Quasi-Periodic and Periodic Oscillations in the Dwarf Nova AH Her

With a high speed photometric system we have made extensive observation of the dwarf nova AH Her. We have detected rapid oscillations on two consecutive nights during the recovery portion of the light curve of a typical outburst during the spring of 1979. The periods and the sense of the change of period are consistent with previous observations of rapid oscillations of AH Her. On another occasion we detected quasi-periodic oscillations during the rising portion of an outburst. These are similar in appearance to quasi-periodic oscillations found in other cataclysmic variables in that they appear with high statistical significance in the autocorrelation function but are not apparent in power spectra (Robinson and Nather 1979). However they are different from those reported by Robinson and Nather in the sense that they have the same order of period as the periodic rapid oscillations typical of AH Her. These results will be presented together with a discussion of their Implications.

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Two-channel Photometry of Cataclysmic Variables

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000024255 ◽

1991 ◽

Vol 9 (2) ◽

pp. 302-303

Author(s):

Denis J. Sullivan

Keyword(s):

New Zealand ◽

Light Curve ◽

High Speed ◽

Cataclysmic Variables ◽

The Other ◽

Comparison Star ◽

Photometric System ◽

High Speed Photometry

AbstractHigh-speed photometry of two cataclysmic variables is presented. The observations were made using a two-channel photometric system and the Mt John 0.6 or 1-m telescopes at Lake Tekapo in New Zealand. Both objects have only recently been identified as cataclysmic variables. One of the objects is a high inclination system featuring a deep eclipse in the light curve and a 5.5 hour period, while the other object, despite being relatively faint, clearly exhibits a 2.5 hour period and out of eclipse variability. Simultaneous monitoring of a nearby comparison star for this latter object was particularly beneficial, even during good photometric conditions.

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Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables â VIII. VW Hyi in outburst observed with the Southern African Large Telescope

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2009.15666.x ◽

2010 ◽

Vol 401 (1) ◽

pp. 500-506 ◽

Cited By ~ 5

Author(s):

P. A. Woudt ◽

B. Warner ◽

D. O'Donoghue ◽

D. A. H. Buckley ◽

M. Still ◽

...

Keyword(s):

Cataclysmic Variables ◽

Large Telescope ◽

Periodic Oscillations ◽

Dwarf Nova

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High Speed UV Photometry of the AM Her Systems AM Her, VV Pup And V834 Cen, with the Hubble Space Telescope

International Astronomical Union Colloquium ◽

10.1017/s0252921100038719 ◽

1996 ◽

Vol 158 ◽

pp. 223-224

Author(s):

K. Schaefer ◽

H. Bond ◽

G. Chanmugam

Keyword(s):

Preliminary Analysis ◽

High Speed ◽

Hubble Space Telescope ◽

Cataclysmic Variables ◽

Low Frequency ◽

Gabor Transform ◽

Periodic Oscillations ◽

Space Telescope ◽

Uv Photometry ◽

Magnetic Cataclysmic Variables

We have used the High Speed Photometer (HSP) aboard the Hubble Space Telescope to observe the magnetic cataclysmic variables VV Pup, AM Her, and V834 Cen in the UV (1400…3300 Å) with 0.01 s time resolution. We detected low frequency flickering in all three systems, and compare the time-scales with the predictions of King (1989). At higher frequencies we searched for shock oscillations from the accretion column(s) in these systems. The data were analyzed using the Gabor transform wavelet-like technique (Heil & Walnut 1989) to search for frequency evolution throughout each observation. Preliminary analysis suggests the detection of rapid UV quasi-periodic oscillations (QPOs) in VV Pup at 0.74 Hz, and at 4.4 Hz in V834 Cen. As in ground based observations, our observations failed to yield any rapid QPOs in AM Her itself.

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Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables - II. A low-inertia magnetic accretor model

Monthly Notices of the Royal Astronomical Society ◽

10.1046/j.1365-8711.2002.05596.x ◽

2002 ◽

Vol 335 (1) ◽

pp. 84-98 ◽

Cited By ~ 69

Author(s):

Brian Warner ◽

Patrick A. Woudt

Keyword(s):

Cataclysmic Variables ◽

Periodic Oscillations ◽

Dwarf Nova

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Probing the X-ray Variability of X-ray Binaries

Symposium - International Astronomical Union ◽

10.1017/s0074180900194483 ◽

2003 ◽

Vol 214 ◽

pp. 236-239

Author(s):

Wenfei Yu

Keyword(s):

Neutron Star ◽

Light Curve ◽

Time Scale ◽

Accretion Rate ◽

Power Spectra ◽

The Other ◽

Periodic Oscillations ◽

X Ray ◽

Orbital Frequency ◽

X Ray Binaries

Kilohertz quasi-periodic oscillations (kHz QPOs) has been regarded as representing the Keplerian frequency at the inner disk edge in the neutron star X-ray binaries. The so-called “parallel tracks” on the plot of the kHz QPO frequency vs. X-ray flux in neutron star X-ray binaries, on the other hand, show the correlation between the kHz QPO frequency and the X-ray flux on time scales from hours to days. This is suspected as caused by the variations of the mass accretion rate through the accretion disk surrounding the neutron star. We show here that by comparing the correlation between the kHz QPO frequency and the X-ray count rate on a certain QPO time scale observed approximately simultaneous in the Fourier power spectra of the X-ray light curve, we have found evidences that the X-ray flux of millihertz QPOs in neutron star X-ray binaries is generated inside the inner disk edge if adopting that the kilohertz QPO frequency is an orbital frequency at the inner disk edge.

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