On the Disappearance of Kilohertz Quasi-periodic Oscillations at a High Mass Accretion Rate in Low-Mass X-Ray Binaries

We ascribe the twin kilohertz Quasi Periodic Oscillations (kHz QPOs) of X-ray spectra of Low Mass X-Ray Binaries (LMXBs) to the pseudo-Newtonian Keplerian frequency and the apogee and perigee precession frequency of the same matter in the inner disk, and ascribe 15–60 Hz QPO (HBO) to the apogee (or perigee) precession and its second harmonic frequency to both apogee and perigee precession in the outer disk boundary of the neutron star (NS) magnetosphere. The radii of the inner and outer disks are correlated each other by a factor of two is assumed. The obtained conclusions include: all QPO frequencies increase and frequency difference of twin kHz QPOs decreases with increasing the accretion rate. The obtained theoretical relations between HBO frequency and twin kHz QPOs are simlilar to the measured empirical formula. Further, the theo-retical formula to calculate the NS mass by the twin kHz QPOs is proposed, and the resultant values are in the range of 1.4 to 1.8 M⊙. QPOs from LMXBs likely provide an accurate laboratory for a strong gravitational field, by which a new method to determine the NS masses of LMXBs is suggested.

Download Full-text

Quiescent luminosities of accreting neutron stars-possibility of neutrino losses due to strong pion condensations

International Journal of Modern Physics E ◽

10.1142/s0218301318500672 ◽

2018 ◽

Vol 27 (08) ◽

pp. 1850067 ◽

Cited By ~ 4

Author(s):

Yasuhide Matsuo ◽

HeLei Liu ◽

Masa-aki Hashimoto ◽

Tsuneo Noda

Keyword(s):

Neutron Star ◽

Neutron Stars ◽

Accretion Rate ◽

Cooling Process ◽

X Ray ◽

Mass Accretion Rate ◽

Star Models ◽

Low Mass ◽

X Ray Binaries

We construct the quiescent neutron star models in the evolutionary calculations. The X-ray luminosities have been derived in terms of the time-averaged mass accretion rate for various neutron star masses and surface compositions. We compare the quiescent luminosities observed from X-ray transients in low mass X-ray binaries, where the stellar evolutionary calculations of accreting neutron stars include neutrino cooling due to strong pion condensations. Our results based on the evolutionary calculations suggest that stronger cooling process would be necessary to be consistent with observations.

Download Full-text

QPOs in compact binaries from small scale eruptions in an inner magnetized disk

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3410 ◽

2020 ◽

Author(s):

Nicolas Scepi ◽

Mitchell C Begelman ◽

Jason Dexter

Keyword(s):

Rapid Heating ◽

Small Scale ◽

Type B ◽

Periodic Oscillations ◽

X Ray ◽

Compact Binaries ◽

Heating And Cooling ◽

Low Mass ◽

X Ray Binaries ◽

Standard Disk

Abstract Dwarf novæ (DNe) and low mass X-ray binaries (LMXBs) are compact binaries showing variability on time scales from years to less than seconds. Here, we focus on explaining part of the rapid fluctuations in DNe, following the framework of recent studies on the monthly eruptions of DNe that use a hybrid disk composed of an outer standard disk and an inner magnetized disk. We show that the ionization instability, that is responsible for the monthly eruptions of DNe, is also able to operate in the inner magnetized disk. Given the low density and the fast accretion time scale of the inner magnetized disk, the ionization instability generates small, rapid heating and cooling fronts propagating back and forth in the inner disk. This leads to quasi-periodic oscillations (QPOs) with a period of the order of 1000 s. A strong prediction of our model is that these QPOs can only develop in quiescence or at the beginning/end of an outburst. We propose that these rapid fluctuations might explain a subclass of already observed QPOs in DNe as well as a, still to observe, subclass of QPOs in LMXBs. We also extrapolate to the possibility that the radiation pressure instability might be related to Type B QPOs in LMXBs.

Download Full-text

The formation of high-mass black holes in low-mass X-ray binaries

New Astronomy ◽

10.1016/s1384-1076(99)00023-8 ◽

1999 ◽

Vol 4 (4) ◽

pp. 313-323 ◽

Cited By ~ 41

Author(s):

G.E. Brown ◽

C.-H. Lee ◽

Hans A. Bethe

Keyword(s):

Black Holes ◽

High Mass ◽

X Ray ◽

Low Mass ◽

X Ray Binaries

Download Full-text

A possible explanation of the parallel tracks in kilohertz quasi-periodic oscillations from low-mass-X-ray binaries

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/sty1191 ◽

2018 ◽

Cited By ~ 2

Author(s):

Chang-Sheng Shi ◽

Shuang-Nan Zhang ◽

Xiang-Dong Li

Keyword(s):

Periodic Oscillations ◽

X Ray ◽

Low Mass ◽

X Ray Binaries

Download Full-text

GRO J1744-28 and the Rapid Burster; Bizarre Objects!

