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Your search keyword '"G H Gao"' showing total 22 results
Start Over Author "G H Gao" Topic 010303 astronomy & astrophysics
22 results on '"G H Gao"'

1. Accretion torque reversals in GRO J1008-57 revealed by Insight-HXMT

Author

Prahlad Epili, ShiJie Zheng, Yuan-Yuan Du, Peng Zhang, W. C. Jiang, Y. M. Tang, T. Luo, C. Z. Liu, S. Yang, Y. B. Chen, Xin Ren, Xufang Li, Gang Li, Cheng-Cheng Guo, Y. J. Yang, N. Sai, W. S. Wang, Wei Wang, Lei Sun, Zhe Chang, W. G. Li, X.W. Ma, L. D. Kong, Q. Luo, Bin Meng, Y. S. Wang, Jin-Yuan Liao, X. L. Cao, Da-Wei Han, Lian Tao, L. Wang, Tianran Chen, Y. G. Zheng, C. Cai, Xiong Li, Yu-Dong Gu, G. H. Gao, Mingyu Wu, Ming-Yu Ge, Y. Huang, B. Y. Wu, Weiguang Cui, Qingcui Bu, J. J. Yang, He-Yang Liu, L. Chen, Xiaohua Liang, Yuan You, X. Y. Song, R. C. Ma, Shuo Xiao, D. K. Zhou, Youli Tuo, Yi Zhang, He Gao, Jin-Lu Qu, Shaolin Xiong, Xuchao Zhao, Bing Li, Ju Guan, R. J. Yang, F. Zhang, B. B. Yi, H. M. Zhang, Jing Jin, X. F. Li, Wenda Zhang, Bobing Wu, Ti-Pei Li, Li-Ming Song, C. Wang, Junqiang Zhang, Bai-Sheng Liu, C. K. Li, Fangjun Lu, Shuang-Nan Zhang, G. C. Xiao, W. C. Zhang, Jundan Nie, Hongwei Liu, HongSheng Zhao, S. N. Zhang, Q. Q. Yin, Y. P. Chen, Y. Nang, P. J. Wang, Shu-Mei Jia, Ge Ou, Yin Xu, Jia Huo, X. Y. Wen, Z. W. Li, and Xin Lu

Subjects
Physics, Accretion (meteorology), Magnetic moment, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics, Radius, 01 natural sciences, Magnetic field, Neutron star, Dipole, Pulsar, Space and Planetary Science, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Line (formation)
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 ± 0.05 ) × 10−4 s/d from 2009 – 2018, and turned into a spin down process with a rate of ( 6.7 ± 0.6 ) × 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 Alfven 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 ≥ 6 × 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.

Published
2021
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2. HXMT identification of a non-thermal X-ray burst from SGR J1935+2154 and with FRB 200428

Author

Y. J. Jin, Z. Chang, J. Y. Liao, H. M. Zhang, Y. F. Zhang, X. B. Li, Y. G. Li, Chun-sheng Zhang, Wenhan Jiang, Bo Li, Yu-Xuan Zhu, G. H. Gao, J. Jin, M. Wu, Y. Zhang, Xin-Fu Zhao, Zhi Zhang, Y. H. Tan, Y. X. Zhu, R. C. Shang, C. Cai, B. Lu, Fuqin Zhang, J. K. Deng, S. N. Zhang, W. C. Xue, X. X. Li, Y. G. Zheng, J. F. Zhou, Ming-Yu Ge, X. H. Ma, Wenxiong Li, Tian-Xiang Chen, F. J. Lu, Y. S. Wang, D. K. Zhou, Wei Cui, T. Zhang, Aimei Zhang, Lin Lin, Li-Ming Song, B. S. Liu, Lei Sun, C. Z. Liu, S. J. Zheng, Luhua Jiang, Y. P. Xu, B. B. Wu, X. L. Cao, Tao Luo, XiangYang Wen, Xue-Feng Lu, Bin Meng, S. Xiao, Y. B. Chen, Junqiang Zhang, Tong Li, H. W. Liu, N. Sai, Mao-Shun Li, Yunchao Liu, Sisi Yang, Y. J. Yang, S. M. Jia, Yuan You, L. D. Kong, Songbo Zhang, Cunguo Wang, Qi-Bin Yi, Yu-Dong Gu, Q. Q. Yin, Y. P. Chen, Xuelong Li, J. Guan, X. J. Liu, W. Z. Zhang, Yuan-Yuan Du, Gang Chen, X. H. Liang, G. C. Xiao, R. L. Zhuang, GuoQing Liu, Jia Huo, Y. Nang, Gang Li, Shaolin Xiong, Y. J. Zhang, H. Gao, Qiu-Yi Luo, Z. Zhang, Y. L. Tuo, J. W. Yang, Bing Zhang, B. Y. Wu, Lian Tao, X. Y. Song, H. S. Zhao, G. F. Wang, W. S. Wang, Ge Ou, W. C. Zhang, J. Y. Nie, Yi-Qiao Dong, Cheng-Cheng Guo, C. K. Li, H. Xu, Z. W. Li, Da-Wei Han, Z. L. Zhang, M. X. Fu, Yue Zhang, Ya Fang Huang, J. Z. Wang, L. Chen, Wan-Chang Zhang, Weiguang Cui, Qingcui Bu, Min Gao, and J. L. Qu

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010504 meteorology & atmospheric sciences, X-ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Magnetar, 01 natural sciences, Coincidence, Radio spectrum, 0103 physical sciences, Thermal, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Event (particle physics), 0105 earth and related environmental sciences, Delay time
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., 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
2021
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3. Deadtime calculation method of the High Energy X-ray telescope (HE) onboard the Insight-HXMT satellite

Author

Yupeng Xu, Shuang-Nan Zhang, Yu-Xuan Zhu, Y. F. Zhang, Xuelong Li, X. Y. Song, G. H. Gao, Qi-Bin Yi, Shaolin Xiong, C. Z. Liu, H. Gao, S. Xiao, F. J. Lu, Bo Li, L. M. Song, Xiong Li, Xue-Feng Lu, Tong Li, Z. Chang, C. K. Li, Z. W. Li, C. Cai, Wei Chen, and Ming-Yu Ge

Subjects
Physics, Data processing, Photon, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Detector, Astronomy and Astrophysics, X-ray telescope, 01 natural sciences, law.invention, Computational physics, Telescope, Space and Planetary Science, law, 0103 physical sciences, Satellite, Transient (oscillation), Nuclear Experiment, Gamma-ray burst, 010303 astronomy & astrophysics
Abstract

Deadtime is the time period during which a detector processes the previous photon event and any later events will be ignored, thus the calculation of deadtime is of great importance to reconstruct the incident photon flux from the recorded counts. The High Energy X-ray telescope (HE) on-board the Insight-HXMT satellite records the deadtime only for a fixed time bin (i.e. 1 s), therefore it is impossible to directly obtain the deadtime for an arbitrary time interval, especially for high-energy transients much shorter than one second. Based on the electronics model of HE, we establish a deadtime calculation method to derive the deadtime in any time interval. We apply this method to transient sources observed by HE, including Gamma-ray Bursts (GRB) and Terrestrial Gamma-ray Flashes (TGF). Furthermore, since the data processing capacity of HE electronics is limited, HE suffers data saturation for very bright GRBs. During the saturation period, a significant part of counts signal cannot be recorded. We find that the amount of lost counts can be estimated by comparing the recorded 1 s deadtime and the calculated deadtime using the method mentioned above.

