X-ray luminosities of optically selected cataclysmic variables and application to the Galactic ridge X-ray emission

Reis, R. C.; Wheatley, P. J.; Gänsicke, B. T.; Osborne, J. P.

doi:10.1093/mnras/stt025

Cited by 49 publications

(53 citation statements)

References 94 publications

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“…For example, while the detailed propeller model of Matthews et al (2007) can still explain WZ Sge, it fails to explain GW Lib, whose outburst properties are similar to those of WZ Sge. On a possibly related note, the X-ray luminosity of WZ Sge is low compared to dwarf novae with frequent outbursts (U Gem and SU UMa types; Byckling et al 2010), while it is higher than that of GW Lib or the Sloanselected systems studied by Reis et al (2013). Given this, future studies should strive to understand why the quiescent accretion rate in WZ Sge is high compared to other WZ Sge systems and not why it is lower than in normal dwarf novae.…”

Section: On the Quiescent Rate Of Accretionmentioning

confidence: 97%

XMM-NewtonandSwiftobservations of WZ Sagittae: spectral and timing analysis

Nucita

Kuulkers

Paolis

et al. 2014

A&A

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Context. WZ Sagittae is the prototype object of a subclass of dwarf novae with rare and long (super)outbursts, in which a white dwarf primary accretes matter from a low mass companion. High-energy observations offer the possibility of a better understanding of the disk-accretion mechanism in WZ Sge-like binaries. Aims. We used archival XMM-Newton and Swift data to characterize the X-ray spectral and temporal properties of WZ Sge in quiescence. Methods. We performed a detailed timing analysis of the simultaneous X-ray and UV light curves obtained with the EPIC and OM instruments on board XMM-Newton in 2003. We employed several techniques in this study, including a correlation study between the two curves. We also performed an X-ray spectral analysis using the EPIC data and Swift/XRT data obtained in 2011.Results. We find that the X-ray intensity is clearly modulated at a period of 28.96 s, confirming previously published preliminary results. We find that the X-ray spectral shape of WZ Sge remains practically unchanged between the XMM-Newton and Swift observations. However, after correcting for interstellar absorption, the intrinsic luminosity is estimated to be L

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Section: On the Quiescent Rate Of Accretionmentioning

confidence: 97%

XMM-NewtonandSwiftobservations of WZ Sagittae: spectral and timing analysis

Nucita

Kuulkers

Paolis

et al. 2014

A&A

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“…The PL component describes the magnetospheric emission while BB or NSA refer to the thermal emission from the NS surface. We also tried the absorbed twotemperature optically thin thermal plasma (mekal) model (Mewe, Gronenschild & van den Oord 1985) which is usually used to describe spectra of cataclysmic variables (CVs) (see, e.g., Baskill et al 2005;Reis et al 2013). The cooler component describes the emission from the unshocked accretion flow and white dwarf photosphere while the hotter one describes the shocked flow emission.…”

Section: X-ray Spectramentioning

confidence: 99%

XMM–Newtonstudies of the supernova remnant G350.0−2.0

Карпова¹,

Shternin²,

Zyuzin³

et al. 2016

Mon. Not. R. Astron. Soc.

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We report the results of XMM-Newton observations of the Galactic mixed-morphology supernova remnant G350.0−2.0. Diffuse thermal X-ray emission fills the north-western part of the remnant surrounded by radio shell-like structures. We did not detect any X-ray counterpart of the latter structures, but found several bright blobs within the diffuse emission. The X-ray spectrum of the most part of the remnant can be described by a collisionally-ionized plasma model vapec with solar abundances and a temperature of ≈ 0.8 keV. The solar abundances of plasma indicate that the X-ray emission comes from the shocked interstellar material. The overabundance of Fe was found in some of the bright blobs. We also analysed the brightest point-like X-ray source 1RXS J172653.4−382157 projected on the extended emission. Its spectrum is well described by the two-temperature optically thin thermal plasma model mekal typical for cataclysmic variable stars. The cataclysmic variable source nature is supported by the presence of a faint (g ≈ 21) optical source with non-stellar spectral energy distribution at the X-ray position of 1RXS J172653.4−382157. It was detected with the XMM-Newton optical/UV monitor in the U filter and was also found in the archival Hα and optical/near-infrared broadband sky survey images. On the other hand, the X-ray spectrum is also described by the power law plus thermal component model typical for a rotation powered pulsar. Therefore, the pulsar interpretation of the source cannot be excluded. For this source, we derived the upper limit for the pulsed fraction of 27 per cent.

