Accretion around black holes: The geometry and spectra

Liu, B.F.; Qiao, Erlin

doi:10.1016/j.isci.2021.103544

Cited by 25 publications

(10 citation statements)

References 112 publications

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“…The spectral analysis shows that the coronal temperature (kT e ) of the decay phase is obviously higher than that of the rise phase (see Figure 6(c)). If the corona is a hot accretion flow (e.g., advection-dominated accretion flow), it is mainly supported by the gas pressure (Narayan & Yi 1994;Yuan & Narayan 2014;Liu & Qiao 2022), and the height (h) could hence be lager with the higher coronal temperature. Accordingly, the corona in the decay phase could have a relatively larger h/r at a specific frequency, and then precesses with lower variability in amplitude.…”

Section: Tracing the Coronal Geometry Using The Simplified Lt Precess...mentioning

confidence: 99%

Tracing the Accretion Geometry of H1743-322 with Type C Quasiperiodic Oscillations in Multiple Outbursts

Shui

Zhang²,

Chen³

et al. 2023

ApJ

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We present a systematic analysis of type C quasiperiodic oscillation (QPO) observations of H1743-322 throughout the Rossi X-ray Timing Explorer era. We find that, while different outbursts have significant flux differences, they show consistent positive correlations between the QPO fractional rms amplitude and nonthermal fraction of the emission, which indicate an independence of the intrinsic QPO rms on individual outburst brightnesses in H1743-322. However, the dependence of the QPO rms on frequency is different between the outburst rise and decay phases, where the QPO fractional rms of the decay phase is significantly lower than that of the rise phase at low frequencies. The spectral analysis also reveals different ranges of coronal temperature between the two outburst stages. A semiquantitative analysis shows that the Lense–Thirring precession model could be responsible for the QPO rms differences, requiring a variable coronal geometric shape. However, the variable-Comptonization model could also account for the findings. The fact that the rms differences and the hysteresis traces in the hardness–intensity diagram accompany each other indicates a connection between the two phenomena. By correlating the findings with QPO phase lags and the quasi-simultaneous radio flux previously published, we propose there could be corona-jet transitions in H1743-322 similar to those that have been recently reported in GRS 1915+105.

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Section: Tracing the Coronal Geometry Using The Simplified Lt Precess...mentioning

confidence: 99%

Tracing the Accretion Geometry of H1743-322 with Type C Quasiperiodic Oscillations in Multiple Outbursts

Shui

Zhang²,

Chen³

et al. 2023

ApJ

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“…In the hard state of a BHXRB, a geometrically thick ADAF is thought to be located close to the BH, extending outward and connecting to a thin disk with a truncated inner radius R tr (equal to the ADAF radial extent) ( 29 , 30 ). We assumed that R tr = R ISCO at t 0 = MJD 58381 when the soft state ended, where R ISCO is the radius of the BH’s innermost stable circular orbit (ISCO).…”

Section: Interpretation Of the Radio Time Lagmentioning

confidence: 99%

Observations of a black hole x-ray binary indicate formation of a magnetically arrested disk

You,

Cao,

Yan

et al. 2023

Science

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Accretion of material onto a black hole drags any magnetic fields present inwards, increasing their strength. Theory predicts that sufficiently strong magnetic fields can halt the accretion flow, producing a magnetically arrested disk (MAD). We analyzed archival multiwavelength observations of an outburst from the black hole x-ray binary MAXI J1820+070 in 2018. The radio and optical fluxes were delayed compared with the x-ray flux by about 8 and 17 days, respectively. We interpret this as evidence for the formation of a MAD. In this scenario, the magnetic field is amplified by an expanding corona, forming a MAD around the time of the radio peak. We propose that the optical delay is due to thermal viscous instability in the outer disk.

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“…The correlation was also studied by analyzing RXTE/PCA data for GX 339-4 and Cyg X-1 hard state (Gilfanov et al 1999;Revnivtsev et al 2001), and for the sample of low-mass X-ray binaries (LMXBs; Steiner et al 2016). However, the physical interpretation of this correlation is still under debate, which might be either the evolution of the inner radius (Zdziarski et al 1999;Qiao & Liu 2017;Liu & Qiao 2022) in the scenario of the truncated disk, or the bulk velocity of the corona with respect to the disk (Beloborodov 1999). As for the correlation between L X and R, it was found that the R gradually increases as the source luminosity rises for GX 339-4 in the hard state, which was interpreted in the scenario of the truncated disk (Plant et al 2014).…”

Section: Introductionmentioning

confidence: 99%

X-Ray Spectral Correlations in a Sample of Low-mass Black Hole X-Ray Binaries in the Hard State

You

Dong

Yan

et al. 2023

ApJ

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The power-law emission and reflection component provide valuable insights into the accretion process around a black hole. In this work, thanks to the broadband spectra coverage of the Nuclear Spectroscopic Telescope Array, we study the spectral properties for a sample of low-mass black hole X-ray binaries (BHXRBs). We find that there is a positive correlation between the photon index Γ and the reflection fraction R (the ratio of the coronal intensity that illuminates the disk to the coronal intensity that reaches the observer), consistent with previous studies, but except for MAXI J1820+070. It is quite interesting that this source also deviates from the well-known “V”-shaped correlation between the photon index Γ and the X-ray luminosity log L X , when it is in the bright hard state. More specifically, the Λ-shaped correlation between Γ and logL X is observed, as the luminosity decreases by a factor of 3 in a narrow range from ∼1038 to 1037.5 erg s−1. Furthermore, we discover a strong positive correlation between R and the X-ray luminosity for BHXRBs in the hard state, which puts a constraint on the disk-corona coupling and the evolution.

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Accretion around black holes: The geometry and spectra

Cited by 25 publications

References 112 publications

Tracing the Accretion Geometry of H1743-322 with Type C Quasiperiodic Oscillations in Multiple Outbursts

Tracing the Accretion Geometry of H1743-322 with Type C Quasiperiodic Oscillations in Multiple Outbursts

Observations of a black hole x-ray binary indicate formation of a magnetically arrested disk

X-Ray Spectral Correlations in a Sample of Low-mass Black Hole X-Ray Binaries in the Hard State

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