scholarly journals Wind Roche lobe overflow in high-mass X-ray binaries

2019 ◽  
Vol 622 ◽  
pp. L3 ◽  
Author(s):  
I. El Mellah ◽  
J. O. Sundqvist ◽  
R. Keppens
Keyword(s):  
Mass Transfer ◽  
Compact Object ◽  
Stellar Mass ◽  
Roche Lobe ◽  
High Mass ◽  
Transfer Rates ◽  
X Ray ◽  
Accretion Rates ◽  
Mass Outflow ◽  
X Ray Binaries

Ultraluminous X-ray sources (ULXs) have such high X-ray luminosities that they were long thought to be accreting intermediate-mass black holes. Yet, some ULXs have been shown to display periodic modulations and coherent pulsations suggestive of a neutron star in orbit around a stellar companion and accreting at super-Eddington rates. In this Letter, we propose that the mass transfer in ULXs could be qualitatively the same as in supergiant X-ray binaries (SgXBs), with a wind from the donor star highly beamed towards the compact object. Since the star does not fill its Roche lobe, this mass transfer mechanism known as “wind Roche lobe overflow” can remain stable even for large donor-star-to-accretor mass ratios. Based on realistic acceleration profiles derived from spectral observations and modeling of the stellar wind, we compute the bulk motion of the wind to evaluate the fraction of the stellar mass outflow entering the region of gravitational predominance of the compact object. The density enhancement towards the accretor leads to mass-transfer rates systematically much larger than the mass-accretion rates derived by the Bondi-Hoyle-Lyttleton formula. We identify orbital and stellar conditions for a SgXBs to transfer mass at rates necessary to reach the ULX luminosity level. These results indicate that Roche-lobe overflow is not the only way to funnel large quantities of material into the Roche lobe of the accretor. With the stellar mass-loss rates and parameters of M101 ULX-1 and NGC 7793 P13, wind Roche-lobe overflow can reproduce mass-transfer rates that qualify an object as an ULX.

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 Stellar Winds in Massive X-ray Binaries

2016 ◽  
Vol 12 (S329) ◽  
pp. 355-358
Author(s):  
Peter Kretschmar ◽  
Silvia Martínez-Núñez ◽  
Enrico Bozzo ◽  
Lidia M. Oskinova ◽  
Joachim Puls ◽  
...  
Keyword(s):  
Compact Object ◽  
High Mass ◽  
Stellar Winds ◽  
X Rays ◽  
X Ray ◽  
Current State ◽  
Wide Range ◽  
Strong Winds ◽  
The One ◽  
X Ray Binaries

AbstractStrong winds from massive stars are a topic of interest to a wide range of astrophysical fields. In High-Mass X-ray Binaries the presence of an accreting compact object on the one side allows to infer wind parameters from studies of the varying properties of the emitted X-rays; but on the other side the accretor’s gravity and ionizing radiation can strongly influence the wind flow. Based on a collaborative effort of astronomers both from the stellar wind and the X-ray community, this presentation attempts to review our current state of knowledge and indicate avenues for future progress.

scholarly journals High mass X-ray binaries as progenitors of gravitational wave sources

2018 ◽  
Vol 14 (S346) ◽  
pp. 417-425 ◽  
Author(s):  
Jakub Klencki ◽  
Gijs Nelemans
Keyword(s):  
Mass Transfer ◽  
Massive Star ◽  
Formation Rate ◽  
Point Of View ◽  
High Mass ◽  
Close Binary ◽  
X Ray ◽  
Orbital Periods ◽  
X Ray Binaries ◽  
Hubble Time

AbstractX-ray binaries with black hole (BH) accretors and massive star donors at short orbital periods of a few days can evolve into close binary BH (BBH) systems that merge within the Hubble time. From an observational point of view, upon the Roche-lobe overflow such systems will most likely appear as ultra-luminous X-ray sources (ULXs). To study this connection, we compute the mass transfer phase in systems with BH accretors and massive star donors (M > 15 Mʘ) at various orbital separations and metallicities. In the case of core-hydrogen and core-helium burning donors (cases A and C of mass transfer) we find the typical duration of super-Eddington mass transfer of up to 106 and 105 yr, with rates of 10−6 and 10−5Mʘ yr-1, respectively. Given that roughly 0.5 ULXs are found per unit of star formation rate, we estimate the rate of BBH mergers from stable mass transfer evolution to be at most 10 Gpc−3 yr−1.

