<i>INTEGRAL</i>/IBIS and<i>Swift</i>/XRT observations of hard cataclysmic variables

Landi, R.; Bassani, L.; Dean, A. J.; Bird, A. J.; Fiocchi, M.; Bazzano, A.; Nousek, J. A.; Osborne, J. P.

doi:10.1111/j.1365-2966.2008.14086.x

Cited by 65 publications

(89 citation statements)

References 42 publications

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“…These authors attempted a combined XMM-INTEGRAL fit, and arrive at a temperature of 35 ± 10 keV, which they describe as "convincing agreement with the INTEGRAL data points". Though the Swift/BAT spectrum for MU Cam is the worst in terms of reduced χ 2 , we are (Barlow et al 2006) and (Landi et al 2009). 1: Masses, derived from the temperatures with the model of Aizu (1973 …”

Section: Discussion Of Individual Objectsmentioning

confidence: 92%

Intermediate polars in the Swift/BAT survey: spectra and white dwarf masses

Brunschweiger

Greiner

Ajello

et al. 2009

A&A

100

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Context. White dwarf masses in cataclysmic variables are difficult to determine accurately, but are fundamental for understanding binary system parameters, as well as binary evolution. Aims. We investigate the X-ray spectral properties of a sample of Intermediate Polars (IP) detected above 15 keV to derive the masses of their accreting white dwarfs. Methods. We use data from the Swift/BAT instrument which during the first 2.5 yrs of operation has detected 22 known intermediate polars. The X-ray spectra of these sources are used to estimate the mass of the white dwarfs. Results. We are able to produce a mass estimate for 22 out of 29 of the confirmed intermediate polars.Comparison with previous mass measurements shows good agreement. For GK Per, we were able to detect spectral changes due to the changes in the accretion rate. Conclusions. The Swift/BAT detector with its combination of sensitivity and all-sky coverage provides an ideal tool to determine accurate white dwarf masses in intermediate polars. This method should be applied to other magnetic white dwarf binaries.

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Section: Discussion Of Individual Objectsmentioning

confidence: 92%

Intermediate polars in the Swift/BAT survey: spectra and white dwarf masses

Brunschweiger

Greiner

Ajello

et al. 2009

A&A

100

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“…By doing this and letting the photon index of the blazar power law vary within the observed boundaries (1.44−1.88), it is possible to put more reasonable constraints on the CV bremsstrahlung temperature, which falls in the range 13−15 keV, i.e. closer to the values typically observed in this type of binary systems (Landi et al 2009). This information can in turn be used to describe the CV average spectrum seen by XRT.…”

Section: Spectral Analysismentioning

confidence: 93%

The counterpart/s of IGR J20159+3713/SWIFT J2015.9+3715: dissecting a complex region with emission from keV to TeV

Bassani¹,

Landi²,

Malizia³

et al. 2014

A&A

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We report on the identification of a new soft gamma-ray source, namely IGR J20159+3713/SWIFT J2015.9+3715, first detected by INTEGRAL/IBIS and then confirmed by Swift/BAT. The source, which has an observed 20-100 keV flux in the range (0.7−1.4)×10 −11 erg cm −2 s −1 , encloses a Fermi variable source (2FGL J2015.6+3709) and is spatially close to a TeV emitter (VER J2016+372). Thanks to X-ray follow-up observations performed with the X-ray telescope on board Swift, we have been able to identify the new IBIS/BAT detection with the combined emission of the blazar B2013+370 and the cataclysmic variable RX J2015.6+3711. Both objects show variability in X-rays, with the CV being the most variable of the two. At high energies (above 20 keV) the emission is likely dominated by B2013+370, but the contribution from RX J2015.6+3711 is not negligible. The blazar emits up to GeV frequencies where it is seen by Fermi, while the cataclysmic variable has a bremsstrahlung temperature which is too low to provide any contribution at these high energies. These findings also indicate that the INTEGRAL/Swift source is not associated with the TeV emission, which is most likely due to the supernova remnant (SNR)/pulsar wind nebula (PWN) CTB 87.

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“…GK Per is a bright hard X-ray source during the outbursts and it was observed by many X-ray observatories including EXOSAT (Watson et al 1985;Norton et al 1988), Ginga (Ishida et al 1992), ASCA (Ezuka & Ishida 1999), RXTE (Hellier et al 2004;Suleimanov et al 2005), XMM-Newton (Vrielmann et al 2005;Evans & Hellier 2007), Chandra (Mauche 2004), INTEGRAL (Barlow et al 2006;Landi et al 2009), and Swift/BAT (Brunschweiger et al 2009). Some of these observations were also used to estimate the WD mass.…”

Section: Gk Permentioning

confidence: 99%

GK Persei and EX Hydrae: Intermediate polars with small magnetospheres

Suleimanov

Doroshenko

Ducci

et al. 2016

A&A

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Observed hard X-ray spectra of intermediate polars are determined mainly by the accretion flow velocity at the white dwarf surface, which is normally close to the free-fall velocity. This allows us to estimate the white dwarf masses as the white dwarf mass-radius relation M − R and the expected free-fall velocities at the surface are well known. This method is widely used. However, derived white dwarf masses M can be systematically underestimated because the accretion flow is stopped at, and re-accelerates from, the magnetospheric boundary R m and, therefore, its velocity at the surface is lower than free fall. To avoid this problem, we computed a two-parameter set of model hard X-ray spectra, which allows us to constrain a degenerate M − R m dependence. Previous works showed that power spectra of accreting X-ray pulsars and intermediate polars exhibit breaks at frequencies corresponding to Keplerian frequencies at the magnetospheric boundary. Therefore, the break frequency ν b in an intermediate polar power spectrum gives another relation in the M − R m plane. The intersection of the two dependences allows us, therefore, to determine the white dwarf mass and magnetospheric radius simultaneously. To verify the method, we analysed the archival Suzaku observation of EX Hya, obtaining M/M = 0.73 ± 0.06 and R m /R = 2.6 ± 0.4, which is consistent with the values determined by other authors. Subsequently, we applied the same method to a recent NuSTAR observation of another intermediate polar GK Per performed during an outburst and found M/M = 0.86 ± 0.02 and R m /R = 2.8 ± 0.2. The long duration observations of GK Per in quiescence performed by Swift/BAT and INTEGRAL observatories indicate increase of magnetosphere radius R m at lower accretion rates.

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INTEGRAL/IBIS andSwift/XRT observations of hard cataclysmic variables

Cited by 65 publications

References 42 publications

Intermediate polars in the Swift/BAT survey: spectra and white dwarf masses

Intermediate polars in the Swift/BAT survey: spectra and white dwarf masses

The counterpart/s of IGR J20159+3713/SWIFT J2015.9+3715: dissecting a complex region with emission from keV to TeV

GK Persei and EX Hydrae: Intermediate polars with small magnetospheres

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