The correlations and anticorrelations in QPO data

Abstract

Double peak kHz QPO frequencies in neutron star sources varies in time by a factor of hundreds Hz while in microquasar sources the frequencies are fixed and located at the line ν_2 = 1.5 ν_1 in the frequency-frequency plot. The crucial question in the theory of twin HFQPOs is whether or not those observed in neutron-star systems are essentially different from those observed in black holes. In black hole systems the twin HFQPOs are known to be in a 3:2 ratio for each source. At first sight, this seems not to be the case for neutron stars. For each individual neutron star, the upper and lower kHz QPO frequencies, ν_2 and ν_1, are linearly correlated, ν_2=A ν_1 + B, with the slope A < 1.5, i.e., the frequencies definitely are not in a 1.5 ratio. In this contribution we show that when considered jointly on a frequency-frequency plot, the data for the twin kHz QPO frequencies in several (as opposed to one) neutron stars uniquely pick out a certain preferred frequency ratio that is equal to 1.5 for the six sources examined so far.

3 pages, 1 figure, Astronomische Nachrichten, in press

References in corpus (3)

• Evidence for a 2:3 resonance in Sco X-1 kHz QPOs
• An abrupt drop in the coherence of the lower kilohertz QPO in 4U 1636-536
• The distribution of kHz QPO frequencies in bright LMXBs

Cited by in corpus (15)

• Multi-resonance orbital model of high-frequency quasi-periodic oscillations: possible high-precision determination of black hole and neutron star spin
• Orbital resonances in discs around braneworld Kerr black holes
• Quasiperiodic oscillations in a strong gravitational field around neutron stars testing braneworld models
• Resonant radii of kHz quasi-periodic oscillations in Keplerian discs orbiting neutron stars
• Supporting evidence for the signature of the innermost stable circular orbit in Rossi X-ray data from 4U1636-536
• Twin peak quasi-periodic oscillations as signature of oscillating cusp torus
• Timescale of twin-peak quasi-periodic oscillations and mass of accreting neutron stars
• Mass-angular-momentum relations implied by models of twin peak quasi-periodic oscillations
• Disc-oscillation resonance and neutron star QPOs: 3:2 epicyclic orbital model
• Simple analytic formula relating the mass and spin of accreting compact objects to their rapid X-ray variability
• Correlations between the frequencies of twin kHz QPOs and spins of neutron stars in LMXBs
• On one-parametric formula relating the frequencies of twin-peak quasi-periodic oscillations
• Correlation between 3:2 QPO pairs and Jets in Black Hole X-ray Binaries
• Constraining the mass and moment of inertia of neutron stars from quasi-periodic oscillations in X-ray binaries
• Quasi-periodic oscillatory motion of particles orbiting a distorted deformed compact object