NuSTAR AND SWIFT OBSERVATIONS OF THE VERY HIGH STATE IN GX 339-4: WEIGHING THE BLACK HOLE WITH X-RAYS

Parker, M. L.; Tomsick, John A.; Kennea, J. A.; Miller, J. M.; Harrison, Fiona A.; Barret, D.; Boggs, Steven E.; Christensen, Finn Erland; Craig, William W.; Fabian, A. C.; Fürst, F.; Grinberg, V.; Hailey, Charles J.; Romano, P.; Stern, Daniel; Walton, Dom; Zhang, W. W.

doi:10.3847/2041-8205/821/1/l6

Cited by 117 publications

(142 citation statements)

References 47 publications

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“…Lee & Carney (2006) find the metallicity in NGC 6293 is ∼ 1/100 of solar abundance. We were unable to explore a lower iron abundance due to the hard lower limit of the model (A F e = 0.5), however, anomalously high iron abundances have been seen in many reflection studies (e.g., Parker et al 2015Parker et al , 2016Füerst et al 2016;García et al 2015;Walton et al 2014Walton et al , 2016. It is possible that this high A F e measurement correctly describes the atmosphere of the accretion disk and not the overall abundances within the accretion flow due to the ionization structure skewing the relative abundances there.…”

Section: Spectral Analysis and Resultsmentioning

confidence: 99%

Relativistic Disk Reflection in the Neutron Star X-Ray BinaryXTE J1709-267 with NuSTAR

Ludlam

Miller

Cackett

et al. 2017

ApJ

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We perform the first reflection study of the soft X-ray transient and Type 1 burst source XTE J1709-267 using NuSTAR observations during its 2016 June outburst. There was an increase in flux near the end of the observations, which corresponds to an increase from ∼0.04 L Edd to ∼0.06 L Edd assuming a distance of 8.5 kpc. We have separately examined spectra from the low and high flux intervals, which were soft and show evidence of a broad Fe K line. Fits to these intervals with relativistic disk reflection models have revealed an inner disk radius of 13.82 ) for the low flux spectrum and 23.4−5.4 R g for the high flux spectrum at the 90% confidence level. The disk is likely truncated by a boundary layer surrounding the neutron star or the magnetosphere. Based on the measured luminosity and using the accretion efficiency for a disk around a neutron star, we estimate that the theoretically expected size for the boundary layer would be ∼ 0.9 − 1.1 R g from the neutron star's surface, which can be increased by spin or viscosity effects. Another plausible scenario is that the disk could be truncated by the magnetosphere. We place a conservative upper limit on the strength of the magnetic field at the poles, assuming a * = 0 and M N S = 1.4 M ⊙ , of B ≤ 0.75 − 3.70 × 10 9 G, though X-ray pulsations have not been detected from this source.

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Section: Spectral Analysis and Resultsmentioning

confidence: 99%

Relativistic Disk Reflection in the Neutron Star X-Ray BinaryXTE J1709-267 with NuSTAR

Ludlam

Miller

Cackett

et al. 2017

ApJ

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“…However, in most cases, the change in the inner disk radius measured at multiple epochs is only marginally significant, and can often be considered as consistent within errors. The best cases regarding variations in the Fe Kα line profile are the narrow lines detected in the very low states of GX 339-4 (Tomsick et al 2009) and V404 Cygni (Motta et al 2017), given that relativistically broadened lines are known to be present in their high states (e.g., Parker et al 2016;Walton et al 2017). We note that in the previous cases the Fe Kα lines are sufficiently narrow and symmetric that they do not require general relativity effects to explain, signaling a line emission region at a large distance of 10 2 − 10 3 r g .…”

Section: The Iron Line Profile and Disk Truncationmentioning

confidence: 99%

“…Assuming that the innermost disk radius is associated with the innermost stable circular orbit (ISCO) around the black hole, we can directly estimate the spin of the black hole. Recently, with high sensitivity and broadband spectral coverage, NuSTAR detected strong relativistic reflection features in several known or new black hole X-ray binaries or binary candidates, where the broad iron line profiles are resolved (e.g., Tomsick et al 2014;Miller et al 2015;Parker et al 2016;Walton et al 2017;Xu et al 2018a,b;Buisson et al 2019). These high-quality datasets of bright black hole X-ray binaries are free from pileup distortions and enable detailed studies of the inner accretion flow of black holes based on the diagnostics of relativistic disk reflection features.…”

