scholarly journals Super-Eddington Accretion in Black Hole X-Ray Binaries

2004 ◽  
Vol 194 ◽  
pp. 60-62
Author(s):  
M. R. Truss
Keyword(s):  
Black Hole ◽  
High Resolution ◽  
Mass Loss ◽  
Accretion Discs ◽  
X Ray ◽  
Extreme Variability ◽  
Hydrodynamical Simulations ◽  
X Ray Binaries ◽  
Eddington Limit ◽  
Very High

AbstractI present, very high resolution hydrodynamical simulations of accretion discs in black hole X-ray binaries accreting near the Eddington limit, including the effects of disc irradiation and mass loss. I show that the extreme variability displayed by sources such as GRS 1915+105 can be explained within the framework of an outburst in a partially irradiated, turbulent, disc.

scholarly journals Super-Eddington accretion discs with advection and outflows around magnetized neutron stars

2019 ◽  
Vol 626 ◽  
pp. A18 ◽  
Author(s):  
Anna Chashkina ◽  
Galina Lipunova ◽  
Pavel Abolmasov ◽  
Juri Poutanen
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Mass Loss ◽  
Accretion Rate ◽  
Accretion Disc ◽  
Accretion Discs ◽  
X Ray ◽  
Radial Profiles ◽  
X Ray Binaries ◽  
Eddington Limit

We present a model for a super-Eddington accretion disc around a magnetized neutron star taking into account advection of heat and the mass loss by the wind. The model is semi-analytical and predicts radial profiles of all the basic physical characteristics of the accretion disc. The magnetospheric radius is found as an eigenvalue of the problem. When the inner disc is in radiation-pressure-dominated regime but does not reach its local Eddington limit, advection is mild, and the radius of the magnetosphere depends weakly on the accretion rate. Once it approaches the local Eddington limit the disc becomes advection-dominated, and the scaling for the magnetospheric radius with the mass accretion rate is similar to the classical Alfvén relation. Allowing for the mass loss in a wind leads to an increase in the magnetospheric radius. Our model can be applied to a wide variety of magnetized neutron stars accreting close to or above their Eddington limits: ultra-luminous X-ray pulsars, Be/X-ray binaries in outbursts, and other systems. In the context of our model we discuss the observational properties of NGC 5907 X-1, the brightest ultra-luminous pulsar currently known, and NGC 300 ULX1, which is apparently a Be/X-ray binary experiencing a very bright super-Eddington outburst.

scholarly journals Mass transfer on a nuclear timescale in models of supergiant and ultra-luminous X-ray binaries

2019 ◽  
Vol 628 ◽  
pp. A19 ◽  
Author(s):  
M. Quast ◽  
N. Langer ◽  
T. M. Tauris
Keyword(s):  
Mass Transfer ◽  
Black Hole ◽  
Neutron Star ◽  
Roche Lobe ◽  
High Mass ◽  
X Rays ◽  
X Ray ◽  
Mass Ratios ◽  
X Ray Binaries ◽  
Eddington Limit

Context. The origin and number of the Galactic supergiant X-ray binaries is currently not well understood. They consist of an evolved massive star and a neutron star or black-hole companion. X-rays are thought to be generated from the accretion of wind material donated by the supergiant, while mass transfer due to Roche-lobe overflow is mostly disregarded because the high mass ratios of these systems are thought to render this process unstable. Aims. We investigate how the proximity of supergiant donor stars to the Eddington limit, and their advanced evolutionary stage, may influence the evolution of massive and ultra-luminous X-ray binaries with supergiant donor stars (SGXBs and ULXs). Methods. We constructed models of massive stars with different internal hydrogen and helium gradients (H/He gradients) and different hydrogen-rich envelope masses, and exposed them to slow mass-loss to probe the response of the stellar radius. In addition, we computed the corresponding Roche-lobe overflow mass-transfer evolution with our detailed binary stellar evolution code, approximating the compact objects as point masses. Results. We find that a H/He gradient in the layers beneath the surface, as it is likely present in the well-studied donor stars of observed SGBXs, can enable mass transfer in SGXBs on a nuclear timescale with a black-hole or a neutron star accretor, even for mass ratios in excess of 20. In our binary evolution models, the donor stars rapidly decrease their thermal equilibrium radius and can therefore cope with the inevitably strong orbital contraction imposed by the high mass ratio. We find that the orbital period derivatives of our models agree well with empirical values. We argue that the SGXB phase may be preceded by a common-envelope evolution. The envelope inflation near the Eddington limit means that this mechanism more likely occurs at high metallicity. Conclusion. Our results open a new perspective for understanding that SGBXs are numerous in our Galaxy and are almost completely absent in the Small Magellanic Cloud. Our results may also offer a way to find more ULX systems, to detect mass transfer on nuclear timescales in ULX systems even with neutron star accretors, and shed new light on the origin of the strong B-field in these neutron stars.

