Physical origin of the non-physical spin evolution of MAXI J1820 + 070

Guan, J.; Tao, Lian; Zhang, S N; Zhang, W; Zhang, S; Ma, Ruican; Ge, M. Y.; Song, Liming; Li, T P; Xu, YP; Chen, Y; Cao, X. L.; Liu, C Z; Zhang, L.; Wang, Y N; Chen, Y P; Bu, Q. C.; Cai, C.; Chang, Zhi; Chen, L; Chen, T X; Chen, Y B; Cui, Wei-Hua; Du, Yan-Qi; Gao, G. H.; Gu, Y. D.; Guo, Chengcheng; Han, Danxiang; Huang, Y.; Jia, Haiqiang; Jia, S. M.; Jiang, Weichun; 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, Hanwei; Liu, H X; Liu, X J; Lu, Xiao-Meng; Luo, Q.; Luo, T.; Ma, Xiang; Meng, Bin; Nang, Y.; Nie, J. Y.; Ou, G.; Ren, Xiaokang; Sai, N.; Song, X. Y.; Sun, Luming; Tan, Ying; Wang, Chunling; Wang, L. J.; Wang, P J; Wang, W S; Wang, Y S; Wen, Xiang-Yang; Wu, B. B.; Wu, Bai-Yang; Wu, Mei‐Hwan; Xiao, G. C.; Xiao, Shuo; Xiong, S. L.; Yang, Rong-Jia; Yang, S.; Yang, Yi-Jung; Yi, Q. B.; Yin, Q. Q.; You, Y.; Zhang, F; Zhang, H M; Zhang, J; Zhang, Peng; Zhang, W C; Zhang, Y F; Zhang, Y H; Zhao, H. S.; Zhao, Xiaofan; Zheng, S.; Zheng, Y. G.; Zhou, D. K.

doi:10.1093/mnras/stab945

Cited by 27 publications

(17 citation statements)

References 62 publications

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“…The dataset from both satellites are not affected by photon pile-up effects. Similar spectra analysis of Cyg X-1 (Zhao et al 2020) and MAXI J1820-070 (You et al 2021;Zhao et al 2021;Guan et al 2021) using HXMT have been reported. The paper is organized as follows: in Section 2, we describe the detail of observations and data reduction; the data analysis and results are presented in Section 3; Section 4 includes discussions and Section 5 includes conclusions.…”

Section: Introductionsupporting

confidence: 77%

Analysis of the reflection spectra of MAXI J1535-571 in the hard and intermediate states

Dong,

Liu,

Tuo

et al. 2022

Preprint

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We report results on the joint-fit of the NuSTAR and HXMT data for the black hole X-ray binary candidate MAXI J1535-571. The observations were obtained in 2017 when the source evolved through the hard, hard-intermediate and soft-intermediate states over the rising phase of the outburst. After subtracting continuum components, X-ray reflection signatures are clearly showed in those observations. By modeling the relativistic reflection in detail, we find that the inner radius 𝑅 in is relatively stable with 𝑅 in 1.55𝑅 g during the three states, which implies that the inner radius likely extends to the innermost stable circular orbit even in the bright hard state. When adopting 𝑅 in = 𝑅 ISCO , the spin parameter is constrained to be 0.985 +0.002 −0.004 at 90% confidence (statistical only). The best-fitting results reveal that the inclination of the inner accretion disc is ∼ 70 − 74 degrees, which notably conflicts with the apparent orientation of the ballistic jet ( 45 degrees). In addition, both the photon index and the electron temperature increase during the transition from hard to soft state. It seems that the corona evolves from dense low-temperature in the LHS to tenuous high-temperature after the state transition, which indicates that the state transition is accompanied by the evolution of the coronal properties.

