Time-scale of twin-peak quasi-periodic oscillations and mass of accreting neutron stars

@article{37782,
   author = {Török, Gabriel and Goluchová, Kateřina and Šrámková, Eva and Urbanec, Martin and Straub, Odele},
   article_number = {3},
   doi = {http://dx.doi.org/10.1093/mnras/stz1929},
   keywords = {accretion: accretion discs; stars: neutron; X-rays: binaries},
   language = {eng},
   issn = {0035-8711},
   journal = {Monthly Notices of the Royal Astronomical Society},
   title = {Time-scale of twin-peak quasi-periodic oscillations and mass of accreting neutron stars},
   url = {https://academic.oup.com/mnras/article-abstract/488/3/3896/5531771?redirectedFrom=fulltext},
   volume = {488},
   year = {2019}
}

TY  - JOUR
ID  - 37782
AU  - Török, Gabriel - Goluchová, Kateřina - Šrámková, Eva - Urbanec, Martin - Straub, Odele
PY  - 2019
TI  - Time-scale of twin-peak quasi-periodic oscillations and mass of accreting neutron stars
JF  - Monthly Notices of the Royal Astronomical Society
VL  - 488
IS  - 3
SP  - 3896-3903
EP  - 3896-3903
SN  - 00358711
KW  - accretion: accretion discs
KW  - stars: neutron
KW  - X-rays: binaries
UR  - https://academic.oup.com/mnras/article-abstract/488/3/3896/5531771?redirectedFrom=fulltext
L2  - https://academic.oup.com/mnras/article-abstract/488/3/3896/5531771?redirectedFrom=fulltext
N2  - Einstein’s general relativity predicts that orbital motion of accreted gas approaching a neutron star (NS) in a NS low-mass X-ray binary (LMXB) system occurs on a time-scale proportional to the NS mass. Radiation of the gas accounts for most of the observed LMXBs variability. In more than a dozen of sources twin-peak quasi-periodic oscillations (QPOs) have been observed. Inspired by the expected proportionality between periods of orbital motion and NS mass we present a straightforward comparison among these sources. We investigate relations between QPO periods and their ratios and identify characteristic time-scales of QPOs associated with individual sources. These time-scales are likely determined by the relative mass of each NS. We show that the characteristic time-scale of the millisecond pulsar XTE J1807.4-294 is longer than for most other NS LMXBs. Consequently, models of QPOs that consider geodesic orbital frequencies imply that the X-ray pulsars’ mass has to be about 50 per cent higher than the average mass of other sources, Consideration of other X-ray pulsars indicates that the exceptionality of XTE J1807.4-294 cannot be related to NS magnetic field in any simple manner. We suggest that QPOs observed in this source can help to discriminate between the proposed versions of the NS equation of state.
ER  - 

TÖRÖK, Gabriel, Kateřina GOLUCHOVÁ, Eva ŠRÁMKOVÁ, Martin URBANEC a Odele STRAUB. Time-scale of twin-peak quasi-periodic oscillations and mass of accreting neutron stars. \textit{Monthly Notices of the Royal Astronomical Society}. 2019, roč.~488, č.~3, s.~3896-3903. ISSN~0035-8711. Dostupné z: https://dx.doi.org/10.1093/mnras/stz1929.