“…The corona in the lamppost geometry, should be interpreted as a jet base, possibly a standing shock 40 , and was discussed in a number of previous studies of AGN and BH X-ray binary in the low/hard state 41 ; this probably provides a physical interpretation to the compact X-ray jet revealed by the timing analysis of the same Insight-HXMT data used here 27 . The evolution of the outflowing corona should be studied in terms of both its position and bulk velocity, which can help us to better understand the acceleration/deceleration of the particles near a BH.…”
Section: Resultsmentioning
confidence: 63%
“…In this decay, the source mainly stayed in the soft state in which the LE photon rates dominated over ME/HE photon rates. The same Insight-HXMT observations have been used recently to study the timing properties of the outburst and LFQPOs were discovered above 200 keV, which was interpreted as due to the precession of a twisted compact X-ray jet 27 . Fig.…”
A black hole X-ray binary produces hard X-ray radiation from its corona and disk when the accreting matter heats up. During an outburst, the disk and corona co-evolves with each other. However, such an evolution is still unclear in both its geometry and dynamics. Here we report the unusual decrease of the reflection fraction in MAXI J1820+070, which is the ratio of the coronal intensity illuminating the disk to the coronal intensity reaching the observer, as the corona is observed to contrast during the decay phase. We postulate a jet-like corona model, in which the corona can be understood as a standing shock where the material flowing through. In this dynamical scenario, the decrease of the reflection fraction is a signature of the corona’s bulk velocity. Our findings suggest that as the corona is observed to get closer to the black hole, the coronal material might be outflowing faster.
“…The corona in the lamppost geometry, should be interpreted as a jet base, possibly a standing shock 40 , and was discussed in a number of previous studies of AGN and BH X-ray binary in the low/hard state 41 ; this probably provides a physical interpretation to the compact X-ray jet revealed by the timing analysis of the same Insight-HXMT data used here 27 . The evolution of the outflowing corona should be studied in terms of both its position and bulk velocity, which can help us to better understand the acceleration/deceleration of the particles near a BH.…”
Section: Resultsmentioning
confidence: 63%
“…In this decay, the source mainly stayed in the soft state in which the LE photon rates dominated over ME/HE photon rates. The same Insight-HXMT observations have been used recently to study the timing properties of the outburst and LFQPOs were discovered above 200 keV, which was interpreted as due to the precession of a twisted compact X-ray jet 27 . Fig.…”
A black hole X-ray binary produces hard X-ray radiation from its corona and disk when the accreting matter heats up. During an outburst, the disk and corona co-evolves with each other. However, such an evolution is still unclear in both its geometry and dynamics. Here we report the unusual decrease of the reflection fraction in MAXI J1820+070, which is the ratio of the coronal intensity illuminating the disk to the coronal intensity reaching the observer, as the corona is observed to contrast during the decay phase. We postulate a jet-like corona model, in which the corona can be understood as a standing shock where the material flowing through. In this dynamical scenario, the decrease of the reflection fraction is a signature of the corona’s bulk velocity. Our findings suggest that as the corona is observed to get closer to the black hole, the coronal material might be outflowing faster.
“…Our results serve as a guide for future developments of Comptonisation models. Our model could be tested with spectral-timing data of the Type-B QPO in a wider energy range, for instance, using simultaneous data from NICER and HXMT, which covers up to 100 keV (Ma et al 2020). In this sense, this paper is a step towards the goal of building physically-motivated models capable to fit simultaneously the time-averaged and variability spectra of LMXBs at different frequencies.…”
Spectral-timing analysis of the fast variability observed in X-rays is a powerful tool to study the physical and geometrical properties of the accretion/ejection flows in black hole (BH) binaries. The origin of type-B quasi-periodic oscillations (QPO), predominantly observed in BH candidates in the soft-intermediate state, has been linked to emission arising from the relativistic jet. In this state, the X-ray spectrum is characterized by a soft-thermal blackbody-like emission due to the accretion disc, an iron emission line (in the 6–7 keV range), and a power-law-like hard component due to inverse-Compton scattering of the soft-photon source by hot electrons in a corona or the relativistic jet itself. The spectral-timing properties of MAXI J1348−630 have been recently studied using observations obtained with the NICER observatory. The data show a strong type-B QPO at ∼4.5 Hz with increasing fractional rms amplitude with energy and positive lags with respect to a reference band at 2–2.5 keV. We use a variable-Comptonization model that assumes a sinusoidal coherent oscillation of the Comptonized X-ray flux and the physical parameters of the corona at the QPO frequency, to fit simultaneously the energy-dependent fractional rms amplitude and phase lags of this QPO. We show that two physically connected Comptonization regions can successfully explain the radiative properties of the QPO in the full 0.8–10 keV energy range.
“…Also in the frame of Lense-Thirring precession, Ingram et al (2009) considered the precession of the hot flow inside a truncated disk and were able to explain why the observed maximum frequency is almost constant for all black hole XRBs. These models have been further extended and applied to observation data (Varnière & Tagger 2002;Titarchuk & Fiorito 2004;Cabanac et al 2010;Ingram & Done 2011;Varnière et al 2012;Veledina et al 2013;Karpouzas et al 2020;Ma et al 2020). However, we have not reached a unified model that can explain all QPO behaviors.…”
Section: Testing Evolution Of Lfqpos With Mass Accretion Rate In Grs 1915+105 Withmentioning
Using the Insight-HXMT observations of GRS 1915+105 when it exhibits low-frequency quasiperiodic oscillations (QPOs), we measure the evolution of the QPO frequency along with disk inner radius and mass accretion rate. We find a tight positive correlation between the QPO frequency and mass accretion rate. Our results extend the finding of previous work with AstroSat to a larger range of accretion rates with independent instruments and observations. Treating the QPO frequency of GRS 1915+105 as the relativistic dynamic frequency of a truncated disk, we are able to confirm the high spin nature of the black hole in GRS 1915+105. We also address the potential of our finding to test general relativity in the future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