Published
2020
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4. Joint analysis of energy and RMS spectra from MAXI J1535-571 with Insight-HXMT

Author

Z. W. Li, Jin-Lu Qu, He Gao, Y. C. Zhu, Xin Lu, J. X. Wang, ShaoZhen Liu, S. Yang, Xufang Li, Z. Zhang, Z. L. Zhang, Gang Li, W. C. Zhang, Yan Zhu, Long Ji, N. Sai, F. Zhang, Wenda Zhang, Bin Meng, Y. Tan, W. C. Jiang, Chuan-Peng Zhang, He-Yang Liu, Guo-Ming Chen, ShiJie Zheng, Bobing Wu, Y. G. Zheng, C. Cai, J. F. Zhou, D. K. Zhou, T. Luo, Ti-Pei Li, Shuo Xiao, Yuan-Yuan Du, Zhe Chang, Y. N. Liu, X.W. Ma, Tianran Chen, Shu-Mei Jia, Yu-Dong Gu, Bo Lu, Mingyu Wu, Lian Tao, Bing Li, Xuchao Zhao, Jing Jin, Jia Huo, X. Y. Wen, Ju Guan, Fangjun Lu, Jundan Nie, Ge Ou, X. F. Li, Cheng-Cheng Guo, M. Gao, Lei Sun, Hongwei Liu, Y. G. Li, C. Z. Liu, Luhua Jiang, H. M. Zhang, C. Wang, W. S. Wang, W. Z. Zhang, W. G. Li, He Xu, G. H. Gao, Jin-Yuan Liao, X. L. Cao, Min-Xue Fu, Shaolin Xiong, Y. Nang, Y. S. Wang, Junqiang Zhang, Mingzhe Li, Jinyi Yang, Y. Zhang, C. K. Li, Y. Huang, GuoQing Liu, P. J. Wang, Youcai Zhang, Jing-Kang Deng, Xiaohua Liang, G. F. Wang, Yi Zhang, Yuan You, Youli Tuo, Xin Ren, Yin Xu, Weiguang Cui, Q. Luo, Qingcui Bu, L. D. Kong, Y. B. Chen, Ming-Yu Ge, Xiao-Jing Liu, Da-Wei Han, Shuang-Nan Zhang, Li-Ming Song, Wei-Wei Cui, Aimei Zhang, Shuinai Zhang, Peng Zhang, Y. W. Dong, G. C. Xiao, HongSheng Zhao, Y. P. Chen, Xiaobo Li, L. Chen, Yi-Yan Yang, X. Y. Song, Y. J. Yang, T. Zhang, Q. B. Yi, and B. Y. Wu

Subjects
Physics, 010308 nuclear & particles physics, Oscillation, Astrophysics::High Energy Astrophysical Phenomena, Binary number, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Spectral line, law.invention, Telescope, Black hole, Space and Planetary Science, law, 0103 physical sciences, Modulation (music), Satellite, 010303 astronomy & astrophysics, Energy (signal processing)
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
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5. Diagnostic of the spectral properties of Aquila X-1 by Insight-HXMT snapshots during the early propeller phase

Author

Jing-Kang Deng, Shaolin Xiong, Q. Luo, Xiaohua Liang, Yuan You, Youli Tuo, Jing Jin, Yin Xu, Jinyi Yang, X. F. Li, Z. L. Zhang, Ju Guan, Y. B. Chen, Lei Sun, Fangjun Lu, Da-Wei Han, Mingzhe Li, W. G. Li, Wenda Zhang, C. Cai, Chuan-Peng Zhang, Y. Huang, Z. W. Li, Jundan Nie, Can Güngör, Hongwei Liu, Li-Ming Song, Y. G. Li, Bobing Wu, Andrea Santangelo, Xufang Li, ShiJie Zheng, Min-Xue Fu, Luhua Jiang, Ti-Pei Li, Gang Li, Y. W. Dong, N. Sai, J. X. Wang, Y. Nang, G. C. Xiao, Shuinai Zhang, Jing Zhou, Xin Lu, Y. N. Liu, Yuan-Yuan Du, Jia Huo, X. Y. Wen, Junqiang Zhang, Y. Tan, F. Zhang, Bin Meng, W. C. Jiang, G. F. Wang, Yi Zhang, C. K. Li, Wei-Wei Cui, L. D. Kong, H. M. Zhang, Shuo Xiao, W. C. Zhang, M. Gao, Bo Lu, Guo-Ming Chen, Xuchao Zhao, C. Wang, Shu-Mei Jia, Shuang-Nan Zhang, G. H. Gao, Aimei Zhang, Ge Ou, Weiguang Cui, Qingcui Bu, HongSheng Zhao, C. Z. Liu, W. Z. Zhang, Y. Zhang, Mingyu Wu, Q. Q. Yin, Y. P. Chen, GuoQing Liu, Bing Li, Y. J. Yang, D. K. Zhou, Y. S. Wang, Yi Chen, Ming-Yu Ge, Xiao-Jing Liu, Xiaobo Li, Youcai Zhang, S. Yang, L. Chen, X. Y. Song, Zhe Chang, T. Zhang, X.W. Ma, Lian Tao, Yi-Nan Zhu, Cheng-Cheng Guo, W. S. Wang, T. Luo, Q. B. Yi, B. Y. Wu, Jin-Yuan Liao, X. L. Cao, He Gao, Z. Zhang, Yan Zhu, Long Ji, Tianran Chen, and Yu-Dong Gu

Subjects
Physics, Accretion (meteorology), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, Spectral properties, Propeller, Phase (waves), Astronomy and Astrophysics, Astrophysics, 01 natural sciences, law.invention, Telescope, Accretion disc, Space and Planetary Science, Sky, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Spectral analysis, 010303 astronomy & astrophysics, media_common
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.

Published
2020
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6. Insight-HXMT study of the timing properties of Sco X-1

Author

J. Z. Wang, J. Y. Nie, Y. J. Yang, Xiaobo Li, Weiguang Cui, J. Guan, Qingcui Bu, L. M. Song, Yu-Dong Gu, G. C. Xiao, Luhua Jiang, J. Jin, D. K. Zhou, Y. X. Zhu, X. H. Liang, W. C. Zhang, B. Lu, GuoQing Liu, Ming-Yu Ge, Chun-sheng Zhang, Yi-Qiao Dong, Min Gao, B. B. Wu, Wenhan Jiang, Jia Huo, Y. H. Tan, Cheng-Cheng Guo, J. L. Qu, Gang Li, Y. B. Chen, F. J. Lu, Xin-Fu Zhao, R. C. Shang, J. F. Zhou, Bing Li, XiangYang Wen, Lian Tao, Y. S. Wang, Gang Chen, Wei Cui, B. Y. Wu, Tian-Xiang Chen, T. Zhang, X. Y. Song, X. J. Liu, Tao Luo, Da-Wei Han, Bin Meng, L. Chen, Mao-Shun Li, S. Xiao, Xue-Feng Lu, Tong Li, S. M. Jia, Fuqin Zhang, Z. Zhang, S. N. Zhang, Z. Chang, Yunchao Liu, R. L. Zhuang, Junqiang Zhang, Wan-Chang Zhang, W. S. Wang, Y. Nang, Ge Ou, Yuan-Yuan Du, W. Z. Zhang, Lei Sun, Y. J. Jin, C. Z. Liu, J. K. Deng, L. D. Kong, H. W. Liu, N. Sai, Shaolin Xiong, Cunguo Wang, Y. J. Zhang, X. H. Ma, H. Gao, Sisi Yang, Yupeng Xu, Qiu-Yi Luo, X. F. Li, H. S. Zhao, G. F. Wang, Y. L. Tuo, C. Cai, Wenxiong Li, J. W. Yang, Yu-Xuan Zhu, X. L. Cao, X. X. Li, S. J. Zheng, Yuan You, G. H. Gao, Qi-Bin Yi, M. Wu, Q. Q. Yin, Y. P. Chen, Y. Zhang, Y. G. Li, Aimei Zhang, J. Y. Liao, H. M. Zhang, Y. F. Zhang, Ya Fang Huang, Z. L. Zhang, C. K. Li, Z. W. Li, and M. X. Fu