Modeling of hydrodynamic processes within high-mass X-ray binaries

2018 ◽  
Vol 14 (S346) ◽  
pp. 197-201
Author(s):  
Petr Kurfürst ◽  
Jiří Krtička
Keyword(s):  
Mass Loss Rate ◽  
Compact Object ◽  
Supernova Explosion ◽  
High Mass ◽  
Be Stars ◽  
X Ray ◽  
Hydrodynamic Processes ◽  
Hydrodynamic Structure ◽  
X Ray Binaries ◽  
Circumstellar Environment

AbstractHigh-mass X-ray binaries belong to the brightest objects in the X-ray sky. They usually consist of a massive O or B star or a blue supergiant while the compact X-ray emitting component is a neutron star (NS) or a black hole. Intensive matter accretion onto the compact object can take place through different mechanisms: wind accretion, Roche-lobe overflow, or circumstellar disk. In our multi-dimensional models we perform numerical simulations of the accretion of matter onto a compact companion in case of Be/X-ray binaries. Using Bondi-Hoyle-Littleton approximation, we estimate the NS accretion rate. We determine the Be/X-ray binary disk hydrodynamic structure and compare its deviation from isolated Be stars’ disk. From the rate and morphology of the accretion flow and the X-ray luminosity we improve the estimate of the disk mass-loss rate. We also study the behavior of a binary system undergoing a supernova explosion, assuming a blue supergiant progenitor with an aspherical circumstellar environment.

scholarly journals The Average X-Ray Lifetime of Massive X-Ray Binaries

1986 ◽  
Vol 116 ◽  
pp. 383-384
Author(s):  
Paul Hellings
Keyword(s):  
Mass Transfer ◽  
Stellar Wind ◽  
Roche Lobe ◽  
P Systems ◽  
X Ray ◽  
X Ray Binaries

Massive X-ray binaries may be powered by two mechanisms generating X-radiation: accretion of stellar wind material of the O-star, or Roche lobe overflow (RLOF). The evolution of RLOF powered X-ray binaries has been studied by Savonije (1978). For massive binaries the duration of the RLOF powered stage is less than 100 years for binaries evolving through case B of mass transfer, and 5000 to 10 000 years for case A. On this basis Savonije concluded that the majority of the X-ray binaries should evolve through case A of mass transfer, in order to explain the observed number of active sources in massive binaries. In this study we compute the transition from compact+P systems into X-ray binaries, with emphasis on the wind powered stage.

scholarly journals Color–color diagrams as tools for assessment of the variable absorption in high mass X-ray binaries

2020 ◽  
Vol 643 ◽  
pp. A109
Author(s):  
V. Grinberg ◽  
M. A. Nowak ◽  
N. Hell
Keyword(s):  
Stellar Wind ◽  
Binary Systems ◽  
Compact Object ◽  
Spectral Shape ◽  
High Mass ◽  
Line Of Sight ◽  
Current Generation ◽  
X Ray ◽  
Partial Covering ◽  
X Ray Binaries

High mass X-ray binaries hold the promise of allowing us to understand the structure of the winds of their supermassive companion stars by using the emission from the compact object as a backlight to evaluate the variable absorption in the structured stellar wind. The wind along the line of sight can change on timescales as short as minutes and below. However, such short timescales are not available for the direct measurement of absorption through X-ray spectroscopy with the current generation of X-ray telescopes. In this paper, we demonstrate the usability of color–color diagrams for assessing the variable absorption in wind accreting high mass X-ray binary systems. We employ partial covering models to describe the spectral shape of high mass X-ray binaries and assess the implication of different absorbers and their variability on the shape of color–color tracks. We show that in taking into account, the ionization of the absorber, and in particular accounting for the variation of ionization with absorption depth, is crucial to describe the observed behavior well.

