scholarly journals Discovery of a 34 Hz quasi-periodic oscillation in the X-ray emission of GRS 1915+105

2013 ◽  
Vol 432 (1) ◽  
pp. 19-22 ◽  
Author(s):  
T. M. Belloni ◽  
D. Altamirano
Keyword(s):  
Periodic Oscillation ◽  
Quasi Periodic Oscillation ◽  
X Ray

Discovery of an ∼7 H[CLC]z[/CLC] Quasi-periodic Oscillation in the Low-Luminosity Low-Mass X-Ray Binary 4U 1820−30

1999 ◽  
Vol 512 (1) ◽  
pp. L39-L42 ◽  
Author(s):  
Rudy Wijnands ◽  
Michiel van der Klis ◽  
Erik-Jan Rijkhorst
Keyword(s):  
Periodic Oscillation ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
Low Mass

The parallel tracks of kHz QPOs in low-mass X-ray binary 4U 1728−34: explorer of the bimodal accretion modes

2020 ◽  
Vol 497 (3) ◽  
pp. 2893-2898
Author(s):  
De-Hua Wang ◽  
Cheng-Min Zhang
Keyword(s):  
Neutron Star ◽  
Accretion Rate ◽  
Periodic Oscillation ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
Parallel Track ◽  
Theoretical Assumptions ◽  
Low Mass

ABSTRACT Parallel tracks in the relation between the lower kilohertz quasi-periodic oscillation (kHz QPO) frequency ν1 and the X-ray intensity I have been observed in the neutron star low-mass X-ray binary (NS-LMXB) 4U 1728−34, and we try to ascribe these phenomena to the bimodal accretion modes, i.e. the disc accretion and radial accretion. For the source with one constant radial accretion rate $\dot{M}_{\rm r}$, as the increase of the disc accretion rate $\dot{M}_{\rm d}$, the NS magnetosphere-disc radius can shrink from ∼18 to ∼16 km, while ν1 increases from ∼670 to ∼870 Hz. Then, due to the increase of the kHz QPO frequency and total X-ray intensity Itot, the source will trace out an oblique track in ν1–I relation. While, if the source enters another constant radial accretion rate due to the variation of the accretion environment, the increase of the disc accretion rate can arise another parallel track in ν1–I relation. Finally, the reliability of the theoretical assumptions, the variability of the accretion radius and accretion rate, as well as the dependence of the two accretion modes, are also investigated and discussed.

scholarly journals Possible ~1 hour quasi-periodic oscillation in narrow-line Seyfert 1 galaxy MCG–06–30–15

2018 ◽  
Vol 616 ◽  
pp. L6 ◽  
Author(s):  
Alok C. Gupta ◽  
Ashutosh Tripathi ◽  
Paul J. Wiita ◽  
Minfeng Gu ◽  
Cosimo Bambi ◽  
...  
Keyword(s):  
Light Curve ◽  
Energy Range ◽  
Periodic Oscillation ◽  
Light Curves ◽  
Narrow Line ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
S Period

We found a possible ~1 h quasi-periodic oscillation (QPO) in a ~55 ks X-ray observation of the narrow-line Seyfert 1 galaxy MCG–06–30–15 made with the XMM-Newton EPIC/pn detector in the energy range 0.3–10 keV. We identify a total modulation of ~16% in the light curve and find a ≃3670 s quasi-period using Lomb-Scargle periodogram (LSP) and weighted wavelet Z-transform (WWZ) techniques. Our analyses of eight light curves of MCG–06–30–15, indicated the possible presence of an oscillation during one of them. The LSP indicates a statistically significant (≃3σ) QPO detection. A WWZ analysis shows that the signal at this possible roughly 3670 s period is present, and rather persistent, throughout the observation; however, a signal around 8735 s is more persistent. We briefly discuss models that can produce X-ray QPOs with such periods in narrow line Seyfert 1 galaxies, as both other claimed QPO detections in this class of AGN had very similar periods.

ON THE HBO MECHANISM OF X-RAY NEUTRON STAR

2001 ◽  
Vol 10 (05) ◽  
pp. 625-632 ◽  
Author(s):  
C. M. ZHANG
Keyword(s):  
Neutron Star ◽  
Empirical Formula ◽  
Accretion Rate ◽  
Periodic Oscillation ◽  
Precession Frequency ◽  
Relativistic Motion ◽  
Quasi Periodic Oscillation ◽  
Motion Mechanism ◽  
X Ray ◽  
Proposed Model

We ascribe the 15–60 Hz Quasi Periodic Oscillation (QPO) to the periastron precession frequency of the orbiting accreted matter at the boundary of magnetosphere-disk of X-ray neutron star (NS). Considering the relativistic motion mechanism for the kHz QPO, that the radii of the inner disk and magnetosphere-disk of NS are correlated with each other by a factor is assumed. The obtained conclusions include: all QPO frequencies increase with increasing the accretion rate. The theoretical relations between 15–60 Hz QPO (HBO) frequency and the twin kHz QPOs are similar to the measured empirical formula. Further, the better fitted NS mass by the proposed model is about 1.9 solar masses for the detected LMXBs.

Sign in / Sign up

Export Citation Format

Share Document