapshots during the early propeller phase

Author: Güngör, C., Ge, M. Y., Zhang, S., Santangelo, A., Zhang, S. N., Lu, F. J., Zhang, Y., Chen, Y. P., Tao, L., Yang, Y. J., Bu, Q. C., Cai, C., Cao, X. L., Chang, Z., Chen, G., Chen, L., Chen, T. X., Chen, Y., Chen, Y. B., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huang, Y., Huo, J., Ji, L., Jia, S. M., Jiang, L. H., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, M. S., Li, T. P., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, C. Z., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, T., Luo, Q., Ma, X., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Sai, N., Song, L. M., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, G. F., Wang, J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. B., Wu, B. Y., Wu, M., Xiao, G. C., Xiao, S., Xiong, S. L., Xu, Y. P., Yang, J. W., Yang, S., Yi, Q. B., Yin, Q. Q., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W., Zhang, W. C., Zhang, W. Z., Zhang, Y. F., Zhang, Y. J., Zhang, Z., Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zhou, D. K., Zhou, J. F., Zhu, Y., and Zhu, Y. X.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We study the 2018 outburst of Aql X-1 via the monitor of all sky X-ray image (MAXI) data. We show that the outburst starting in February 2018 is a member of short-low class in the frame of outburst duration and the peak count rate although the outburst morphology is slightly different from the other fast-rise-exponential-decay (FRED) type outbursts with a milder rising stage. We study the partial accretion in the weak propeller stage of Aql X-1 via the MAXI data of the 2018 outburst. We report on the spectral analysis of 3 observations of Aquila X-1 obtained by Insight - hard X-ray modulation telescope (Insight-HXMT) during the late decay stage of the 2018 outburst. We discuss that the data taken by Insight-HXMT is just after the transition to the weak propeller stage. Our analysis shows the necessity of a comptonization component to take into account the existence of an electron cloud resulting photons partly up-scattered., Comment: 8 pages, 4 figures, accepted for publication in JHEAp
Published: 2019

49. Reconstruction of Cherenkov image by multiple telescopes of LHAASO-WFCTA

Author: Aharonian, F., An, Q., Axikegu, Bai, L. X., Bai, Y. X., Bao, Y. W., Bastieri, D., Bi, X. J., Bi, Y. J., Cai, J. T., Cao, Zhe, Cao, Zhen, Chang, J., Chang, J. F., Chen, E. S., Chen, Liang, Chen, Liang, Chen, Long, Chen, M. J., Chen, M. L., Chen, Q. H., Chen, S. H., Chen, S. Z., Chen, T. L., Chen, Y., Cheng, H. L., Cheng, N., Cheng, Y. D., Cui, S. W., Cui, X. H., Cui, Y. D., D’Ettorre Piazzoli, B., Dai, B. Z., Dai, H. L., Dai, Z. G., Danzengluobu, della Volpe, D., Duan, K. K., Fan, J. H., Fan, Y. Z., Fan, Z. X., Fang, J., Fang, K., Feng, C. F., Feng, L., Feng, S. H., Feng, X. T., Feng, Y. L., Gao, B., Gao, C. D., Gao, L. Q., Gao, Q., Gao, W., Gao, W. K., Ge, M. M., Geng, L. S., Gong, G. H., Gou, Q. B., Gu, M. H., Guo, F. L., Guo, J. G., Guo, X. L., Guo, Y. Q., Guo, Y. Y., Han, Y. A., He, H. H., He, H. N., He, S. L., He, X. B., He, Y., Heller, M., Hor, Y. K., Hou, C., Hou, X., Hu, H. B., Hu, Q., Hu, S., Hu, S. C., Hu, X. J., Huang, D. H., Huang, W. H., Huang, X. T., Huang, X. Y., Huang, Y., Huang, Z. C., Ji, X. L., Jia, H. Y., Jia, K., Jiang, K., Jiang, Z. J., Jin, M., Kang, M. M., Ke, T., Kuleshov, D., Levochkin, K., Li, B. B., Li, Cheng, Li, Cong, Li, F., Li, H. B., Li, H. C., Li, H. Y., Li, J., Li, Jian, Li, Jie, Li, K., Li, W. L., Li, X. R., Li, Xin, Li, Xin, Li, Y. Z., Li, Zhe, Li, Zhuo, Liang, E. W., Liang, Y. F., Lin, S. J., Liu, B., Liu, C., Liu, D., Liu, H., Liu, H. D., Liu, J., Liu, J. L., Liu, J. S., Liu, J. Y., Liu, M. Y., Liu, R. Y., Liu, S. M., Liu, W., Liu, Y., Liu, Y. N., Long, W. J., Lu, R., Luo, Q., Lv, H. K., Ma, B. Q., Ma, L. L., Ma, X. H., Mao, J. R., Masood, A., Min, Z., Mitthumsiri, W., Nan, Y. C., Ou, Z. W., Pang, B. Y., Pattarakijwanich, P., Pei, Z. Y., Qi, M. Y., Qi, Y. Q., Qiao, B. Q., Qin, J. J., Ruffolo, D., Sáiz, A., Shao, C. Y., Shao, L., Shchegolev, O., Sheng, X. D., Shi, J. Y., Song, H. C., Stenkin, Yu. V., Stepanov, V., Su, Y., Sun, Q. N., Sun, X. N., Sun, Z. B., Tam, P. H. T., Tang, Z. B., Tian, W. W., Wang, B. D., Wang, C., Wang, H., Wang, H. G., Wang, J. C., Wang, J. S., Wang, L. P., Wang, L. Y., Wang, R., Wang, R. N., Wang, W., Wang, X. G., Wang, X. Y., Wang, Y., Wang, Y. D., Wang, Y. J., Wang, Y. P., Wang, Z. H., Wang, Z. X., Wang, Zhen, Wang, Zheng, Wei, D. M., Wei, J. J., Wei, Y. J., Wen, T., Wu, C. Y., Wu, H. R., Wu, S., Wu, X. F., Wu, Y. S., Xi, S. Q., Xia, J., Xia, J. J., Xiang, G. M., Xiao, D. X., Xiao, G., Xin, G. G., Xin, Y. L., Xing, Y., Xiong, Z., Xu, D. L., Xu, R. X., Xue, L., Yan, D. H., Yan, J. Z., Yang, C. W., Yang, F. F., Yang, H. W., Yang, J. Y., Yang, L. L., Yang, M. J., Yang, R. Z., Yang, S. B., Yao, Y. H., Yao, Z. G., Ye, Y. M., Yin, L. Q., Yin, N., You, X. H., You, Z. Y., Yu, Y. H., Yuan, Q., Yue, H., Zeng, H. D., Zeng, T. X., Zeng, W., Zeng, Z. K., Zha, M., Zhai, X. X., Zhang, B. B., Zhang, F., Zhang, H. M., Zhang, H. Y., Zhang, J. L., Zhang, L. X., Zhang, Li, Zhang, Lu, Zhang, P. F., Zhang, P. P., Zhang, R., Zhang, S. B., Zhang, S. R., Zhang, S. S., Zhang, X., Zhang, X. P., Zhang, Y. F., Zhang, Y. L., Zhang, Yi, Zhang, Yong, Zhao, B., Zhao, J., Zhao, L., Zhao, L. Z., Zhao, S. P., Zheng, F., Zheng, Y., Zhou, B., Zhou, H., Zhou, J. N., Zhou, P., Zhou, R., Zhou, X. X., Zhu, C. G., Zhu, F. R., Zhu, H., Zhu, K. J., and Zuo, X.
Published: 2022
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50. $Insight$-HXMT study of the timing properties of Sco X-1