scholarly journals Chemical Abundances of the Secondary Stars in the Black Hole Binary A0620-00 and the Neutron Star Binary Cen X-4

2004 ◽  
Vol 194 ◽  
pp. 204-204
Author(s):  
J. I. González-Hernández ◽  
R. Rebolo ◽  
G. Israelian ◽  
J. Casares
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
High Resolution ◽  
Compact Object ◽  
Accretion Disc ◽  
Accretion Discs ◽  
Chemical Abundances ◽  
X Ray ◽  
Black Hole Binary ◽  
Star Binary

We have determined abundances in the secondary stars of the black hole X-ray binary A0620-00 and the neutron star Binary Cen X-4. These are K type stars veiled by the emission produced by the respective accretion discs. We searched for evidence of nucleosynthetic products from the progenitor of the compact object that could have contaminated the secondary stars (as in Israelian et al., 1999).Using high resolution spectra obtained with VLT/UVES, we have derived in a consistent way stellar parameters and the veiling caused by the accretion disc.

scholarly journals Possible ∼0.4 h X-ray quasi-periodicity from an ultrasoft active galactic nucleus

2020 ◽  
Vol 644 ◽  
pp. L9
Author(s):  
J. R. Song ◽  
X. W. Shu ◽  
L. M. Sun ◽  
Y. Q. Xue ◽  
C. Jin ◽  
...  
Keyword(s):  
Black Hole ◽  
Active Galactic Nucleus ◽  
Quiescent State ◽  
Black Hole Mass ◽  
Resonance Model ◽  
X Ray ◽  
Galactic Black Hole ◽  
Independent Observations ◽  
Extreme Variability ◽  
X Ray Binaries

RX J1301.9+2747 is an ultrasoft active galactic nucleus (AGN) with unusual X-ray variability that is characterized by a long quiescent state and a short-lived flare state. The X-ray flares are found to recur quasi-periodically on a timescale of 13−20 ks. Here, we report the analysis of the light curve in the quiescent state from two XMM-Newton observations spanning 18.5 years, along with the discovery of a possible quasi-periodic X-ray oscillation (QPO) with a period of ∼1500 s. The QPO is detected at the same frequency in the two independent observations, with a combined significance of > 99.89%. The QPO is in agreement with the relation between frequency and black hole mass (MBH) that has been reported in previous works for AGNs and Galactic black hole X-ray binaries (XRBs). The QPO frequency is stable over almost two decades, suggesting that it may correspond to the high-frequency type found in XRBs and originates, perhaps, from a certain disk resonance mode. In the 3:2 twin-frequency resonance model, our best estimate on the MBH range implies that a maximal black hole spin can be ruled out. We find that all ultrasoft AGNs reported so far display quasi-periodicities in the X-ray emission, suggesting a possible link on the part of the extreme variability phenomenon to the ultrasoft X-ray component. This indicates that ultrasoft AGNs could be the most promising candidates in future searches for X-ray periodicities.

scholarly journals The impact of thermal winds on the outburst lightcurves of black hole X-ray binaries

2019 ◽  
Vol 632 ◽  
pp. A40 ◽  
Author(s):  
Guillaume Dubus ◽  
Chris Done ◽  
Bailey E. Tetarenko ◽  
Jean-Marie Hameury
Keyword(s):  
Black Hole ◽  
Mass Loss ◽  
Accretion Rate ◽  
Strong Wind ◽  
X Rays ◽  
X Ray ◽  
Thermal Wind ◽  
Viscous Instability ◽  
The Impact ◽  
X Ray Binaries

