scholarly journals Spectral observations of X Persei: Connection between Hα and X-ray emission

2019 ◽  
Vol 622 ◽  
pp. A173 ◽  
Author(s):  
R. Zamanov ◽  
K. A. Stoyanov ◽  
U. Wolter ◽  
D. Marchev ◽  
N. I. Petrov
Keyword(s):  
Neutron Star ◽  
Emission Line ◽  
Equivalent Width ◽  
Roche Lobe ◽  
Published Data ◽  
Expansion Velocity ◽  
X Ray ◽  
Spectroscopic Observations ◽  
Show Evidence ◽  
Disc Size

We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period 1999–2018. Using new and published data, we found that during “disc-rise” the expansion velocity of the circumstellar disc is 0.4–0.7 km s−1. Our results suggest that the disc radius in recent decades show evidence of resonant truncation of the disc by resonances 10:1, 3:1, and 2:1, while the maximum disc size is larger than the Roche lobe of the primary and smaller than the closest approach of the neutron star. We find correlation between equivalent width of Hα emission line (Wα) and the X-ray flux, which is visible when 15 Å < Wα ≤ 40 Å. The correlation is probably due to wind Roche lobe overflow.

scholarly journals SALT observations of the supernova remnant MCSNR J0127−7332 and its associated Be X-ray binary SXP 1062 in the SMC

2021 ◽  
Vol 503 (3) ◽  
pp. 3856-3866
Author(s):  
V V Gvaramadze ◽  
A Y Kniazev ◽  
J S Gallagher ◽  
L M Oskinova ◽  
Y-H Chu ◽  
...  
Keyword(s):  
Neutron Star ◽  
Emission Line ◽  
Supernova Remnant ◽  
Supernova Explosion ◽  
High Mass ◽  
Expansion Velocity ◽  
X Ray ◽  
Orbital Phase ◽  
Be Star ◽  
The Moment

ABSTRACT We report the results of optical spectroscopy of the Small Magellanic Cloud supernova remnant (SNR) MCSNR J0127−7332 and the mass donor Be star, 2dFS 3831, in its associated high-mass X-ray binary SXP 1062 carried out with the Southern African Large Telescope. Using high-resolution long-slit spectra, we measured the expansion velocity of the SNR shell of ${\approx} 140 \, {\rm \, km\, s^{-1}}$, indicating that MCSNR J0127−7332 is in the radiative phase. We found that the observed line ratios in the SNR spectrum can be understood if the local interstellar medium is ionized by 2dFS 3831 and/or OB stars around the SNR. We propose that MCSNR J0127−7332 is the result of supernova explosion within a bubble produced by the stellar wind of the supernova progenitor and that the bubble was surrounded by a massive shell at the moment of supernova explosion. We estimated the age of MCSNR J0127−7332 to be ${\lesssim} 10\, 000$ yr. We found that the spectrum of 2dFS 3831 changes with orbital phase. Namely, the equivalent width of the H α emission line decreased by ≈40 per cent in ≈130 d after periastron passage of the neutron star and then almost returned to its original value in the next ≈100 d. Also, the spectrum of 2dFS 3831 obtained closest to the periastron epoch (about 3 weeks after the periastron) shows a noticeable emission line of He ii λ4686, which disappeared in the next 2 weeks. We interpret these changes as a result of the temporary perturbation and heating of the disc as the neutron star passes through it.

scholarly journals X-ray variability of the HMXB Cen X-3: evidence for inhomogeneous accretion flows.