Subjects
Physics, High energy, 010308 nuclear & particles physics, Phase (waves), Astronomy and Astrophysics, Astrophysics, Horizontal branch, 01 natural sciences, law.invention, Telescope, Root mean square, Space and Planetary Science, law, 0103 physical sciences, Modulation (music), 010303 astronomy & astrophysics, Energy (signal processing), Flare
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 ( I n s i g h t -HXMT) from July 2017 to August 2018. A complete Z-track hardness-intensity diagram (HID) is obtained. The normal branch oscillations (NBOs) at ∼ 6 Hz in the lower part of the normal branch (NB) and the flare branch oscillations (FBOs) at ∼ 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 I n s i g h t -HXMT, while the horizontal branch oscillations (HBOs) at ∼ 40 Hz and the kilohertz quasi-periodic oscillations (kHz QPOs) at ∼ 800 Hz are found simultaneously above 20 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 ∼ 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
2020
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7. Insight-HXMT observation on 4U 1608–52: Evolving spectral properties of a bright type-I X-ray burst

Author

S. N. Zhang, W. C. Jiang, W. S. Wang, Ge Ou, Z. Chang, J. F. Zhou, X.Q. Ren, C. Z. Liu, C. L. Zhang, Tian-Xiang Chen, Min Gao, H. S. Zhao, Sisi Yang, G. F. Wang, D. K. Zhou, Yi Zhang, X. J. Liu, J. L. Qu, G. C. Xiao, Jia Huo, Z. L. Zhang, Y. G. Li, M. X. Fu, Ya Fang Huang, Bing Li, F. Zhang, Chun-sheng Zhang, X. F. Li, Aimei Zhang, W. Z. Zhang, J. Z. Wang, Liang Sun, Y. B. Chen, Xue-Feng Lu, F. J. Lu, S. M. Jia, XiangYang Wen, Lian Tao, Yuan You, Junke Zhang, Gang Li, Y. S. Wang, Wei Zhang, B. Y. Wu, Qi-Bin Yi, B. B. Wu, Mao-Shun Li, Yunchao Liu, Y. J. Yang, Tao Luo, Xiaobo Li, L. D. Kong, S. Xiao, Yi-Qiao Dong, X. L. Cao, W. C. Zhang, Q. Luo, Weiguang Cui, X. X. Li, Yuan-Yuan Du, J. Y. Liao, H. M. Zhang, Gang Chen, Qingcui Bu, B. Lu, Y. H. Tan, J. K. Deng, Cheng-Cheng Guo, H. W. Liu, N. Sai, Q. Q. Yin, Y. P. Chen, Y. F. Zhang, C. K. Li, L. M. Song, Yu-Dong Gu, J. Jin, G. H. Gao, Xin-Fu Zhao, S. J. Zheng, Y. X. Zhu, C. Cai, Z. W. Li, Zhi-Xiang Zhang, X. H. Ma, Ming-Yu Ge, M. Wu, Y. Zhang, C. Wang, Wenxiong Li, Andrea Santangelo, Yu-Xuan Zhu, Shaolin Xiong, Luhua Jiang, Y. P. Xu, Y. J. Zhang, H. Gao, X. H. Liang, J. Guan, Ti-Pei Li, Y. L. Tuo, J. W. Yang, GuoQing Liu, Wei Cui, Long Ji, T. Zhang, L. Chen, J. Y. Nie, Da-Wei Han, Bin Meng, and Y. Nang

Subjects
Physics, Thermonuclear fusion, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Spectral properties, X-ray, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Radius, Astrophysics, 01 natural sciences, symbols.namesake, Neutron star, Space and Planetary Science, 0103 physical sciences, Eddington luminosity, Reflection (physics), symbols, Spectral analysis, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

The evidences for the influence of thermonuclear (type-I) X-ray bursts upon the surrounding environments in neutron star low-mass X-ray binaries (LMXB) were detected previously via spectral and timing analyses. Benefitting from a broad energy coverage of Insight-HXMT, we analyze one photospheric radius expansion (PRE) burst, and find an emission excess at soft X-rays. Our spectral analysis shows that, such an excess is not likely relevant to the disk reflection induced by the burst emission and can be attributed to an enhanced pre-burst/persistent emission. We find that the burst and enhanced persistent emissions sum up to exceed Eddington luminosity by ∼ 40 percentages. We speculate that the enhanced emission is from a region beyond the PRE radius, or through the Comptonization of the corona.

Published
2019
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8. QPOs and Orbital elements of X-ray binary 4U 0115+63 during the 2017 outburst observed by Insight-HXMT

Author

Q Lou, Yuan You, Qi-Bin Yi, X. X. Li, S. J. Zheng, Cunguo Wang, J. Jin, H M Zhang, Xin-Fu Zhao, H. S. Zhao, Lei Sun, Wenhan Jiang, G. H. Gao, He-Yang Liu, Y. J. Yang, Xiong Li, Yu-Dong Gu, B. S. Liu, X. H. Ma, Y. P. Xu, Yi Zhang, Y. H. Tan, H. W. Liu, Y Z Ding, N. Sai, M. Wu, G. C. Xiao, W. C. Zhang, Yuan-Yuan Du, Y. G. Zheng, Y. Nang, C. Cai, L. Chen, C. Z. Liu, P. J. Wang, F. J. Lu, J. L. Qu, Bin Meng, Xue-Feng Lu, XiangYang Wen, L. D. Kong, Xuelong Li, J. Guan, S. M. Jia, Wenxiong Li, P Zhang, Fuqin Zhang, S. N. Zhang, Tian-Xiang Chen, Sisi Yang, X. L. Cao, C. K. Li, Y. B. Chen, D. K. Zhou, Y. S. Wang, Libin Wang, J. Y. Liao, Q. Q. Yin, Y. P. Chen, Lian Tao, Ti-Pei Li, R. C. Ma, Y. F. Zhang, Qingcui Bu, Bo Li, B. B. Wu, X. Y. Song, Shuang-Nan Zhang, Junqiang Zhang, W. S. Wang, L. M. Song, Wei Cui, Z. W. Li, Ming-Yu Ge, Wei Wang, Tao Luo, S. Xiao, Xin Ren, Ya Fang Huang, X. J. Liu, Jia Huo, C Zhi, Gang Li, B. Y. Wu, Shaolin Xiong, H. Gao, X. H. Liang, Y. L. Tuo, R. J. Yang, Wei Zhang, Cheng-Cheng Guo, Da-Wei Han, and J. Y. Nie

Subjects
Physics, Orbital elements, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, X-ray binary, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Light curve, 01 natural sciences, Spectral line, Luminosity, Neutron star, Wavelet, Space and Planetary Science, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Energy (signal processing)
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., 14 pages, 9 figures, and 6 tables. This work has been submitted to MNRAS after the referee's report