Context. The observed signatures of winds from X-ray binaries are broadly consistent with thermal winds, which are driven by X-ray irradiation of the outer accretion disc. Thermal winds produce mass outflow rates that can exceed the accretion rate in the disc. Aims. We aim to study the impact of thermal wind mass loss on the stability and lightcurves of black hole X-ray binaries subject to the thermal-viscous instability driving their outbursts. Strong mass loss could stop outbursts early, as proposed for the 2015 outburst of V404 Cyg. Methods. We used an analytical model for thermal (Compton) wind mass loss as a function of radius, X-ray spectrum, and luminosity that was calibrated against numerical simulations. We also estimated the fraction of the X-rays, emitted close to the compact object, that are scattered back to the outer disc in the wind. Scattering in the thermal wind couples irradiation to the disc size and inner mass accretion rate. The disc evolution equations were modified to include this wind mass loss and the varying irradiation fraction. Results. Scattering in the strong wind expected of long Porb systems enhances the irradiation heating of the outer disc, keeping it stable against the thermal-viscous instability. This accounts very well for the existence of persistently bright systems with large discs, such as Cyg X-2, 1E 1740.7−2942, or GRS 1758−258. Mass loss from the thermal wind shortens the outburst, as expected, but it is insufficient in explaining the rapid decay timescale of black-hole X-ray binary outbursts. However, including the wind-related varying irradiation fraction produces lightcurves with plateaus in long Porb systems like GRO J1655−40. Plateau lightcurves may be a dynamical signature of enhanced irradiation due to scattering in thermal winds. Conclusions. Mass loss due to thermal winds is not a major driver for the outburst dynamics up to luminosities of 0.1 − 0.2 LEdd. Higher luminosities may produce stronger mass loss but studying them is complicated since the wind becomes opaque. Magnetic winds, which extract angular momentum with little mass loss, seem more promising to explain the fast decay timescales generically seen in black-hole X-ray binaries. Thermal winds can play an important role in the outburst dynamics through the varying irradiation heating. This may be evidenced by relating changes in wind properties, X-ray spectra, or luminosity with changes in the optical emission that traces the outer disc. Simulations should enable more accurate estimates of the dependence of the irradiation onto the disc as a function of irradiation spectrum, radius, and disc wind properties.

scholarly journals Jet production efficiency in the sample of the youngest radio galaxies

2018 ◽  
Vol 14 (S342) ◽  
pp. 278-279
Author(s):  
Anna Wójtowicz ◽  
Łukasz Stawarz ◽  
Emily Kosmaczewski
Keyword(s):  
Black Hole ◽  
High Resolution ◽  
Production Efficiency ◽  
Radio Galaxies ◽  
Fundamental Plane ◽  
X Ray ◽  
Jet Production ◽  
Radiative Efficiency ◽  
Accretion Rates ◽  
Very High

AbstractWe investigate the sample of 16 the youngest radio galaxies with measured kinematic ages and available X-ray data from high-resolution Chandra or XMM-Newton observations. We characterize the accretion properties and derive the jet kinetic luminosities for our sources. We found high accretion rates (>1% Eddington) and very high jet production efficiency for all the sources from our sample.This, along with the fact that the analyzed objects seem over-luminous in radio on the fundamental plane for the black hole activity, implies also that the radiative efficiency of the compact lobes is much higher than in the case of the evolved radio galaxies.

scholarly journals SS433 and the nature of ultra-luminous X-ray sources

2006 ◽  
Vol 2 (S238) ◽  
pp. 219-224
Author(s):  
P. A. Charles ◽  
A. D. Barnes ◽  
J. Casares ◽  
J. S. Clark ◽  
R. Cornelisse ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
High Resolution ◽  
Binary System ◽  
Compact Object ◽  
High Mass ◽  
X Ray ◽  
New Class ◽  
The Galaxy ◽  
X Ray Binaries

AbstractThe prototypical micro-quasar, SS433, one of the most bizarre objects in the Galaxy, is a weak X-ray source, yet the kinetic energy of its relativistic, precessing jets is vastly greater. In spite of its importance as the nearest example of directly observable relativistic phenomena, we know remarkably little about the nature of this binary system. There are ongoing arguments not only about the mass of the compact object, but even as to whether it is a black hole or a neutron star, an argument that recent high resolution optical spectroscopy has contributed to.Combined with the INTEGRAL discovery of a new class of highly obscured galactic high-mass X-ray binaries, one of which has been found to precess on a similar timescale to SS433, we suggest that these would indeed be seen by external observers as ULXs, once additional effects such as beaming (either relativistic or geometrical) are included.

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