Section: Introductionmentioning

confidence: 99%

Studying the Reflection Spectra of the New Black Hole X-Ray Binary Candidate MAXI J1631−479 Observed by NuSTAR: A Variable Broad Iron Line Profile

Harrison

Tomsick

et al. 2020

ApJ

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We present results from the Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the new black hole X-ray binary candidate MAXI J1631-479 at two epochs during its 2018-2019 outburst, which caught the source in a disk dominant state and a power-law dominant state. Strong relativistic disk reflection features are clearly detected, displaying significant variations in the shape and strength of the broad iron emission line between the two states. Spectral modeling of the reflection spectra reveals that the inner radius of the opticallythick accretion disk evolves from < 1.9 r g to 12 ± 1 r g (statistical errors at 90% confidence level) from the disk dominant to the power-law dominant state. Assuming in the former case that the inner disk radius is consistent with being at the ISCO, we estimate a black hole spin of a * > 0.94. Given that the bolometric luminosity is similar in the two states, our results indicate that the disk truncation observed in MAXI J1631-479 in the power-law dominant state is unlikely to be driven by a global variation in the accretion rate. We propose that it may instead arise from local instabilities in the inner edge of the accretion disk at high accretion rates. In addition, we find an absorption feature in the spectra centered at 7.33 ± 0.03 keV during the disk dominant state, which is evidence for a rare case that an extremely fast disk wind (v out = 0.067 +0.001 −0.004 c) is observed in a low-inclination black hole binary, with the viewing angle of 29 ± 1 • as determined by the reflection modeling.

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“…One notable effort by Petrucci et al (2001) explored the effect of coronal Comptonization on the reflection continuum flux and Compton hump, but in general this has gone unexplored. A handful of similar efforts have taken steps toward self-consistent treatment of the thermal and nonthermal spectral components-notably using EQPAIR (Coppi 1999; e.g., Kubota & Done 2016) or COMPPS (Poutanen & Svensson 1996), and to lesser degree in Parker et al (2016), Basak & Zdziarski (2016), Plant et al (2015), Tomsick et al (2014), Steiner et al (2011), Miller et al (2009. But an advanced self-consistent approach has not been realized.…”

Section: Introductionmentioning

confidence: 99%

Self-consistent Black Hole Accretion Spectral Models and the Forgotten Role of Coronal Comptonization of Reflection Emission

Steiner

García

Eikmann

et al. 2017

ApJ

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Continuum and reflection spectral models have each been widely employed in measuring the spins of accreting black holes. However, the two approaches have not been implemented together in a photon-conserving, selfconsistent framework. We develop such a framework using the black hole X-ray binary GX339-4 as a touchstone source, and we demonstrate three important ramifications.(1) Compton scattering of reflection emission in the corona is routinely ignored, but is an essential consideration given that reflection is linked to the regimes with strongest Comptonization. Properly accounting for this causes the inferred reflection fraction to increase substantially, especially for the hard state. Another important impact of the Comptonization of reflection emission by the corona is the downscattered tail. Downscattering has the potential to mimic the relativistically broadened red wing of the Fe line associated with a spinning black hole. (2) Recent evidence for a reflection component with a harder spectral index than the power-law continuum is naturally explained as Compton-scattered reflection emission. (3) Photon conservation provides an important constraint on the hard state's accretion rate. For bright hard states, we show that disk truncation to large scales  R R ISCO is unlikely as this would require accretion rates far in excess of the observed Ṁ of the brightest soft states. Our principal conclusion is that when modeling relativistically broadened reflection, spectral models should allow for coronal Compton scattering of the reflection features, and when possible, take advantage of the additional constraining power from linking to the thermal disk component.

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NuSTAR AND SWIFT OBSERVATIONS OF THE VERY HIGH STATE IN GX 339-4: WEIGHING THE BLACK HOLE WITH X-RAYS

Cited by 117 publications

References 47 publications

Relativistic Disk Reflection in the Neutron Star X-Ray BinaryXTE J1709-267 with NuSTAR

Relativistic Disk Reflection in the Neutron Star X-Ray BinaryXTE J1709-267 with NuSTAR

Studying the Reflection Spectra of the New Black Hole X-Ray Binary Candidate MAXI J1631−479 Observed by NuSTAR: A Variable Broad Iron Line Profile

Self-consistent Black Hole Accretion Spectral Models and the Forgotten Role of Coronal Comptonization of Reflection Emission

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