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In this paper we present high time-resolution observations of GW Librae and SDSS J161033.64-010223.3 -- two cataclysmic variables which have shown periodic variations attributed to non-radial pulsations of the white dwarf. We observed both…

Accreting white dwarfs in binary systems known as cataclysmic variables (CVs) have in recent years been shown to produce radio flares during outbursts, qualitatively similar to those observed from neutron star and black hole X-ray binaries,…

High Energy Astrophysical Phenomena · Physics 2019-10-09 Rob Fender , Joe Bright , Kunal Mooley , James Miller-Jones

How are accretion discs affected by their outflows? To address this question for white dwarfs accreting from cool giants, we performed optical, radio, X-ray, and ultraviolet observations of the outflow-driving symbiotic star MWC 560 (=V694…

ER Ursae Majoris is the prototype for a subset of SU UMa-type dwarf novae characterized by short cycle times between outburst, high outburst frequency, and ``negative'' superhumps. It suffers superoutbursts every 43 days, lasting 20 days,…

Solar and Stellar Astrophysics · Physics 2019-08-14 Giannina Guzman , Edward Sion , Patrick Godon

We present ASCA observations of the dwarf nova Z Camelopardalis during outburst and during a transition from quiescence to another outburst. At the beginning of the transition the X-ray count rate was an order of magnitude higher and the…

Astrophysics · Physics 2009-11-07 D. S. Baskill , P. J. Wheatley , J. P. Osborne

We combine AAVSO and VSS/RASNZ optical and Extreme Ultraviolet Explorer EUV light curves of dwarf novae in outburst to place constraints on the nature of dwarf nova outbursts. From the observed optical-EUV time delays of 0.75-1.5 days, we…

Astrophysics · Physics 2007-05-23 Christopher W. Mauche , Janet A. Mattei , Frank M. Bateson

We report on simultaneous $g'$, $R_{\rm c}$ and $I_{\rm c}$ photometry of SU Ursae Majoris during 2011 December - 2012 February using OAO/MITSuME. Our photometry revealed that quiescence is divided into three types based on the magnitude…

The time dependent evolution of the accretion disk around black hole is computed. The classical description of the $\alpha$-viscosity is adopted so the evolution is driven by the instability operating in the innermost radiation-pressure…

Astrophysics · Physics 2009-11-07 Agnieszka Janiuk , Bozena Czerny , Aneta Siemiginowska

Swift intensive accretion disk reverberation mapping of four AGN yielded light curves sampled $\sim$200-350 times in 0.3-10 keV X-ray and six UV/optical bands. Uniform reduction and cross-correlation analysis of these datasets yields three…

The properties of the aperiodic brightness variability for the dwarf nova HL CMa are considered. The variability of the system HL CMa is shown to be suppressed at frequencies above $7\times10^{-3}$Hz. Different variability suppression…

High Energy Astrophysical Phenomena · Physics 2016-10-05 Andrey Semena , Mikhail Revnivtsev , David Buckley , Alexander Lutovinov , Hannes Breytenbach

We present an analysis of CCD photometric observations of the eclipsing novalike cataclysmic variable DW UMa obtained in two different luminosity states: high and intermediate. The star presents eclipses with very different depth: ~1.2 mag…

Astrophysics · Physics 2009-11-10 V. Stanishev , Z. Kraicheva , H. M. J. Boffin , V. Genkov , C. Papadaki , S. Carpano

[Abridged] We present more than 4 years of Swift X-ray observations of the 2013 superoutburst, subsequent decline and quiescence of the WZ Sge-type dwarf nova SSS J122221.7-311525 (SSS122222) from 6 days after discovery. Only a handful of…

High Energy Astrophysical Phenomena · Physics 2018-03-14 V. V. Neustroev , K. L. Page , E. Kuulkers , J. P. Osborne , A. P. Beardmore , C. Knigge , T. Marsh , V. F. Suleimanov , S. V. Zharikov

During re-processing and analysis of the entire ROSAT Wide Field Camera (WFC) pointed observations database, we discovered a serendipitous, off-axis detection of the cataclysmic variable SW UMa at the onset of its 1997 October…

Astrophysics · Physics 2009-11-06 M. R. Burleigh , J. P. Pye , S. W. Poulton , K. B. Sohl , P. J. Wheatley , G. A. Wynn

We present a model of the non-stationary $\alpha$-disk with account for the irradiation and the vertical convection in the outer accretion disk where hydrogen is partially ionized. We include the viscous energy generation in the mix-length…

High Energy Astrophysical Phenomena · Physics 2015-12-03 Konstantin Malanchev , Nikolai Shakura

Very faint X-ray binaries appear to be transient in many cases with peak luminosities much fainter than that of usual soft X-ray transients, but their nature still remains elusive. We investigate the possibility that this transient…

High Energy Astrophysical Phenomena · Physics 2016-10-19 J. -M. Hameury , J. -P. Lasota

In this paper we report the discovery of a high energy component of the X-ray spectra of U Gem, which can be observed while the source is in outburst. We used Chandra and XMM-Newton observations to compare the quiescence and outburst X-ray…

Astrophysics · Physics 2009-11-11 T. Guver , C. Uluyazi , M. T. Ozkan , E. Gogus

We discuss the possibility of observing the transient formation event of an accretion disk from the tidal destruction process of an asteroid near a white dwarf (WD). This scenario is commonly proposed as the explanation for dusty disks…

Solar and Stellar Astrophysics · Physics 2015-06-04 Ealeal Bear , Noam Soker

The disc instability model which is supposed to describe outbursts of dwarf nova and low-mass X-ray binary transient systems is presented and reviewed in detail. Various deficiencies of the model are pointed out and various remedies and…

Astrophysics · Physics 2009-11-06 Jean-Pierre Lasota

We present the complete set of thirty four ASCA observations of non-magnetic cataclysmic variables. Timing analysis reveals large X-ray flux variations in dwarf novae in outburst (Z Cam, SS Cyg and SU UMa) and orbital modulation in high…

Astrophysics · Physics 2009-11-10 Darren S. Baskill , Peter J. Wheatley , Julian P. Osborne

We examine a new paradigm to account for the exponential decay seen in the light curves of some of the bright X-ray novae. These systems show an exponential decay in soft X-rays with an e-folding time constant of ~30 d. We investigate a…

Astrophysics · Physics 2009-10-31 J. K. Cannizzo