Author: Jia, S. M., Bu, Q. C., Qu, J. L., Lu, F. J., Zhang, S. N., Huang, Y., Ma, X., Tao, L., Xiao, G. C., Zhang, W., Chen, L., Song, L. M., Zhang, S., Li, T. B., Xu, Y. P., Cao, X. L., Chen, Y., Liu, C. Z., Cai, C., Chang, Z., Chen, G., Chen, T. X., Chen, Y. B., Chen, Y. P., Cui, W., Cui, W. W., Deng, J. K., Dong, Y. W., Du, Y. Y., Fu, M. X., Gao, G. H., Gao, H., Gao, M., Ge, M. Y., Gu, Y. D., Guan, J., Guo, C. C., Han, D. W., Huo, J., Jiang, L. H., Jiang, W. C., Jin, J., Kong, L. D., Li, B., Li, C. K., Li, G., Li, M. S., Li, W., Li, X., Li, X. B., Li, X. F., Li, Y. G., Li, Z. W., Liang, X. H., Liao, J. Y., Liu, G. Q., Liu, H. W., Liu, X. J., Liu, Y. N., Lu, B., Lu, X. F., Luo, Q., Luo, T., Meng, B., Nang, Y., Nie, J. Y., Ou, G., Sai, N., Song, X. Y., Sun, L., Tan, Y., Tuo, Y. L., Wang, C., Wang, G. F., Wang, J., Wang, W. S., Wang, Y. S., Wen, X. Y., Wu, B. Y., Wu, B. B., Wu, M., Xiao, S., Xiong, S. L., Yang, J. W., Yang, S., Yang, Y. J., Yin, Q. Q., Yi, Q. B., You, Y., Zhang, A. M., Zhang, C. M., Zhang, F., Zhang, H. M., Zhang, J., Zhang, T., Zhang, W. C., Zhang, W. Z., Zhang, Y., Zhang, Y. F., Zhang, Y. J., Zhang, Z., Zhang, Z. L., Zhao, H. S., Zhao, X. F., Zheng, S. J., Zhou, D. K., Zhou, J. F., Zhu, Y. X., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology
Abstract: We present a detailed timing study of the brightest persistent X-ray source Sco X-1 using the data collected by the Hard X-ray Modulation Telescope ($Insight$-HXMT) from July 2017 to August 2018. A complete $Z$-track hardness-intensity diagram (HID) is obtained. The normal branch oscillations (NBOs) at $\sim$ 6 Hz in the lower part of the normal branch (NB) and the flare branch oscillations (FBOs) at $\sim$ 16 Hz in the beginning part of the flaring branch (FB) are found in observations with the Low Energy X-ray Telescope (LE) and the Medium Energy X-ray Telescope (ME) of $Insight$-HXMT, while the horizontal branch oscillations (HBOs) at $\sim$ 40 Hz and the kilohertz quasi-periodic oscillations (kHz QPOs) at $\sim$ 800 Hz are found simultaneously up to 60 keV for the first time on the horizontal branch (HB) by the High Energy X-ray Telescope (HE) and ME. We find that for all types of the observed QPOs, the centroid frequencies are independent of energy, while the root mean square (rms) increases with energy; the centroid frequencies of both the HBOs and kHz QPOs increase along the $Z$-track from the top to the bottom of the HB; and the NBOs show soft phase lags increasing with energy. A continuous QPO transition from the FB to NB in $\sim$ 200 s are also detected. Our results indicate that the non-thermal emission is the origin of all types of QPOs, the innermost region of the accretion disk is non-thermal in nature, and the corona is nonhomogeneous geometrically.
Published: 2019

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