The correlations and anticorrelations in QPO data
- 24 October 2005
- journal article
- research article
- Published by Wiley in Astronomische Nachrichten
- Vol. 326 (9) , 864-866
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 = 1.5ν 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 = Aν 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.Keywords
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This publication has 3 references indexed in Scilit:
- An abrupt drop in the coherence of the lower kHz quasi-periodic oscillations in 4U 1636−536Monthly Notices of the Royal Astronomical Society, 2005
- The distribution of kHz QPO frequencies in bright low mass X-ray binariesAstronomy & Astrophysics, 2005
- Evidence for a 2:3 resonance in Sco X-1 kHz QPOsAstronomy & Astrophysics, 2003