In 2014, Dheeraj Pasham (NASA Goddard) and colleagues weighed a potential IMBH using quasi-periodic oscillations
(QPOs), cyclic blips in a black hole's X-ray signal that astronomers suspect are related to the object's mass.
Twenty years after the discovery of neutron stars, quasi-periodic oscillations (QPOs) of X-rays were observed first from white dwarfs and then from neutron stars [13-14].
Intensity-dependent quasi-periodic oscillations in the X-ray flux of GX5-1.
This proposal aims to connect contemporary accretion and jet theory with observations of powerful outflows and quasi-periodic oscillations
in accreting black hole systems.
Lin YF, Boutelier M, Barret D, Zhang SN (2011) Studying Frequency Relationships of Kilohertz Quasi-periodic Oscillations
for 4U 163653 and Sco X-1: Observations Confront Theories.
From May 28 to June 2, the system's X-ray and radio emissions were fairly steady, although RXTE data show that cyclic X-ray variations, known as quasi-periodic oscillations
or QPOs, gradually increased in frequency over the same period.
Interestingly, when eigen values occur in pairs (nearly equal values), they are indicative of quasi-periodic oscillations
present in the original time series.
Astronomers call these rhythmic pulses quasi-periodic oscillations
, or QPOs.
These signals, called quasi-periodic oscillations
(QPOs), are semi-regular beats that sometimes appear in the X-ray emission from black holes and neutron stars when they're furiously accreting material.
From the figures we observe a quasi-periodic oscillations
in the conductance (Fig.
Israel (Rome Astronomical Observatory, Italy) discovered quasi-periodic oscillations
(QPOs) in the fading emission of the December 27, 2004, giant flare ("quasi-periodic" means that the vibrations have a narrow range of frequencies centered on one frequency).
A more abstruse mass estimate is possible for rapidly rotating X-ray pulsars, some of which display quasi-periodic oscillations
with time scales of 3 milliseconds and less.