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Section: Introductionsupporting

confidence: 77%

Analysis of the reflection spectra of MAXI J1535-571 in the hard and intermediate states

Dong,

Liu,

Tuo

et al. 2022

Preprint

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“…MAXI J1820+070 is likely to harbor a slowly spinning black hole. Guan et al (2021) constrained the spin of the black hole to be a 0.2 0.3…”

Section: Introductionmentioning

confidence: 99%

The Accretion Flow Geometry of MAXI J1820+070 through Broadband Noise Research with Insight Hard X-ray Modulation Telescope

Yang

Zhang

Bu³

et al. 2022

ApJ

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Here we present a detailed study of the broadband noise in the power density spectra of the black hole X-ray binary MAXI J1820+070 during the hard state of its 2018 outburst, using Hard X-ray Modulation Telescope observations. The broadband noise shows two main humps, which might separately correspond to variability from a variable disk and two Comptonization regions. We fitted the two humps with multiple Lorentzian functions and studied the energy-dependent properties of each component up to 90–150 keV and their evolution with spectral changes. The lowest-frequency component is considered as the subharmonic of the quasiperiodic oscillation component and shows a different energy dependence compared with other broadband noise components. We found that although the fractional rms of all the broadband noise components mainly decreases with the energy, their rms spectra are different in shape. Above ∼20–30 keV, the characteristic frequencies of these components increase sharply with the energy, meaning that the high-energy component is more variable on short timescales. Our results suggest that the hot inner flow in MAXI J1820+070 is likely to be inhomogeneous. We propose a geometry with a truncated accretion disk and two Comptonization regions.

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“…For example in GX 339-4, Salvesen et al (2013) proposed that a variable hardening factor is an alternative to disk truncation, to explain changes in the disk spectrum. Other sources with possible evidence of variable hardening factor are 4U 1957+11 (Maitra et al 2014), MAXI J1820+070 (Guan et al 2021), and MAXI J1348−630 (Zhang et al 2022). From simulations of disk spectra, Merloni et al (2000) also suggested a variable hardening factor f col ≈ 1.7-3, arguing that f col increases when the disk emission is relatively less dominant.…”

Section: Evolution Of the Hardening Factormentioning

confidence: 99%

“…Numerical simulations (Shimura & Takahara 1995;Davis et al 2005;Shafee et al 2006) suggest a canonical value of f col ∼ 1.6 − 1.8. However, some studies suggest that the value of f col varies during the outburst evolution (e.g., Merloni et al 2000;Davis & El-Abd 2019;Guan et al 2021), especially in the LHS and HIMS (e.g., Dunn et al 2011;Salvesen et al 2013).…”

mentioning

confidence: 99%

Insight-HXMT Study of the Inner Accretion Disk in the Black Hole Candidate EXO 1846--031

Ren,

Wang,

Zhang

et al. 2022

Preprint

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We study the spectral evolution of the black hole candidate EXO 1846−031 during its 2019 outburst, in the 1-150 keV band, with the Hard X-ray Modulation Telescope. The continuum spectrum is well modelled with an absorbed disk-blackbody plus cutoff power-law, in the hard, intermediate and soft states. In addition, we detect an ≈6.6 keV Fe emission line in the hard intermediate state. Throughout the soft intermediate and soft states, the fitted inner disk radius remains almost constant; we suggest that it has settled at the innermost stable circular orbit (ISCO). However, in the hard and hard intermediate states, the apparent inner radius was unphysically small (smaller than ISCO), even after accounting for the Compton scattering of some of the disk photons by the corona in the fit. We argue that this is the result of a high hardening factor, f col ≈ 2.0 − 2.7, in the early phases of outburst evolution, well above the canonical value of 1.7 suitable to a steady disk. We suggest that the inner disk radius was close to ISCO already in the low/hard state. Furthermore, we propose that this high value of hardening factor in the relatively hard state is probably caused by the additional illuminating of the coronal irradiation onto the disk. Additionally, we estimate the spin parameter with the continuumfitting method, over a range of plausible black hole masses and distances. We compare our results with the spin measured with the reflection-fitting method and find that the inconsistency of the two results is partly caused by the different choices of f col .

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Physical origin of the non-physical spin evolution of MAXI J1820 + 070

Cited by 27 publications

References 62 publications

Analysis of the reflection spectra of MAXI J1535-571 in the hard and intermediate states

Analysis of the reflection spectra of MAXI J1535-571 in the hard and intermediate states

The Accretion Flow Geometry of MAXI J1820+070 through Broadband Noise Research with Insight Hard X-ray Modulation Telescope

Insight-HXMT Study of the Inner Accretion Disk in the Black Hole Candidate EXO 1846--031

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