Power spectral properties of the soft spectral states in four black hole transients

Mao, Dongming; Yu, Wenfei

doi:10.1088/1674-4527/21/7/170

Cited by 2 publications

(1 citation statement)

References 49 publications

(59 reference statements)

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“…When those sources complete their transition from the hard state to the soft state, their power spectra with narrow or smooth peaks will be substituted by a red-noise power spectra with f −1 slope (see e.g., Miyamoto et al 1994;Remillard & McClintock 2006;Ueda et al 2009;Klein-Wolt & van der Klis 2008;Mao & Yu 2021), although Cygnus X-1 generally shows a higher overall variability than transients in the the soft state (e.g., Heil et al 2015).…”

Section: Comparison With the Behaviors Of Other Bhbsmentioning

confidence: 99%

The spectral-timing analysis of Cygnus X-1 with Insight-HXMT

Zhou

Grinberg

et al. 2022

A&A

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Cygnus X-1, as the first discovered black hole binary, is a key source for understanding the mechanisms of state transitions, and the scenarios of accretion in extreme gravity fields. We present a spectral-timing analysis of observations taken with the Insight-HXMT mission, focusing on the spectral-state dependent timing properties in the broad energy range of 1-150 keV, thus extending previous RXTE-based studies to both lower and higher energies. Our main results are the following: a) We successfully use a simple empirical model to fit all spectra, confirming that the reflection component is stronger in the soft state than in the hard state; b) The evolution of the total fractional root mean square (rms) depends on the selected energy band and the spectral shape, which is a direct result of the evolution of the power spectral densities (PSDs); c) In the hard/intermediate state, we see clear short-term variability features and a positive correlation between central frequencies of the variability components and the soft photon index Γ 1 , also at energies above 15 keV. The power spectrum is dominated by red noise in the soft state instead. These behaviors can be traced to at least 90 keV; d) The coherence and the phase-lag spectra show different behaviors dependent on different spectral shapes.

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Section: Comparison With the Behaviors Of Other Bhbsmentioning

confidence: 99%

The spectral-timing analysis of Cygnus X-1 with Insight-HXMT

Zhou

Grinberg

et al. 2022

A&A

View full text Add to dashboard Cite

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Spectral and Timing Properties of H 1743-322 in the “Faint” 2005 Normal Outburst

et al. 2022

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H 1743-322 is a well-known black hole X-ray binary (BH XRBs) that has been observed in several outbursts over the past. In this work, we have performed the spectral and timing analysis of H 1743-322 during the “faint” 2005 outburst for the first time with the RXTE/PCA data. In this outburst, the spectral and timing parameters (e.g., Tin, Γ, Rin, rms and QPOs, etc.) presented an obvious change and a q-like pattern was found in the Hardness Intensity Diagram (HID), which often named as the hysteresis effect of BH XRBs. The radius of the innermost stable circular orbit was constrained as RISCO∼3.50 Rg, which predicts that H 1743-322 is a lower-spin black hole. We further explored the correlation between timing and spectral properties. The relation of photon index Γ and X-ray flux, F3–25keV, presented a transition between negative and positive correlation when the X-ray luminosity, L3–25keV, is above and below a critical X-ray luminosity, LX,crit≃2.55×10−3 LEdd, which can be well explained by the Shakura-Sunyaev disk–corona model (SSD-corona) and advection-dominated accretion flow (ADAF). We also found the tight linear, negative correlation between photon index Γ and the total fractional rms. Since the amount of soft photons from the accretion disk seems invariable, an increase of the number of soft photons will dilute the variability from the harder photons. Therefore, the softer the X-ray spectra will result in the smaller total fractional rms. The above results suggested that the 2005 outburst of H 1743-322 was a normal outburst and H 1743-322 represented similar properties with other black hole X-ray binaries.

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Power spectral properties of the soft spectral states in four black hole transients

Cited by 2 publications

References 49 publications

The spectral-timing analysis of Cygnus X-1 with Insight-HXMT

The spectral-timing analysis of Cygnus X-1 with Insight-HXMT

Spectral and Timing Properties of H 1743-322 in the “Faint” 2005 Normal Outburst

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