Symposium - International Astronomical Union ◽

10.1017/s007418090011455x ◽

1998 ◽

Vol 188 ◽

pp. 111-111

Author(s):

Walter H.G. Lewin

Keyword(s):

Type Ii ◽

Time Intervals ◽

Periodic Oscillations ◽

X Ray ◽

Magnetic Dipole Field ◽

Order Of Magnitude ◽

Low Mass ◽

Type Ii Bursts ◽

The Difference ◽

X Ray Binaries

The bursts from GRO J1744-28 are due to accretion instabilities as is the case for type II bursts in the Rapid Burster. Both sources are transient Low-Mass X-ray Binaries, and they both exhibit unusual quasi-periodic-oscillations in their persistent X-ray flux following several (not all) of the type II bursts. There are important differences too. GRO J1744-28 is an X-ray pulsar; the Rapid Burster is not. In addition, the pattern of bursts and the burst peak luminosities are very different for the two sources. Time intervals between the rapidly repetitive bursts in the Rapid Burster can be as short as 10 sec, in 1744-28 they are as short as 200 sec. The peak luminosities of the bursts from GRO J1744-28 can exceed the Eddington luminosity (for assumed isotropic emission) by one to two orders of magnitude. The QPO centroid frequencies (see above) differ by an order of magnitude (~0.04 Hz for the Rapid Burster, and 0.3 Hz for GRO J1744-28). The difference in behavior p obably lies in the difference in the magnetic dipole field strength of the accreting neutron stars (for GRO J1744-28 it is almost certainly much higher than for the Rapid Burster). It remains puzzling, why GRO J1744-28 and the Rapid Burster are the only known sources which exhibit rapidly repetitive type II bursts.

Download Full-text

The Beat-Frequency Interpretation of Kilohertz Quasi-periodic Oscillations in Neutron Star Low-Mass X-Ray Binaries

The Astrophysical Journal ◽

10.1086/311455 ◽

1998 ◽

Vol 501 (1) ◽

pp. L95-L99 ◽

Cited By ~ 54

Author(s):

Dimitrios Psaltis ◽

Mariano Méndez ◽

Rudy Wijnands ◽

Jeroen Homan ◽

Peter G. Jonker ◽

...

Keyword(s):

Neutron Star ◽

Beat Frequency ◽

Periodic Oscillations ◽

X Ray ◽

Frequency Interpretation ◽

Low Mass ◽

X Ray Binaries

Download Full-text

Jets in the soft state in Cyg X-3 caused by advection of the donor magnetic field and unification with low-mass X-ray binaries

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3447 ◽

2019 ◽

Vol 492 (1) ◽

pp. 223-231 ◽

Cited By ~ 4

Author(s):

Xinwu Cao ◽

Andrzej A Zdziarski

Keyword(s):

Magnetic Field ◽

High Mass ◽

Vertical Magnetic Field ◽

Subsequent Formation ◽

X Ray ◽

Soft State ◽

Hard State ◽

Low Mass ◽

X Ray Binaries

ABSTRACT The high-mass accreting binary Cyg X-3 is distinctly different from low-mass X-ray binaries (LMXBs) in having powerful radio and γ-ray emitting jets in its soft spectral state. However, the transition from the hard state to the soft one is first associated with quenching of the hard-state radio emission, as in LMXBs. The powerful soft-state jets in Cyg X-3 form, on average, ∼50 d later. We interpret the initial jet quenching as due to the hard-state vertical magnetic field quickly diffusing away in the thin disc extending to the innermost stable circular orbit in the soft state, or, if that field is produced in situ, also cessation of its generation. The subsequent formation of the powerful jets occurs due to advection of the magnetic field from the donor. We find this happens only above certain threshold accretion rate associated with appearance of magnetically driven outflows. The ∼50 d lag is of the order of the viscous time-scale in the outer disc, while the field advection is much faster. This process does not happen in LMXBs due to the magnetic fluxes available from their donors being lower than that for the wind accretion from the Wolf–Rayet donor of Cyg X-3. In our model, the vertical magnetic field in the hard state, required to form the jets both in Cyg X-3 and LMXBs, is formed in situ rather than advected from the donor. Our results provide a unified scenario of the soft and hard states in both Cyg X-3 and LMXBs.

Download Full-text