Published
2021

9. A Variable Ionized Disk Wind in the Black Hole Candidate EXO 1846–031

Author

Junjie Mao, H. M. Zhang, Junqiang Zhang, ShiJie Zheng, C. K. Li, Thomas Dauser, Yuan-Yuan Du, C. Cai, R. C. Shang, Bing Li, Ming-Yu Ge, Xiao-Jing Liu, Y. J. Yang, Xufang Li, Gang Li, Shu-Mei Jia, Mariano Mendez, Ge Ou, Y. Nang, L. D. Kong, Yi Zhang, P. Maggi, N. Sai, Yin Xu, Long Ji, Yanan Wang, Bin Meng, Han Zhao, S. Yang, Q. B. Yi, B. Y. Wu, Lei Sun, Y. Huang, W. G. Li, Shaolin Xiong, Fangjun Lu, Li-Ming Song, C. Z. Liu, Jing Jin, Bobing Wu, Mingyu Wu, Xiaohua Liang, Javier A. García, X. F. Li, Yuan You, Y. S. Wang, Ti-Pei Li, Tianran Chen, Youli Tuo, Xiong Li, Yu-Dong Gu, Jin-Lu Qu, Y. Tan, W. C. Jiang, Zhe Chang, F. Zhang, X.W. Ma, Yuan Wang, Lian Tao, Diego Altamirano, L. Chen, X. Y. Song, D. K. Zhou, Wan-Chang Zhang, Jia Huo, X. Y. Wen, Z. W. Li, Xin Lu, G. C. Xiao, Jundan Nie, Hongwei Liu, Shuang-Nan Zhang, S. N. Zhang, Q. Q. Yin, Y. P. Chen, T. Luo, Liang Zhang, Wei Zhang, Cheng-Cheng Guo, W. S. Wang, Jin-Yuan Liao, X. L. Cao, G. H. Gao, Shuo Xiao, Xuchao Zhao, Ju Guan, Weiguang Cui, Qingcui Bu, Da-Wei Han, Q. Luo, Y. B. Chen, Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Astronomy

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010504 meteorology & atmospheric sciences, High-energy astronomy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Accretion (astrophysics), Spectral line, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Ionization, 0103 physical sciences, Reflection (physics), Intermediate state, Emission spectrum, Spectral resolution, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, QC, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
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
2021
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10. The Evolution of the Broadband Temporal Features Observed in the Black-hole Transient MAXI J1820+070 with Insight-HXMT

Author

Yanan Wang, Long Ji, S. N. Zhang, Mariano Méndez, J. L. Qu, Pierre Maggi, M. Y. Ge, Erlin Qiao, L. Tao, S. Zhang, Diego Altamirano, L. Zhang, X. Ma, F. J. Lu, T. P. Li, Y. Huang, S. J. Zheng, Y. P. Chen, Z. Chang, Y. L. Tuo, C. Güngör, L. M. Song, Y. P. Xu, X. L. Cao, Y. Chen, C. Z. Liu, Q. C. Bu, C. Cai, G. Chen, L. Chen, T. X. Chen, Y. B. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, Y. J. Jin, L. D. Kong, 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. Li, X. H. Liang, J. Y. Liao, G. Q. Liu, H. W. Liu, X. J. Liu, Y. N. Liu, B. Lu, X. F. Lu, Q. Luo, T. Luo, B. Meng, Y. Nang, J. Y. Nie, G. Ou, N. Sai, R. C. Shang, X. Y. Song, L. Sun, Y. Tan, G. F. Wang, J. Wang, W. S. Wang, Y. D. Wang, Y. S. Wang, X. Y. Wen, B. B. Wu, B. Y. Wu, M. Wu, G. C. Xiao, S. Xiao, S. L. Xiong, J. W. Yang, S. Yang, Y. J. Yang, Q. B. Yi, Q. Q. Yin, Y. You, 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. Zhao, X. F. Zhao, D. K. Zhou, J. F. Zhou, R. L. Zhuang, Y. X. Zhu, Y. Zhu, Lingjun Wang, Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Astronomy

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Range (particle radiation), Jet (fluid), Photon, 010504 meteorology & atmospheric sciences, Hardness ratio, Black holes, Astrophysics::High Energy Astrophysical Phenomena, Time lag, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Low-mass x-ray binary stars, Space and Planetary Science, 0103 physical sciences, Broadband, Transient (oscillation), Electronic band structure, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Compact objects, 0105 earth and related environmental sciences
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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11. Switches between accretion structures during flares in 4U 1901+03

Author

Z. Chang, Fuqin Zhang, S. N. Zhang, Qiu-Yi Luo, Y. B. Chen, B. B. Wu, Tao Luo, Aimei Zhang, J. Y. Zhang, Ming-Yu Ge, Armin Nabizadeh, Y. G. Li, S. Xiao, Y. L. Tuo, J. W. Yang, L. Chen, Chun-sheng Zhang, Peng Zhang, Yu-Dong Gu, Sergey S. Tsygankov, C. K. Li, Y. J. Jin, J. Y. Nie, M. X. Fu, Yue Zhang, X. J. Liu, Luhua Jiang, Y. P. Xu, Zhao Zhang, G. C. Xiao, Bo Li, H. Xu, Yu-Xuan Zhu, J. Z. Wang, X. H. Liang, W. Z. Zhang, L. Sun, Z. W. Li, G. H. Gao, Yanji Yang, Wan-Chang Zhang, Weiguang Cui, C. Cai, F. J. Lu, Yunchao Liu, Qingcui Bu, X. L. Cao, B. S. Liu, Bin Meng, D. K. Zhou, Y. J. Yang, Shaolin Xiong, Wenxiong Li, Tian-Xiang Chen, Lian Tao, Yi Zhang, Y. J. Zhang, M. Wu, Andrea Santangelo, XiangYang Wen, Suleimanov, H. Gao, Z. Zhang, L. D. Kong, X. Y. Song, Long Ji, W. C. Zhang, Q. B. Yi, B. Y. Wu, Mao-Shun Li, Q. Q. Yin, You-Hong Zhang, H. W. Liu, N. Sai, Da-Wei Han, J. Y. Liao, H. M. Zhang, Zhi Zhang, Ya Fang Huang, Y. F. Zhang, Min Gao, X. B. Li, B. Lu, J. L. Qu, Yi-Qiao Dong, Wenhan Jiang, Cheng-Cheng Guo, Y. S. Wang, Doroshenko, Yuan-Yuan Du, C. Z. Liu, Y X Zhu, Y. P. Chen, Sisi Yang, Y. H. Tan, J. F. Zhou, J. Jin, Xin-Fu Zhao, R. C. Shang, Xuelong Li, J. Guan, GuoQing Liu, Jia Huo, Gang Li, Lorenzo Ducci, Wei Cui, T. Zhang, Li-Ming Song, Xue-Feng Lu, Shuinai Zhang, S. M. Jia, He-Yang Liu, Y. Nang, R. L. Zhuang, J. K. Deng, C. Wang, X. H. Ma, H. S. Zhao, Ti-Pei Li, P. J. Wang, G. F. Wang, W. S. Wang, Ge Ou, Gang Chen, Yuan You, X. X. Li, and S. J. Zheng

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Accretion (astrophysics), Spectral line, Beam pattern, Neutron star, Accretion rate, Pulsar, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Polar cap, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
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., 11 pages, 8 figures, accepted for publication in MNRAS

Published
2020

12. A search for prompt gamma-ray counterparts to fast radio bursts in the Insight-HXMT data

Author

C. Guidorzi, M. Marongiu, R. Martone, L. Nicastro, S. L. Xiong, J. Y. Liao, G. Li, S. N. Zhang, L. Amati, F. Frontera, M. Orlandini, P. Rosati, E. Virgilli, S. Zhang, Q. C. Bu, C. Cai, X. L. Cao, Z. Chang, G. Chen, L. Chen, T. X. Chen, Y. B. Chen, Y. P. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, M. Y. Ge, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, Y. Huang, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, Y. J. Jin, L. D. Kong, 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. Li, X. H. Liang, B. S. Liu, C. Z. Liu, G. Q. Liu, H. W. Liu, X. J. Liu, Y. N. Liu, B. Lu, F. J. Lu, X. F. Lu, Q. Luo, T. Luo, R. C. Ma, X. Ma, B. Meng, Y. Nang, J. Y. Nie, G. Ou, J. L. Qu, N. Sai, R. C. Shang, L. M. Song, X. Y. Song, L. Sun, Y. Tan, L. Tao, Y. L. Tuo, C. Wang, G. F. Wang, J. Wang, W. S. Wang, Y. S. Wang, X. Y. Wen, B. Y. Wu, B. B. Wu, M. Wu, G. C. Xiao, S. Xiao, Y. P. Xu, J. W. Yang, S. Yang, Y. J. Yang, Q. B. Yi, Q. Q. Yin, Y. You, 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. Zhang, S. J. Zheng, D. K. Zhou, J. F. Zhou, Y. X. Zhu, Y. Zhu, and R. L. Zhuang