2020 ◽  
Author(s):  
G Sanjurjo-Ferrín ◽  
J M Torrejón ◽  
K Postnov ◽  
L Oskinova ◽  
J J Rodes-Roca ◽  
...  
Keyword(s):  
Equivalent Width ◽  
Compact Star ◽  
Timing Analysis ◽  
Roche Lobe ◽  
The Other ◽  
Emission Lines ◽  
High Mass ◽  
X Ray ◽  
Accretion Flows ◽  
Inner Radius

Abstract Cen X-3 is a compact high mass X-ray binary likely powered by Roche lobe overflow. We present a phase-resolved X-ray spectral and timing analysis of two pointed XMM-Newton observations. The first one took place during a normal state of the source, when it has a luminosity LX ∼ 1036 erg s−1. This observation covered orbital phases φ = 0.00 − 0.37, i.e. the egress from the eclipse. The egress lightcurve is highly structured, showing distinctive intervals. We argue that different intervals correspond to the emergence of different emitting structures. The lightcurve analysis enables us to estimate the size of such structures around the compact star, the most conspicuous of which has a size ∼0.3R*, of the order of the Roche lobe radius. During the egress, the equivalent width of Fe emission lines, from highly ionized species, decreases as the X-ray continuum grows. On the other hand, the equivalent width of the Fe Kα line, from near neutral Fe, strengthens. This line is likely formed due to the X-ray illumination of the accretion stream. The second observation was taken when the source was 10 times X-ray brighter and covered the orbital phases φ = 0.36 − 0.80. The X-ray lightcurve in the high state shows dips. These dips are not caused by absorption but can be due to instabilities in the accretion stream. The typical dip duration, of about 1000 s, is much longer than the timescale attributed to the accretion of the clumpy stellar wind of the massive donor star, but is similar to the viscous timescale at the inner radius of the accretion disk.

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 Models for Compact Pulsing X-Ray Sources

1973 ◽  
Vol 55 ◽  
pp. 143-154 ◽  
Author(s):  
Jeremiah P. Ostriker ◽  
Kris Davidson
Keyword(s):  
Neutron Star ◽  
Rotation Period ◽  
Critical Value ◽  
Blackbody Radiation ◽  
Roche Lobe ◽  
Magnetic Pole ◽  
Solar Mass ◽  
Centrifugal Barrier ◽  
Companion Star ◽  
X Ray

Cen X-3 is probably a neutron star, releasing the infall energy of accreted matter. Sufficient material for accretion will be provided by a conventional stellar wind from its more massive companion star. That star is not likely to rotate synchronously; therefore a ‘Roche lobe’ analysis of the eclipses is not valid. A ‘tidal lobe’ analysis allows the neutron star to have a mass of the order of one solar mass. Overflow of the ‘Roche lobe’ is neither necessary as a source of mass nor probable in view of the observed stellar line widths of the two identified X-ray companions.The mass flow onto the condensed star is very small in all cases. It is limited, for an object of m solar masses by the Eddington Limiting Luminosity to Ṁac < 10–7.4m(M⊙ yr−1), which limit applies even if the accreting object contacts or traverses its companion star.The observed 4.84 s rotation period of the Cen X-3 neutron star is very simply explained as the critical value where a centrifugal barrier regulates the rate of infall to the surface. The X-ray spectrum is understood as blackbody radiation coming from a well-defined area near each magnetic pole of the neutron star.

scholarly journals X-ray selected Wolf-Rayet stars: The discovery of Th35-42 and prospects for future X-ray surveys

1995 ◽  
Vol 163 ◽  
pp. 481-485
Author(s):  
S. Mereghetti ◽  
T. Belloni ◽  
F. Haberl ◽  
W. Voges
Keyword(s):  
Neutron Star ◽  
Emission Line ◽  
Optical Spectroscopy ◽  
Early Type ◽  
X Ray ◽  
Sky Survey ◽  
Colliding Winds ◽  
Einstein Observatory

The X-ray source 1E 1024.0-5732, serendipitously discovered with the Einstein Observatory, was previously interpreted as a rapidly spinning neutron star, accreting matter from its massive early-type companion, the emission-line star Th35-42. However, new ROSAT data do not support the presence of a neutron star in this source. A more likely scenario, also indicated by recent optical spectroscopy, involves X-ray emission from the colliding winds of a WR+O binary. Surprisingly, this star remained unnoticed during an extensive optical search for new Wolf-Rayet stars, carried out in this region of sky. Stimulated by the discovery of this first X-ray selected WR star, we have undertaken a search for similar objects in the data from the ROSAT All Sky Survey.

