scholarly journals On one-parametric formula relating the frequencies of twin-peak quasi-periodic oscillations

2017 ◽  
Vol 473 (1) ◽  
pp. L136-L140 ◽  
Author(s):  
Gabriel Török ◽  
Kateřina Goluchová ◽  
Eva Šrámková ◽  
Jiří Horák ◽  
Pavel Bakala ◽  
...  
2016 ◽  
Vol 833 (2) ◽  
pp. 273 ◽  
Author(s):  
Gabriel Török ◽  
Kateřina Goluchová ◽  
Martin Urbanec ◽  
Eva Šrámková ◽  
Karel Adámek ◽  
...  

2012 ◽  
Vol 8 (S290) ◽  
pp. 319-320
Author(s):  
Gabriel Török ◽  
Pavel Bakala ◽  
Eva Šrámková ◽  
Zdeněk Stuchlík ◽  
Martin Urbanec ◽  
...  

AbstractWe consider twin-peak quasi-periodic oscillations (QPOs) observed in the accreting low-mass neutron star (NS) binaries and explore restrictions to NS properties that are implied by various QPO models. For each model and each source, the consideration results in a specific relation between the NS mass M and the angular-momentum j rather than in their single preferred combination. Furthermore, the inferred restrictions on NS properties (or QPO models) are weaker for the low-frequency sources than for the high-frequency sources.


2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Bo Gao ◽  
Xue-Mei Deng

AbstractWe investigate neutral and charged test particles’ motions around quantum-corrected Schwarzschild black holes immersed in an external magnetic field. Taking the innermost stable circular orbits of neutral timelike particles into account, we find that the black holes can mimic different ranges of the Kerr black hole’s spin |a/M| from 0.15 to 0.99. Our analysis of charged test particles’ motions suggests that the values of the angular momentum l and the energy $$E^{2}$$ E 2 are slightly higher than Schwarzschild black holes. The allowed regions of the $$(l,E^{2})$$ ( l , E 2 ) demonstrate that the critical energy $$E^{2}_{c}$$ E c 2 divides the charged test particle’s bounded trajectory into three types. With the help of a Monte Carlo method, we study the charged particles’ probabilities of falling into the black holes and find that the probability density function against l depends on the signs of the particles’ charges. Finally, the epicyclic frequencies of the charged particles are considered with respect to the observed twin peak quasi-periodic oscillations frequencies. Our results might provide hints for distinguishing quantum-corrected Schwarzschild black holes from Schwarzschild ones by using the dynamics of charged test particles around the strong gravitational field.


2015 ◽  
Vol 457 (1) ◽  
pp. L19-L23 ◽  
Author(s):  
G. Török ◽  
K. Goluchová ◽  
J. Horák ◽  
E. Šrámková ◽  
M. Urbanec ◽  
...  

2012 ◽  
Vol 8 (S291) ◽  
pp. 524-526
Author(s):  
Gabriel Török ◽  
Martin Urbanec ◽  
Kateřina Goluchová ◽  
Pavel Bakala ◽  
Eva Šrámková ◽  
...  

AbstractIn a series of works - Török et al. (2010, 2012a) and Urbanec et al. (2010a) - we explored restrictions to neutron star properties that are implied by various models of twin-peak quasi-periodic oscillations. Here we sketch an attempt to confront the obtained mass–angular-momentum relations and limits on neutron star compactness with the parameters estimated by assuming various equations of state and the spin frequency of the atoll source 4U 1636-53.


2015 ◽  
Vol 581 ◽  
pp. A35 ◽  
Author(s):  
P. Bakala ◽  
K. Goluchová ◽  
G. Török ◽  
E. Šrámková ◽  
M. A. Abramowicz ◽  
...  

2010 ◽  
Vol 714 (1) ◽  
pp. 748-757 ◽  
Author(s):  
Gabriel Török ◽  
Pavel Bakala ◽  
Eva Šrámková ◽  
Zdeněk Stuchlík ◽  
Martin Urbanec

2012 ◽  
Vol 8 (S290) ◽  
pp. 317-318
Author(s):  
Zdeněk Stuchlík ◽  
Andrea Kotrlová ◽  
Gabriel Török

AbstractWe present a Resonant Switch (RS) model of twin peak high-frequency quasi-periodic oscillations (HF QPOs), assuming switch of twin oscillations at a resonant point, where frequencies of the upper and lower oscillations νU and νL become to be commensurable and the twin oscillations change from one pair of the oscillating modes (corresponding to a specific model of HF QPOs) to some other pair due to non-linear resonant phenomena. The RS model enables to determine range of allowed values of spin a and mass M of the neutron star located at the atoll source 4U 1636-53 where two resonant points are observed at frequency ratios νU : νL = 3:2, 5:4.


2012 ◽  
Vol 760 (2) ◽  
pp. 138 ◽  
Author(s):  
Gabriel Török ◽  
Pavel Bakala ◽  
Eva Šrámková ◽  
Zdeněk Stuchlík ◽  
Martin Urbanec ◽  
...  

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