Subjects
radiation mechanism: non-thermal, Astrophysics::High Energy Astrophysical Phenomena, Continuum (design consultancy), Socio-culturale, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Magnetar, 01 natural sciences, Luminosity, law.invention, Telescope, fast radio burst, radiation mechanism: non-thermal, law, 0103 physical sciences, fast radio burst, 010306 general physics, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Gamma ray, Astronomy and Astrophysics, Stars, Neutron star, Space and Planetary Science, 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}, Comment: 15 pages, 3 figures, 6 tables, accepted by A&A

Published
2020
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13. Insight-HXMT firm detection of the highest energy fundamental cyclotron resonance scattering feature in the spectrum of GRO J1008-57

Author

M. Y. Ge, L. Ji, S. N. Zhang, A. Santangelo, C. Z. Liu, V. Doroshenko, R. Staubert, J. L. Qu, S. Zhang, F. J. Lu, L. M. Song, T. P. Li, L. Tao, Y. P. Xu, X. L. Cao, Y. Chen, Q. C. Bu, C. Cai, Z. Chang, G. Chen, L. Chen, T. X. Chen, Y. B. Chen, Y. P. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, Y. Huang, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, Y. J. Jin, L. D. Kong, 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. Li, X. H. Liang, J. Y. Liao, B. S. Liu, G. Q. Liu, H. W. Liu, X. J. Liu, Y. N. Liu, B. Lu, X. F. Lu, Q. Luo, T. Luo, X. Ma, B. Meng, Y. Nang, J. Y. Nie, G. Ou, N. Sai, R. C. Shang, X. Y. Song, L. Sun, Y. Tan, Y. L. Tuo, C. Wang, G. F. Wang, J. Wang, L. J. Wang, W. S. Wang, Y. D. Wang, Y. S. Wang, X. Y. Wen, B. B. Wu, B. Y. Wu, M. Wu, G. C. Xiao, S. Xiao, S. L. Xiong, H. Xu, J. W. Yang, S. Yang, Y. J. Yang, Q. B. Yi, Q. Q. Yin, Y. You, 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. Zhao, X. F. Zhao, S. J. Zheng, Y. G. Zheng, D. K. Zhou, J. F. Zhou, R. L. Zhuang, Y. X. Zhu, and Y. Zhu

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010504 meteorology & atmospheric sciences, Scattering, Astrophysics::High Energy Astrophysical Phenomena, Cyclotron resonance, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Inelastic scattering, 01 natural sciences, Resonance (particle physics), Spectral line, Pulsar, Space and Planetary Science, 0103 physical sciences, Continuum (set theory), Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Line (formation)
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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14. Constraining the transient high-energy activity of FRB180916.J0158+65 with Insight-HXMT followup observations

Author

L. Chen, Yu-Dong Gu, Ya Fang Huang, R. J. Yang, Y. J. Yang, L. Wang, Junqiang Zhang, Wenhan Jiang, Qiu-Yi Luo, X. H. Liang, C. Z. Liu, G. C. Xiao, B. Y. Wu, Y. L. Tuo, Sisi Yang, He-Yang Liu, Wei Cui, W. S. Wang, Xiaobo Li, Wei Zhang, G. H. Gao, Ge Ou, Bing Li, B. B. Wu, Bin Meng, C. Guidorzi, F. Frontera, Yi Zhang, C. Cai, Luciano Nicastro, Lei Sun, Mauro Orlandini, M. Wu, J. Jin, Xin-Fu Zhao, H. S. Zhao, Y. Nang, Cheng-Cheng Guo, Y. P. Xu, Tao Luo, Yuan You, Qingcui Bu, S. Xiao, C. K. Li, Qi-Bin Yi, Shaolin Xiong, P. J. Wang, Wenxiong Li, Y. B. Chen, J. Y. Liao, H. M. Zhang, L. D. Kong, B. S. Liu, X. X. Li, H. Gao, H. W. Liu, N. Sai, Z. W. Li, W. C. Zhang, R. C. Ma, Min Gao, Fuqin Zhang, Y. F. Zhang, S. N. Zhang, D. K. Zhou, C. Wang, J. L. Qu, J. Guan, Lorenzo Amati, Y. G. Zheng, Y. S. Wang, Xin Ren, Tian-Xiang Chen, E. Virgilli, Lian Tao, Z. Chang, Da-Wei Han, Jia Huo, Y. H. Tan, X. Y. Song, X. F. Li, Gang Li, P. Zhang, Ming-Yu Ge, J. Y. Nie, Yuan-Yuan Du, F. J. Lu, XiangYang Wen, X. H. Ma, Li-Ming Song, Xue-Feng Lu, Tong Li, S. M. Jia, X. J. Liu, X. L. Cao, Q. Q. Yin, Y. P. Chen, S. J. Zheng, ITA, and CHN

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Socio-culturale, Context (language use), Astrophysics, Magnetar, 01 natural sciences, law.invention, Telescope, stars: magnetars, law, 0103 physical sciences, 010306 general physics, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Fast radio burst, Detector, Astronomy and Astrophysics, radiation mechanisms: non-thermal, stars: magnetars, radiation mechanisms: non-thermal, Wavelength, Space and Planetary Science, Phase space, Astrophysics - High Energy Astrophysical Phenomena, Energy (signal processing)
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 pages, 3 figures, accepted by A&A

Published
2020

15. X-ray reprocessing in accreting pulsar GX 301-2 observed with Insight-HXMT

Author

G. H. Gao, X. X. Li, M. Wu, S. J. Zheng, Y. G. Zheng, Y. Nang, Mauro Orlandini, J. Y. Liao, H. M. Zhang, Y. L. Tuo, Y. J. Yang, R. C. Ma, Y. F. Zhang, X. B. Li, B. S. Liu, Yuan You, X. Q. Ren, Yanji Yang, Armin Nabizadeh, C. Cai, L. Chen, Tian-Xiang Chen, Wenxiong Li, Wan-Chang Zhang, W. S. Wang, Yi Zhang, Ge Ou, Andrea Santangelo, R. J. Yang, Bo Li, Peng Zhang, Qiu-Yi Luo, B. B. Wu, Cunguo Wang, H. S. Zhao, Li-Ming Song, Ming-Yu Ge, C. K. Li, F. J. Lu, Xue-Feng Lu, Y. P. Chen, Shuinai Zhang, Tong Li, Y. H. Tan, P. J. Wang, J. Y. Zhang, Victor Doroshenko, Shaolin Xiong, S. M. Jia, XiangYang Wen, Ling-Jun Wang, H. Gao, Jiren Liu, X. H. Ma, Z. W. Li, Yuan-Yuan Du, C. Z. Liu, D. K. Zhou, Sisi Yang, Ya Fang Huang, J. Jin, Xin-Fu Zhao, G. Li, Tao Luo, S. Xiao, Yu-Dong Gu, X. J. Liu, D. Gavran, X. L. Cao, Q. Q. Yin, Q. B. Yi, B. Y. Wu, V. F. Suleimanov, L. D. Kong, Y. B. Chen, X. H. Liang, L. Sun, Fuqin Zhang, S. N. Zhang, Long Ji, Z. Chang, Y. H. Zhang, Y. P. Xu, Wenhan Jiang, H. W. Liu, N. Sai, Y. S. Wang, W. C. Zhang, Xuelong Li, J. Guan, Lian Tao, Cheng-Cheng Guo, X. Y. Song, Jia Huo, Lorenzo Ducci, J. Y. Nie, Bin Meng, Wei Cui, G. C. Xiao, Qingcui Bu, Da-Wei Han, J. L. Qu, Hongfei Liu, ITA, DEU, and CHN

