<i>SWIFT</i>X-RAY TELESCOPE OBSERVATIONS OF THE NOVA-LIKE CATACLYSMIC VARIABLES MV Lyr, BZ Cam, AND V592 Cas

Balman, Ş.; Godon, Patrick; Sion, E. M.

doi:10.1088/0004-637x/794/1/84

Cited by 28 publications

(73 citation statements)

References 100 publications

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“…(consistently with Balman et al 2014) which reduces to 3.6 × 10 31 erg s −1 in the low state. Figure 1.…”

Section: Introductionsupporting

confidence: 53%

“…Part of the X-ray flux is probably generated in a wind from the system (Balman et al 2014, Zemko et al 2014). This may seem like a contradicting scenario to the one presented in this paper, but in fact it is not.…”

Section: Comparison With Past Interpretationsmentioning

confidence: 99%

“…The 0.2-10 keV flux of 5.4 × 10 −12 erg s −1 cm −2 corresponds to a luminosity of 1.7 × 10 32 erg s −1 . Using ROSAT data, Balman et al (2014) derived a 2σ upper limit to the soft black-body component (if any) associated to the boundary layer finding kT < 6.6 eV. Taking the accretion rates derived by optical and UV bands, the standard disc models predict an optically thick boundary layer with temperature (13 -33 eV) larger than that derived from the ROSAT data and luminosity (> 10 34 erg s −1 ) much higher than that inferred by using the Swift data.…”

Section: Introductionmentioning

confidence: 99%

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XMM–Newton observation of MV Lyr and the sandwiched model confirmation

Dobrotka

Ness

Mineshige

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present spectral and timing analyses of simultaneous X-ray and UV observations of the VY Scl system MV Lyr taken by XMM-Newton, containing the longest continuous X-ray+UV light curve and highest signal-to-noise X-ray (EPIC) spectrum to date. The RGS spectrum displays emission lines plus continuum, confirming model approaches to be based on thermal plasma models. We test the sandwiched model based on fast variability that predicts a geometrically thick corona that surrounds an inner geometrically thin disc. The EPIC spectra are consistent with either a cooling flow model or a 2-T collisional plasma plus Fe emission lines in which the hotter component may be partially absorbed which would then originate in a central corona or a partially obscured boundary layer, respectively. The cooling flow model yields a lower mass accretion rate than expected during the bright state, suggesting an evaporated plasma with a low density, thus consistent with a corona. Timing analysis confirms the presence of a dominant break frequency around log(f /Hz) = -3 in the X-ray Power Density Spectrum (PDS) as in the optical PDS. The complex soft/hard X-ray light curve behaviour is consistent with a region close to the white dwarf where the hot component is generated. The soft component can be connected to an extended region. We find another break frequency around log(f /Hz) = -3.4 that is also detected by Kepler. We compared flares at different wavelengths and found that the peaks are simultaneous but the rise to maximum is delayed in X-rays with respect to UV.

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“…(consistently with Balman et al 2014) which reduces to 3.6 × 10 31 erg s −1 in the low state. Figure 1.…”

Section: Introductionsupporting

confidence: 53%

Section: Comparison With Past Interpretationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

XMM–Newton observation of MV Lyr and the sandwiched model confirmation

Dobrotka

Ness

Mineshige

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Extending the result of Mauche & Mukai (2002), Zemko et al (2014) found that Swift X-ray spectral fits are clearly consistent with a collisionally ionised optically thin plasma, rather than a blackbody, when considering four VY Scl stars observed in both high and low optical states. Balman et al (2014) analysed X-ray datasets for two VY Scl systems, some of which were also used by Zemko et al (2014), and a novalike CV in their optical high-state, again finding that optically thin plasma emission provided the best fit. Our results presented here for V751 Cyg are in agreement with the 21st century findings for other VY Scl stars: there is no sign of blackbody emission in the XMM-Newton and Swift observations of V751 Cyg, at least in the high optical state.…”

Section: Discussionmentioning

confidence: 99%

X-ray and UV observations of V751 Cygni in an optical high state

Page

Osborne

Beardmore

et al. 2014

A&A

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Aims. The VY Scl system (anti-dwarf nova) V751 Cyg is examined following a claim of a super-soft spectrum in the optical low state. Methods. A serendipitous XMM-Newton X-ray observation and, 21 months later, Swift X-ray and UV observations, have provided the best such data on this source so far. These optical high-state datasets are used to study the flux and spectral variability of V751 Cyg.Results. Both the XMM-Newton and Swift data show evidence for modulation of the X-rays for the first time at the known 3.467 h orbital period of V751 Cyg. In two Swift observations, taken ten days apart, the mean X-ray flux remained unchanged, while the UV source brightened by half a magnitude. The X-ray spectrum was not super-soft during the optical high state, but rather due to multi-temperature optically thin emission, with significant (10 21−22 cm −2 ) absorption, which was higher in the observation by Swift than that of XMM-Newton. The X-ray flux is harder at orbital minimum, suggesting that the modulation is related to absorption, perhaps linked to the azimuthally asymmetric wind absorption seen previously in Hα.