Vertical distribution of HMXBs in NGC 55: constraining their centre-of-mass velocity

2020 ◽  
Vol 493 (4) ◽  
pp. 5369-5381 ◽  
Author(s):  
Babis Politakis ◽  
Andreas Zezas ◽  
Jeff J Andrews ◽  
Stephen J Williams
Keyword(s):  
Vertical Distribution ◽  
Compact Object ◽  
Supernova Explosion ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
High Mass ◽  
Centre Of Mass ◽  
X Ray ◽  
X Ray Binaries ◽  
The Vertical Distribution

ABSTRACT We analyse the vertical distribution of high-mass X-ray binaries (HMXBs) in NGC 55, the nearest edge-on galaxy to the Milky Way (MW), based on X-ray observations by Chandra. Adopting a statistical approach, we estimate the difference between the scale height of the vertical distribution of HMXBs and the vertical distribution of star-forming activity between 0.33 and 0.57 kpc. The spatial offsets can be explained by a momentum kick the X-ray binaries receive during the formation of the compact object after a supernova explosion of the primary star. Determining the vertical distribution of HMXBs in the MW using Gaia DR2 astrometry, we find that the corresponding difference is considerably lower at 0.036 ± 0.003 kpc, attributed to the greater gravitational potential of the MW. We also calculate the centre-of-mass transverse velocities of HMXBs in NGC 55, using traveltime information from binary population synthesis codes and for different star formation histories (SFHs). For a flat SFH model (typical of spiral galaxies like NGC 55), we find that HMXBs are moving with a typical transverse velocity between 34 and 48 km s−1, consistent with space velocities of MW HMXBs. For an exponentially declining SFH model, HMXBs are moving at a velocity of 21 km s−1, consistent with the corresponding velocity of HMXBs in the Small Magellanic Cloud and Large Magellanic Cloud. Finally, we estimate the formation efficiency of HMXBs in NGC 55 at 299$_{-46}^{+50}$ (systems/M⊙ yr−1), consistent within the errors with the Magellanic Clouds but significantly higher than the MW, a difference that can be explained by the subsolar metallicity of NGC 55.

Probing the building blocks of galaxies: Sub-galactic scaling relations between X-ray luminosity, SFR and stellar mass

2019 ◽  
Vol 15 (S341) ◽  
pp. 162-166
Author(s):  
K. Kouroumpatzakis ◽  
A. Zezas ◽  
P. H. Sell ◽  
P. Bonfini ◽  
M. L. N. Ashby ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Building Blocks ◽  
Stellar Mass ◽  
High Mass ◽  
Scaling Relations ◽  
Local Universe ◽  
X Ray ◽  
Star Formation Activity ◽  
X Ray Binaries

AbstractIt is well known that X-ray luminosity (Lx) originating from high mass X-ray binaries (HMXBs) is tightly correlated with the host galaxy’s star formation rate (SFR). We explore this connection using a sample representative of the star-formation activity in the local Universe (Star-Formation Reference Survey; SFRS) along with a comprehensive set of star-formation (radio, FIR, 24μm, 8 μm, Hα, UV, SED fitting) and stellar mass (K-band, 3.6 μm, SED fitting) indicators, and Chandra observations. We investigate the Lx–SFR and Lx– stellar mass (M*) scaling relations down to sub-galactic scales of ∼lkpc2. This way we extend these relations to extremely low SFR (∼10−6M⊙.yr−1) and M* (∼104M⊙). We also quantify their scatter and their dependence on the age of the local stellar populations as inferred from the different age sensitive SFR indicators. These results are particularly important for setting the benchmark for the formation of X-ray binaries in vigorous, but low SFR objects such as galaxies in the early Universe.

scholarly journals Ultra-compact X-ray binaries with high luminosity: a key for a new scenario

2012 ◽  
Vol 8 (S291) ◽  
pp. 468-470
Author(s):  
Konstantin Pavlovskii ◽  
Natalia Ivanova
Keyword(s):  
Mass Transfer ◽  
Thermal Equilibrium ◽  
Current Theory ◽  
Theoretical Explanation ◽  
High Mass ◽  
High Luminosity ◽  
X Ray ◽  
Common Envelope ◽  
Long Period ◽  
X Ray Binaries

AbstractUltra-compact X-ray binaries (UCXBs) are accreting systems with periods less than 1 hour, which qualifies them to contain a degenerate donor-companion. One would expect such systems to have the easiest theoretical explanation, compared to other kinds of X-ray binaries. Nonetheless, current theory fails to explain high mass transfer (MT) rates in three recently well observed long-period UCXBs. We find that this range of MT rates can be maintained if the donor is a remnant of an out-of-thermal-equilibrium naked core of a giant which was revealed in a very recent episode of a common envelope (CE) event.

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