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Accretion (meteorology), Astrophysics::High Energy Astrophysical Phenomena, X-ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Radiation, 01 natural sciences, Neutron star, Pulsar, Space and Planetary Science, Ionization, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010306 general physics, Absorption (electromagnetic radiation), Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Equivalent width, Astrophysics::Galaxy Astrophysics
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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16. Discovery of delayed spin-up behavior following two large glitches in the Crab pulsar, and the statistics of such processes

Author

M. Y. Ge, S. N. Zhang, F. J. Lu, T. P. Li, J. P. Yuan, X. P. Zheng, Y. Huang, S. J. Zheng, Y. P. Chen, Z. Chang, Y. L. Tuo, Q. Cheng, C. Güngör, L. M. Song, Y. P. Xu, X. L. Cao, Y. Chen, C. Z. Liu, S. Zhang, J. L. Qu, Q. C. Bu, C. Cai, G. Chen, L. Chen, M. Z. Chen, T. X. Chen, Y. B. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, L. F. Hao, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, C. J. Jin, J. Jin, Y. J. Jin, L. D. Kong, 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. Li, Z. Y. Liu, X. H. Liang, J. Y. Liao, G. Q. Liu, H. W. Liu, X. J. Liu, Y. N. Liu, B. Lu, X. F. Lu, Q. Luo, T. Luo, X. Ma, B. Meng, Y. Nang, J. Y. Nie, G. Ou, N. Sai, R. C. Shang, X. Y. Song, L. Sun, Y. Tan, L. Tao, C. Wang, G. F. Wang, J. Wang, J. B. Wang, M. Wang, N. Wang, W. S. Wang, Y. D. Wang, Y. S. Wang, X. Y. Wen, Z. G. Wen, B. B. Wu, B. Y. Wu, M. Wu, G. C. Xiao, S. Xiao, S. L. Xiong, Y. H. Xu, W. M. Yan, J. W. Yang, S. Yang, Y. J. Yang, Q. B. Yi, Q. Q. Yin, Y. You, Y. L. Yue, 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. Zhang, H. S. Zhao, X. F. Zhao, W. Zheng, D. K. Zhou, J. F. Zhou, X. Zhou, R. L. Zhuang, Y. X. Zhu, and Y. Zhu

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010504 meteorology & atmospheric sciences, Crab Pulsar, Astrophysics::High Energy Astrophysical Phenomena, Total frequency, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Glitch, Stars, Crab Nebula, Amplitude, Pulsar, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Spin-up, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
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 $, Comment: 25 pages, 8 figures

Published
2020
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17. Hot disk of the Swift J0243.6+6124 revealed by Insight-HXMT

Author

J. K. Deng, X. H. Ma, B. B. Wu, Min Gao, Lian Tao, L. Chen, Yi-Yan Yang, X. Y. Song, C. L. Zhang, Xue-Feng Lu, Shuinai Zhang, H. S. Zhao, S. M. Jia, C. Z. Liu, M. X. Fu, Y. Nang, Ya Fang Huang, Tao Luo, Wan-Chang Zhang, Bin Meng, Mao-Shun Li, Sisi Yang, X. X. Li, L. J. Qu, J. Z. Wang, Y. L. Tuo, G. F. Wang, J. W. Yang, W. C. Jiang, Tian-Xiang Chen, Weiguang Cui, Qingcui Bu, Yunchao Liu, Y. J. Jin, L. M. Song, Sergey S. Tsygankov, Y. J. Yang, V. Doroshenko, Ti-Pei Li, F. Zhang, Yuan-Yuan Du, S. J. Zheng, Gang Chen, W. S. Wang, J. Y. Liao, H. M. Zhang, Junke Zhang, Wenxiong Li, Qing-He Zhang, Ge Ou, Da-Wei Han, XiangYang Wen, J. Y. Nie, Y. F. Zhang, Andrea Santangelo, Shaolin Xiong, Bo Lu, J. Jin, Y. J. Zhang, Xuchao Zhao, H. Gao, W. Z. Zhang, Wei Zhang, G. H. Gao, Yi-Qiao Dong, Y. H. Tan, Cheng-Cheng Guo, M. Wu, Y. Zhang, Fangjun Lu, Y. B. Chen, Alexander A. Mushtukov, Z. Zhang, Long Ji, Y. P. Chen, Bing Li, Y. S. Wang, T. Zhang, Chun-sheng Zhang, Xiaobo Li, W. Hu, X. F. Li, X. H. Liang, C. L. Zou, Z. L. Zhang, C. K. Li, G. C. Xiao, H. Xu, Y. X. Zhu, Z. W. Li, Ming-Yu Ge, Z. J. Li, ShaoZhen Liu, L. D. Kong, Yidong Xu, Yu-Dong Gu, S. N. Zhang, Jia Huo, Gang Li, X. L. Cao, J. Zhao, J. Guan, Aimei Zhang, GuoQing Liu, Wei Cui, Yu-Xuan Zhu, X. J. Liu, Liang Sun, Y. G. Li, Luhua Jiang, Z. Chang, Yujuan Liu, H. W. Liu, and N. Sai

Subjects
Swift, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Magnetosphere, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Pulsar, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, computer.programming_language, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Scattering, Spectral properties, Astronomy and Astrophysics, Accretion (astrophysics), Neutron star, Radiation pressure, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, computer
Abstract

We report on analysis of observations of the bright transient X-ray pulsar \src obtained during its 2017-2018 giant outburst with Insight-HXMT, \emph{NuSTAR}, and \textit{Swift} observatories. We focus on the discovery of a sharp state transition of the timing and spectral properties of the source at super-Eddington accretion rates, which we associate with the transition of the accretion disk to a radiation pressure dominated (RPD) state, the first ever directly observed for magnetized neutron star. This transition occurs at slightly higher luminosity compared to already reported transition of the source from sub- to super-critical accretion regime associate with onset of an accretion column. We argue that this scenario can only be realized for comparatively weakly magnetized neutron star, not dissimilar to other ultra-luminous X-ray pulsars (ULPs), which accrete at similar rates. Further evidence for this conclusion is provided by the non-detection of the transition to the propeller state in quiescence which strongly implies compact magnetosphere and thus rules out magnetar-like fields., Submitted to MNRAS

Published
2019
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18. Timing analysis of 2S 1417-624 observed with NICER and Insight-HXMT

Author

Tao Luo, J. Y. Zhang, B. B. Wu, G. H. Gao, Z. L. Zhang, Gang Chen, M. Wu, Y. Zhang, C. K. Li, Wei Zhang, Y. P. Chen, Y. H. Tan, Yi-Qiao Dong, H. Xu, Y. J. Jin, Victor Doroshenko, Shaolin Xiong, Z. W. Li, Cheng-Cheng Guo, F. J. Lu, Ya Fang Huang, Bo Li, Y. J. Zhang, J. Jin, J. K. Deng, H. Gao, L. Chen, Yi-Yan Yang, J. Y. Liao, H. M. Zhang, Tian-Xiang Chen, Yunchao Liu, XiangYang Wen, X. X. Li, Y. F. Zhang, X. B. Li, X. H. Ma, Can Güngör, Li-Ming Song, Xue-Feng Lu, Suo Liu, Xuchao Zhao, W. C. Zhang, Y. S. Wang, J. Zhao, Y. Nang, J. Y. Nie, S. J. Zheng, Mao-Shun Li, Lian Tao, X. H. Liang, L. Sun, Y. G. Li, Qing-He Zhang, Y. L. Tuo, Aimei Zhang, J. W. Yang, C. Z. Liu, S. M. Jia, X. Y. Song, Y. B. Chen, Luhua Jiang, W. Hu, L. J. Qu, H. W. Liu, Sisi Yang, Yu-Xuan Zhu, Z. Zhang, Long Ji, N. Sai, Yuan-Yuan Du, Chun-sheng Zhang, Wenhan Jiang, C. L. Zou, Yupeng Xu, X. J. Liu, X. L. Cao, Z. Chang, C. L. Zhang, Yujuan Liu, Wenxiong Li, B. Lu, S. N. Zhang, Andrea Santangelo, Y. X. Zhu, Ming-Yu Ge, Jia Huo, Gang Li, Lorenzo Ducci, Wei Cui, T. Zhang, W. Z. Zhang, Ti-Pei Li, Xuelong Li, J. Guan, Z. J. Li, L. D. Kong, GuoQing Liu, Bin Meng, Yu-Dong Gu, Y. J. Yang, G. C. Xiao, Fuqin Zhang, W. S. Wang, Ge Ou, Da-Wei Han, Min Gao, H. S. Zhao, M. X. Fu, J. Z. Wang, Weiguang Cui, G. F. Wang, and Qingcui Bu