scholarly journals A relativistic iron emission line from the neutron star low-mass X-ray binary GX 3+1

2012 ◽  
Vol 542 ◽  
pp. L27 ◽  
Author(s):  
S. Piraino ◽  
A. Santangelo ◽  
P. Kaaret ◽  
B. Mück ◽  
A. D’Aì ◽  
...  
Keyword(s):  
Neutron Star ◽  
Emission Line ◽  
X Ray ◽  
Low Mass

scholarly journals Merging of Iron Lines in Spectra of X-ray Burst Sources

1990 ◽  
Vol 115 ◽  
pp. 85-89
Author(s):  
J. Madej
Keyword(s):  
Neutron Star ◽  
Energy Range ◽  
Effective Temperature ◽  
Equivalent Width ◽  
Single Line ◽  
Spectral Features ◽  
X Ray ◽  
Synthetic Spectra

AbstractModel atmospheres and synthetic spectra of neutron star of the effective temperature 107 K are presented. All the iron spectral features in the energy range 6-10 keV (uncorrected for redshift) are washed out by instrumental or intrinsic broadening, which leaves only a single line of the equivalent width comparable with the observations.

scholarly journals Recent Spectroscopy of X-Ray Sources and Systems Related to Cataclysmic Variables: I

1983 ◽  
Vol 72 ◽  
pp. 21-24
Author(s):  
A.P. Cowley ◽  
D. Crampton ◽  
J.B. Hutchings
Keyword(s):  
Emission Line ◽  
Time Scale ◽  
Cataclysmic Variables ◽  
Short Time Scale ◽  
X Ray ◽  
Spectroscopic Observations ◽  
Low Mass ◽  
Short Time

ABSTRACTWe present results of recent spectroscopic observations of A) some LMC X-ray sources, B) the X-ray burster 1735-44, and C) the peculiar emission-line binary BE UMa. From the short time scale variations and inferred low mass components each shows some similarities to more classical CV's.

scholarly journals A Millisecond Pulsar Progenitor to an Ultra-Compact Low-Mass X-ray Binary

1996 ◽  
Vol 160 ◽  
pp. 521-522
Author(s):  
S. C. Lundgren ◽  
E. Ergma ◽  
J. M. Cordes
Keyword(s):  
Neutron Star ◽  
Gravitational Radiation ◽  
Roche Lobe ◽  
Millisecond Pulsar ◽  
X Ray ◽  
Binary Neutron Star ◽  
Star Evolution ◽  
Orbital Decay ◽  
Low Mass ◽  
Ultimate Fate

AbstractWe discuss a twist in binary neutron star evolution scenarios in which a millisecond pulsar system is actually aprogenitorfor a low-mass X-ray binary system. After 7 billion years of orbital decay due to gravitational radiation, the millisecond pulsar PSR J0751+1807 will enter a low-mass X-ray binary phase. When the orbital period reaches about 5 minutes, the white dwarf will overflow its Roche lobe, transferring mass to the neutron star. Its predicted observational X-ray parameters are very similar to the ultra-compact low-mass X-ray binary 1820–303. The ultimate fate of the system after Roche-lobe overflow is unknown. One possibility is that the companion may eventually tidally disrupt, leaving a disk of material which could form into planets.

Detection of the progenitors of Be X-ray Binaries

2018 ◽  
Vol 14 (S346) ◽  
pp. 143-145 ◽  
Author(s):  
Douglas Gies ◽  
Luqian Wang ◽  
Geraldine Peters
Keyword(s):  
Neutron Star ◽  
Emission Line ◽  
Recent Survey ◽  
X Ray ◽  
Ultraviolet Spectra ◽  
The Future ◽  
Far Ultraviolet ◽  
X Ray Binaries

AbstractA recent survey of the far-ultraviolet spectra of 264 B-emission line stars has revealed 16 systems with hot companions that are the stripped down remains of a former mass donor star. Some of these will probably become Be + neutron star X-ray binaries in the future. The actual numbers of such systems may be large, because the detected systems have companions that occupy the brief and bright, He-shell burning stage of evolution.

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