X-rays from cataclysmic variables

Kuulkers, E.; Norton, A. J.; Schwope, A. D.; Warner, Brian D.

doi:10.1017/cbo9780511536281.011

Cited by 69 publications

(71 citation statements)

References 210 publications

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“…At an assumed distance of 3 kpc, the absorption-corrected flux (0.3-79 keV) of the bremsstrahlung model translates to an X-ray luminosity of 5 × 10 33 erg s −1 . This is consistent with the persistent Xray luminosity expected from a CV (e.g., Muno et al 2004;Kuulkers et al 2006). …”

Section: Cxou J1633551−473804supporting

confidence: 85%

INITIAL RESULTS FROMNuSTAROBSERVATIONS OF THE NORMA ARM

Bodaghee

Tomsick

Krivonos

et al. 2014

ApJ

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Results are presented for an initial survey of the Norma Arm gathered with the focusing hard X-ray telescope NuSTAR. The survey covers 0.2 deg 2 of sky area in the 3-79 keV range with a minimum and maximum raw depth of 15 ks and 135 ks, respectively. Besides a bright black-hole X-ray binary in outburst (4U 1630−47) and a new X-ray transient (NuSTAR J163433−473841), NuSTAR locates three sources from the Chandra survey of this region whose spectra are extended above 10 keV for the first time: CXOU J163329.5−473332, CXOU J163350.9−474638, and CXOU J163355.1−473804. Imaging, timing, and spectral data from a broad X-ray range (0.3-79 keV) are analyzed and interpreted with the aim of classifying these objects. CXOU J163329.5−473332 is either a cataclysmic variable or a faint low-mass X-ray binary. CXOU J163350.9−474638 varies in intensity on year-long timescales, and with no multi-wavelength counterpart, it could be a distant X-ray binary or possibly a magnetar. CXOU J163355.1−473804 features a helium-like iron line at 6.7 keV and is classified as a nearby cataclysmic variable. Additional surveys are planned for the Norma Arm and Galactic Center, and those NuSTAR observations will benefit from the lessons learned during this pilot study.

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Section: Cxou J1633551−473804supporting

confidence: 85%

INITIAL RESULTS FROMNuSTAROBSERVATIONS OF THE NORMA ARM

Bodaghee

Tomsick

Krivonos

et al. 2014

ApJ

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“…Kuulkers et al 2006). The X-ray spectra of IPs can generally be represented by a hard bremsstrahlung continuum with a temperature of a few tens of keV with the addition of various emission lines (including the Fe Kα lines), sometimes with the inclusion of a soft thermal excess commonly represented by a BB component with kT < 0.5 keV (Kuulkers et al 2006).…”

Section: Discussionmentioning

confidence: 99%

A New 626 s periodic X-ray source in the direction of the Galactic center

Farrell

Gosling

Webb

et al. 2010

A&A

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Aims. Here we report the detection of a 626 s periodic modulation from the X-ray source 2XMM J174016.0−290337 located in the direction of the Galactic center. Methods. We present temporal and spectral analyses of archival XMM-Newton data and photometry of archived near-infrared data in order to investigate the nature of this source. Results. We find that the X-ray light curve shows a strong modulation at 626 ± 2 s with a confidence level >99.9% and a pulsed fraction of 54%. Spectral fitting demonstrates that the spectrum is consistent with an absorbed power law. No significant spectral variability was observed over the 626 s period. We have investigated the possibility that the 626 s period is orbital in nature (either that of an ultra-compact X-ray binary or an AM CVn) or related to the spin of a compact object (either an accretion powered pulsar or an intermediate polar). Conclusions. The X-ray properties of the source and the photometry of the candidate near-infrared counterparts are consistent with an accreting neutron star X-ray binary on the near-side of the Galactic bulge, where the 626 s period is most likely indicative of the pulsar spin period. However, we cannot rule out an ultra-compact X-ray binary or an intermediate polar with the data at hand. In the former case, if the 626 s modulation is the orbital period of an X-ray binary, it would be the shortest period system known. In the latter case, the modulation would be the spin period of a magnetic white dwarf. However, we find no evidence for absorption dips over the 626 s period, a low temperature black body spectral component, or Fe Kα emission lines. These features are commonly observed in intermediate polars, making 2XMM J174016.0−290337 a rather unusual member of this class if confirmed. Based on the slow period and the photometry of the near-infrared counterparts, we instead suggest that 2XMM J174016.0−290337 could be a new addition to the emerging class of symbiotic X-ray binaries.

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“…Depending on the intensity of the WD magnetic field, CVs are classified as: (i) non-magnetic systems, which have a very weak field (< ∼ 0.1 MG) in which an accretion disk forms around the compact object; (ii) intermediate polars (with magnetic field in the range 0.1-10 MG), where the accretion disk is disrupted in the vicinity of the WD; or (iii) polars (highly magnetized systems, > ∼ 10 MG), where the accretion occurs primarily by means of a mass stream. For a detailed description of the main properties of CVs, we refer to Kuulkers et al (2006).…”

Section: Introductionmentioning

confidence: 99%

The X-ray eclipse of the dwarf nova HT Cassiopeiae observed by theXMM-Newton satellite: spectral and timing analysis

Nucita¹,

Maiolo

Carpano

et al. 2009

A&A

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Context.A cataclysmic variable is a binary system consisting of a white dwarf that accretes material from a secondary object via the Roche-lobe mechanism. In the case of long enough observation, a detailed temporal analysis can be performed, allowing the physical properties of the binary system to be determined. Aims. We present an XMM-Newton observation of the dwarf nova HT Cas acquired to resolve the binary system eclipses and constrain the origin of the X-rays observed. We also compare our results with previous ROSAT and ASCA data. Methods. After the spectral analysis of the three EPIC camera signals, the observed X-ray light curve was studied with well known techniques and the eclipse contact points obtained. Results. The X-ray spectrum can be described by thermal bremsstrahlung of temperature kT 1 = 6.89 ± 0.23 keV plus a black-body component (upper limit) with temperature kT 2 = 30 +8 −6 eV. Neglecting the black-body, the bolometric absorption corrected flux is F Bol = (6.5 ± 0.1) × 10 −12 erg s −1 cm −2 , which, for a distance of HT Cas of 131 pc, corresponds to a bolometric luminosity of (1.33 ± 0.02) × 10 31 erg s −1 . In a standard accretion scenario where L BL 0.125L acc assuming Ω WD 0.5Ω K (R WD ), the amount of matter accreting onto the central white dwarf is found to be 1.7 × 10 −11 M yr −1 . The study of the eclipse in the EPIC light curve permits us to constrain the size and location of the X-ray emitting region, which turns out to be close to the white dwarf radius. We measure an X-ray eclipse somewhat smaller (but only at a level of 1.5σ) than the corresponding optical one. If this is the case, we have possibly identified the signature of either high latitude emission or a layer of X-ray emitting material partially obscured by an accretion disk.

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X-rays from cataclysmic variables

Cited by 69 publications

References 210 publications

INITIAL RESULTS FROMNuSTAROBSERVATIONS OF THE NORMA ARM

INITIAL RESULTS FROMNuSTAROBSERVATIONS OF THE NORMA ARM

A New 626 s periodic X-ray source in the direction of the Galactic center

The X-ray eclipse of the dwarf nova HT Cassiopeiae observed by theXMM-Newton satellite: spectral and timing analysis

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