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Accretion (meteorology), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Theoretical models, FOS: Physical sciences, Static timing analysis, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Radiation, 01 natural sciences, Luminosity, Magnetic field, QC Physics, Pulsar, Space and Planetary Science, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Fermi Gamma-ray Space Telescope
Abstract

We present a study of timing properties of the accreting pulsar 2S 1417-624 observed during its 2018 outburst, based on Swift/BAT, Fermi/GBM, Insight-HXMT and NICER observations. We report a dramatic change of the pulse profiles with luminosity. The morphology of the profile in the range 0.2-10.0keV switches from double to triple peaks at $\sim2.5$ $\rm \times 10^{37}{\it D}_{10}^2\ erg\ s^{-1}$ and from triple to quadruple peaks at $\sim7$ $\rm \times 10^{37}{\it D}_{10}^2\ erg\ s^{-1}$. The profile at high energies (25-100keV) shows significant evolutions as well. We explain this phenomenon according to existing theoretical models. We argue that the first change is related to the transition from the sub to the super-critical accretion regime, while the second to the transition of the accretion disc from the gas-dominated to the radiation pressure-dominated state. Considering the spin-up as well due to the accretion torque, this interpretation allows to estimate the magnetic field self-consistently at $\sim7\times 10^{12}$G., 7 pages, 4 figures, 1 tables, accepted for publication in MNRAS

Published
2019

19. Insight-HXMT Observations of a Possible Fast Transition from the Jet- to Wind-dominated State during a Huge Flare of GRS 1915+105

Author

R. J. Yang, Qiu-Yi Luo, L. Chen, H. S. Zhao, Y. L. Tuo, J. Y. Liao, H. M. Zhang, Y. Nang, Lei Sun, C. Z. Liu, Lian Tao, D. K. Zhou, R. C. Ma, Y. F. Zhang, Yuan You, Y. H. Zhang, X. Y. Song, X. H. Ma, Yuan-Yuan Du, Qi-Bin Yi, B. Y. Wu, P. J. Wang, Tao Luo, Bo Liu, B. B. Wu, Xuelong Li, J. Guan, Li-Ming Song, S. Xiao, Bo Li, Shaolin Xiong, X. X. Li, Xue-Feng Lu, H. Gao, G. H. Gao, Tong Li, S. M. Jia, Y. P. Xu, Sisi Yang, S. J. Zheng, F. J. Lu, M. Wu, Jia Huo, XiangYang Wen, Y. H. Tan, Ya Fang Huang, Peng Zhang, Qingcui Bu, Y. G. Zheng, H. W. Liu, Y. J. Yang, X. L. Cao, Gang Li, W. S. Wang, Tian-Xiang Chen, N. Sai, Cunguo Wang, C. K. Li, Ge Ou, W. C. Zhang, S. N. Zhang, Y. B. Chen, Junqiang Zhang, Q. Q. Yin, Z. W. Li, Y. P. Chen, G. C. Xiao, J. Jin, Xin-Fu Zhao, X. J. Liu, Y. S. Wang, Wenhan Jiang, Ling-Jun Wang, C. Cai, Wenxiong Li, Gang Chen, Z. Chang, Da-Wei Han, L. D. Kong, Xiong Li, Yu-Dong Gu, Bin Meng, Min Gao, Ming-Yu Ge, X. H. Liang, J. L. Qu, Hongfei Liu, Fuqin Zhang, Long Ji, X. Q. Ren, Wei Cui, J. Y. Nie, Wei Zhang, and Cheng-Cheng Guo

Subjects
010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, X-ray binary, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Spectral line, Luminosity, law.invention, Astrophysical jet, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Accretion (meteorology), Astronomy and Astrophysics, Radius, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, Energy (signal processing), Flare
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
2021
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20. Insight-HXMT observations of the New Black Hole Candidate MAXI J1535-571: timing analysis

Author

Wei Zhang, Yi-Qiao Dong, Cheng-Cheng Guo, X. L. Cao, Fu-Guo Xie, Xian Hou, Yupeng Xu, Jiancheng Wang, Xian Li, Jundan Nie, Y. G. Li, Yunchao Liu, Z. Chang, Yujuan Liu, C. L. Zou, Luhua Jiang, Y. J. Yang, W. C. Jiang, C. Z. Liu, Wei Cui, Mao-Shun Li, J. K. Deng, J. F. Zhou, Tianmeng Zhang, B. B. Wu, Jia Huo, X. H. Ma, Ju Guan, J. F. Ji, Xiaobo Li, ShaoZhen Liu, Tianran Chen, Shan-Shan Weng, Gang Chen, Yu-Dong Gu, Lian Tao, Y. X. Zhu, Li-Ming Song, Ming-Yu Ge, Xiao-Jing Liu, Bing Li, Guobao Zhang, Xue-Feng Lu, H. W. Liu, Shuinai Zhang, W. Z. Zhang, Yuan-Yuan Du, Z. L. Zhang, Y. S. Wang, Wenxiong Li, GuoQing Liu, Y. H. Tan, L. Chen, Wenfei Yu, Hsiang-Kuang Chang, S. N. Zhang, Chuan-Peng Zhang, Ya Fang Huang, Y. Nang, C. L. Zhang, Limei Yan, S. Yang, G. H. Gao, Wan-Chang Zhang, Y. P. Chen, Can Güngör, Y. B. Chen, Ti-Pei Li, M. Wu, Y. Zhang, G. F. Wang, Y. L. Tuo, J. Y. Liao, H. M. Zhang, J. W. Yang, Y. F. Zhang, Bo Lu, Xuchao Zhao, M. X. Fu, Jia Zhang, C. K. Li, H. Wang, Wei Hu, Z. Zhang, X. X. Li, Weiguang Cui, Qing-He Zhang, Zhuo Li, Qingcui Bu, Shu-Mei Jia, W. S. Wang, Shaolin Xiong, HongSheng Zhao, H. Xu, Ge Ou, Y. J. Zhang, Z. W. Li, Da-Wei Han, H. Gao, S. J. Zheng, Tao Luo, X. H. Liang, Min Gao, J. Zhao, J. L. Qu, Liang Sun, Albert K. H. Kong, Aimei Zhang, Gang Li, N. Sai, Yu-Xuan Zhu, Bin Meng, Fangjun Lu, Y. J. Jin, J. Jin, R. C. Shang, WenHui Tao, G. C. Xiao, F. Zhang, and XiangYang Wen

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Static timing analysis, Centroid, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Phase lag, law.invention, Black hole, Telescope, Amplitude, Space and Planetary Science, law, 0103 physical sciences, Modulation (music), Intermediate state, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics
Abstract