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“…However, since there are no detailed calculation of ADAF-like flows for CVs in general the two-temperature flows can not be completely ruled out. Recently, Balman et al (2014) have shown that some Nova-like CVs have BLs that can be characterized with ADAFlike flows merged with optically thin BLs in high state CVs. These objects have accretion rates similar to or somewhat less than T Pyx.…”

Section: Central Source/binarymentioning

confidence: 99%

Pre-outburstChandraobservations of the recurrent nova T Pyxidis

Balman

2014

A&A

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Aims. I study the spectral, temporal, and spatial characteristics of the quiescent X-ray emission (not in outburst) of the recurrent nova T Pyx. Methods. I performed the spectral analysis of the X-ray data obtained using the Chandra Observatory, Advanced CCD Imaging Spectrometer (ACIS-S3) detector. I fit the spectra with several models that describe plasma emission characteristics. In addition, I calculated the light curve of the data and performed power spectral analysis using Fourier transform. Finally, I did high-resolution imaging analysis of the data at the subpixel level and produced radial surface brightness profiles.Results. I present a total of 98.8 ks (∼3 × 30 ks) observation of T Pyx obtained with the ACIS-S3 detector onboard the Chandra Observatory obtained during the quiescent phase, about 2−3 months before its outburst in April 2011. The total Chandra spectrum of the source T Pyx gives a maximum temperature kT max > 37.0 keV (2σ lower limit) with (0.9−1.5) × 10 −13 erg s −1 cm −2 and (1.3−2.2) × 10 32 erg s −1 (at 3.5 kpc) in the 0.1−50 keV range using a multitemperature plasma emission model with a power-law distribution of temperatures (i.e., CEVMKL in XSPEC). I find a ratio of (L x /L disk ) (2−7) × 10 −4 and the ratio is smaller if L disk is higher than 3 × 10 35 erg s −1 indicating considerable inefficiency of emission in the boundary layer. There is no soft X-ray blackbody emission from T Pyx with a 2σ upper limit on the blackbody temperature and the flux/luminosity as kT BB < 25 eV and L soft < 2.0 × 10 33 erg s −1 in the 0.1−10.0 keV band. All fits yield only interstellar N H during quiescence. I suggest that T Pyx has an optically thin boundary layer merged with an advection-dominated accretion flow and/or X-ray corona in the inner disk indicating ongoing quasi-spherical accretion at (very) high rates during quiescent phases. Such a boundary layer structure may be excessively heating the white dwarf, influencing the thermonuclear runaway leading to the recurrent nova events. The orbital period of the system is detected in the power spectrum of the Chandra light curves with no energy dependence over the orbit. The central source (i.e., the binary system) emission and its spectrum is deconvolved from any possible extended emission with a long and detailed procedure at the subpixel level revealing an extended emission with S /N ∼ 6−10. The derived shape looks like an elliptical nebula with a semi-major axis ∼1.0 arcsec and a semi-minor axis ∼0.5 arcsec, also indicating an elongation towards south. The calculated approximate count rate of the extended emission is 0.0013−0.0025 c s −1 . The luminosity (within errors) of the nebula is ∼(0.6−30.0) × 10 31 erg s −1 (at 3.5 kpc) mostly correct towards the lower end of the range. The nebulosity seems consistent with an interaction of the outflow/ejecta from the 1966 outburst.

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SWIFTX-RAY TELESCOPE OBSERVATIONS OF THE NOVA-LIKE CATACLYSMIC VARIABLES MV Lyr, BZ Cam, AND V592 Cas

Cited by 28 publications

References 100 publications

XMM–Newton observation of MV Lyr and the sandwiched model confirmation

XMM–Newton observation of MV Lyr and the sandwiched model confirmation

X-ray and UV observations of V751 Cygni in an optical high state

Pre-outburstChandraobservations of the recurrent nova T Pyxidis

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