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“…There is also no sign of X-ray reflection, but again, this does not classify the source, since Fe reflection lines were seen in magnetic and non-magnetic CVs. Pretorius et al (2013), Reis et al (2013), Byckling et al (2010), andBaskill et al (2005). Luminosities given in certain spectral bands were corrected with bolometric correction factors using the spectral parameters given in the papers mentioned.…”

Section: Discussionmentioning

confidence: 99%

“…9 various CV subsamples are shown with well-determined distances, part of those were used to determine the space density and luminosity functions of CVs. Data were taken from Baskill et al (2005); Reis et al (2013); Pretorius & Knigge (2012); Pretorius et al (2013);Byckling et al (2010). Byckling et al (2010) were using a sample of non-magnetic CVs (dwarf novae, to be more precise) with parallax-based distance measurements to constrain the CV luminosity function.…”

Section: Discussionmentioning

confidence: 99%

“…Baskill et al (2005) presented the complete set of ASCA observations of non-magnetic CVs, only a subset has precise distances, hence luminosities. Reis et al (2013) studied a sample of optically selected (mostly SDSS) non-magnetic CVs which they followed with Swift to uncover the intrinsic differences in the X-ray properties of optically selected CVs and those that were discovered via other routes. Pretorius & Knigge (2012) and Pretorius et al (2013) were using X-ray selected CVs (mostly from the RBS) to derive space densities and uncover intrinsic differences between magnetic and nonmagnetic CVs.…”

Section: Discussionmentioning

confidence: 99%

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XMM-Newtonobservations of the low-luminosity cataclysmic variable V405 Pegasi

Schwope

Scipione

Traulsen

et al. 2014

A&A

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Context. V405 Peg is a low-luminosity cataclysmic variable (CV) that was identified as the optical counterpart of the bright, highlatitude ROSAT all-sky survey source RBS1955. The system was suspected to belong to a largely undiscovered population of hibernating CVs. Despite intensive optical follow-up its subclass however remained undetermined. Aims. We want to further classify V405 Peg and understand its role in the CV zoo via its long-term behaviour, spectral properties, energy distribution and accretion luminosity. Methods. We perform a spectral and timing analysis of XMM-Newton X-ray and ultra-violet data. Archival WISE, HST, and Swift observations are used to determine the spectral energy distribution and characterize the long-term variability.Results. The X-ray spectrum is characterized by emission from a multi-temperature plasma. No evidence for a luminous soft X-ray component was found. Orbital phase-dependent X-ray photometric variability by ∼50% occurred without significant spectral changes. No further periodicity was significant in our X-ray data. The average X-ray luminosity during the XMM-Newton observations was L X,bol 5 × 10 30 erg s −1 but, based on the Swift observations, the corresponding luminosity varied between 5 × 10 29 erg s −1 and 2 × 10 31 erg s −1 on timescales of years. Conclusions. The CV subclass of this object remains elusive. The spectral and timing properties show commonalities with both classes of magnetic and non-magnetic CVs. The accretion luminosity is far below than that expected for a standard accreting CV at the given orbital period. Objects like V405 Peg might represent the tip of an iceberg and thus may be important contributors to the Galactic Ridge X-ray Emission. If so they will be uncovered by future X-ray surveys, e.g. with eROSITA.

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X-ray luminosities of optically selected cataclysmic variables and application to the Galactic ridge X-ray emission

Cited by 49 publications

References 94 publications

XMM-NewtonandSwiftobservations of WZ Sagittae: spectral and timing analysis

XMM-NewtonandSwiftobservations of WZ Sagittae: spectral and timing analysis

XMM–Newtonstudies of the supernova remnant G350.0−2.0

XMM-Newtonobservations of the low-luminosity cataclysmic variable V405 Pegasi

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