We present the X-ray timing results of the new black hole candidate (BHC) MAXI J1535-571 during its 2017 outburst from Hard X-ray Modulation Telescope (\emph{Insight}-HXMT) observations taken from 2017 September 6 to 23. Following the definitions given by \citet{Belloni2010}, we find that the source exhibits state transitions from Low/Hard state (LHS) to Hard Intermediate state (HIMS) and eventually to Soft Intermediate state (SIMS). Quasi-periodic oscillations (QPOs) are found in the intermediate states, which suggest different types of QPOs. With the large effective area of \emph{Insight}-HXMT at high energies, we are able to present the energy dependence of the QPO amplitude and centroid frequency up to 100 keV which is rarely explored by previous satellites. We also find that the phase lag at the type-C QPOs centroid frequency is negative (soft lags) and strongly correlated with the centroid frequency. By assuming a geometrical origin of type-C QPOs, the source is consistent with being a high inclination system., Comment: 12 pages, 11 figures, Sumbitted to ApJ

Published
2018
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21. In-orbit Demonstration of X-Ray Pulsar Navigation with the Insight-HXMT Satellite

Author

S. J. Zheng, S. N. Zhang, F. J. Lu, W. B. Wang, Y. Gao, T. P. Li, L. M. Song, M. Y. Ge, D. W. Han, Y. Chen, Y. P. Xu, X. L. Cao, C. Z. Liu, S. Zhang, J. L. Qu, Z. Chang, G. Chen, L. Chen, T. X. Chen, Y. B. Chen, Y. P. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, Y. D. Gu, J. Guan, C. Gungor, C. C. Guo, W. Hu, Y. Huang, J. Huo, J. F. Ji, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, Y. J. Jin, B. Li, C. K. Li, G. Li, M. S. Li, W. Li, X. Li, X. B. Li, X. F. Li, Y. G. Li, Z. J. Li, Z. W. Li, X. H. Liang, J. Y. Liao, G. Q. Liu, H. W. Liu, S. Z. Liu, X. J. Liu, Y. Liu, Y. N. Liu, B. Lu, X. F. Lu, T. Luo, X. Ma, B. Meng, Y. Nang, J. Y. Nie, G Ou, N. Sai, R. C. Shang, L. Sun, Y. Tan, L. Tao, W. Tao, Y. L. Tuo, G. F. Wang, J. Wang, W. S. Wang, Y. S. Wang, X. Y. Wen, B. B. Wu, M. Wu, G. C. Xiao, S. L. Xiong, H. Xu, L. L. Yan, J. W. Yang, S. Yang, Y. J. Yang, A. M. Zhang, C. L. Zhang, C. M. Zhang, F. Zhang, H. M. Zhang, J. Zhang, Q. Zhang, T. Zhang, W. Zhang, W. C. Zhang, W. Z. Zhang, Y. Zhang, Y. F. Zhang, Y. J. Zhang, Z. Zhang, Z. L. Zhang, H. S. Zhao, J. L. Zhao, X. F. Zhao, Y. Zhu, Y. X. Zhu, and C. L. Zou

Subjects
Physics, High energy, Crab Pulsar, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, 01 natural sciences, law.invention, Telescope, Pulsar, Space and Planetary Science, law, 0103 physical sciences, Satellite, Astrophysics::Earth and Planetary Astrophysics, Orbit (control theory), Astrophysics - Instrumentation and Methods for Astrophysics, 010306 general physics, Observation data, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, X-ray pulsar
Abstract

In this work, we report the in-orbit demonstration of X-ray pulsar navigation with Insight-Hard X-ray Modulation Telescope (Insight-HXMT), which was launched on Jun. 15th, 2017. The new pulsar navigation method 'Significance Enhancement of Pulse-profile with Orbit-dynamics' (SEPO) is adopted to determine the orbit with observations of only one pulsar. In this test, the Crab pulsar is chosen and observed by Insight-HXMT from Aug. 31th to Sept. 5th in 2017. Using the 5-day-long observation data, the orbit of Insight-HXMT is determined successfully with the three telescopes onboard - High Energy X-ray Telescope (HE), Medium Energy X-ray Telescope (ME) and Low Energy X-ray Telescope (LE) - respectively. Combining all the data, the position and velocity of the Insight-HXMT are pinpointed to within 10 km (3 sigma) and 10 m/s (3 sigma), respectively., Accepted by the Astrophysical Journal Supplement

Published
2019
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22. Insight-HXMT Observations of 4U 1636-536: Corona Cooling Revealed with Single Short Type-I X-Ray Burst

Author

Y. P. Chen, S. Zhang, J. L. Qu, S. N. Zhang, L. Ji, L. D. Kong, X. L. Cao, Z. Chang, G. Chen, L. Chen, T. X. Chen, Y. Chen, Y. B. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, M. Y. Ge, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, W. Hu, Y. Huang, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, Y. J. Jin, 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. J. Li, Z. W. Li, X. H. Liang, J. Y. Liao, C. Z. Liu, G. Q. Liu, H. W. Liu, S. Z. Liu, X. J. Liu, Y. Liu, Y. N. Liu, B. Lu, F. J. Lu, X. F. Lu, T. Luo, X. Ma, B. Meng, Y. Nang, J. Y. Nie, G. Ou, N. Sai, L. M. Song, L. Sun, Y. Tan, L. Tao, W. H. Tao, Y. L. Tuo, G. F. Wang, H. Y. Wang, J. Wang, W. S. Wang, Y. S. Wang, X. Y. Wen, B. B. Wu, M. Wu, G. C. Xiao, S. L. Xiong, H. Xu, Y. P. Xu, L. L. Yan, J. W. Yang, S. Yang, Y. J. Yang, A. M. Zhang, C. L. Zhang, C. M. Zhang, F. Zhang, H. M. Zhang, J. Zhang, Q. Zhang, T. Zhang, W. Zhang, W. C. Zhang, W. Z. Zhang, Y. Zhang, Y. F. Zhang, Y. J. Zhang, Z. Zhang, Z. L. Zhang, H. S. Zhao, J. L. Zhao, X. F. Zhao, S. J. Zheng, Y. Zhu, Y. X. Zhu, and C. L. Zou

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Broad bandwidth, Stacking, X-ray, FOS: Physical sciences, Astronomy and Astrophysics, Economic shortage, Astrophysics, 01 natural sciences, Corona, law.invention, Space and Planetary Science, law, 0103 physical sciences, Spectral fitting, Astrophysics - High Energy Astrophysical Phenomena, 010306 general physics, 010303 astronomy & astrophysics, Flare
Abstract

Corona cooling was detected previously from stacking a series of short type-I bursts occurred during the low/had state of atoll outburst. Type-I bursts are hence regarded as sharp probe to our better understanding on the basic property of the corona. The launch of the first Chinese X-ray satellite Insight-HXMT has large detection area at hard X-rays which provide almost unique chance to move further in this research field. We report the first detection of the corona cooling by Insight-HXMT from single short type-I burst showing up during {\bf flare} of 4U 1636-536. This type-I X-ray burst has a duration of $\sim$13 seconds and hard X-ray shortage is detected with significance 6.2~$\sigma$ in 40-70 keV. A cross-correlation analysis between the lightcurves of soft and hard X-ray band, shows that the corona shortage lag the burst emission by 1.6 $\pm$1.2~s. These results are consistent with those derived previously from stacking a large amount of bursts detected by RXTE/PCA within a series of {\bf flares} of 4U 1636-536. Moreover, the broad bandwidth of Insight-HXMT allows as well for the first time to infer the burst influence upon the continuum spectrum via performing the spectral fitting of the burst, which ends up with the finding that hard X-ray shortage appears at around 40 keV in the continuum spectrum. These results suggest that the evolution of the corona along with the outburst{\bf /flare} of NS XRB may be traced via looking into a series of embedded type-I bursts by using Insight-HXMT., Comment: published in 2018, ApJL,864, L30

Published
2018
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