Aims. We present the first X-ray observations with the XMM-Newton and INTEGRAL satellites of the recently discovered cataclysmic variable 1RXS J173021.5-055933, together with simultaneous UV and coordinated optical photometry aiming at characterising its broad-band temporal and spectral properties and classifying this system as a magnetic one. Methods. We performed a timing analysis of the X-ray, UV, and optical light curves to identify and to study the energy dependence of the fast 128 s pulsation over a wide energy range. X-ray spectral analysis in the broad 0.2-100 keV X-ray range was performed to characterise the peculiar emission properties of this source. Results. We find that the X-ray light curve is dominated by the spin period of the accreting white dwarf in contrast to the far-UV range, which turns out to be unmodulated at a 3 sigma level. Near-UV and optical pulses are instead detected at twice the spin frequency. We identify the contributions from two accreting poles that imply a moderately inclined dipole field allowing, one pole to dominate at energies at least up to 10 keV, and a secondary that instead is negligible above 5 keV. X-ray spectral analysis reveals the presence of multiple emission components consisting of optically thin plasma with temperatures ranging from 0.17 keV to 60 keV and a hot blackbody at similar to 90 eV. The spectrum is also strongly affected by peculiar absorption components consisting of two high-density (similar to 3 x 10(21) cm(-2) and 2 x 10(23) cm(-2)) intervening columns, plus a warm absorber. The last is detected from an OVII absorption edge at 0.74 keV, which suggests that photoionization of pre-shock material is also occurring in this system. Conclusions. The observed properties indicate that the accretor in 1RXS J173021.5-055933 is a white dwarf with a likely weak magnetic field, thus confirming this cataclysmic variable as an intermediate polar (IP) with one of the most extreme spin-to-orbit period ratios. This system also joins the small group of IPs showing a soft X-ray reprocessed component, suggesting that this characteristics is not uncommon in these systems.

de Martino, D., Matt, G., Mukai, K., Bonnet Bidaud, J.m., Falanga, M., Gansicke, B.t., et al. (2008). 1RXS J173021.5-055933: a cataclysmic variable with a fast-spinning magnetic white dwarf. ASTRONOMY & ASTROPHYSICS, 481(1), 149-159 [10.1051/0004-6361:20078368].

1RXS J173021.5-055933: a cataclysmic variable with a fast-spinning magnetic white dwarf

MATT, Giorgio;
2008-01-01

Abstract

Aims. We present the first X-ray observations with the XMM-Newton and INTEGRAL satellites of the recently discovered cataclysmic variable 1RXS J173021.5-055933, together with simultaneous UV and coordinated optical photometry aiming at characterising its broad-band temporal and spectral properties and classifying this system as a magnetic one. Methods. We performed a timing analysis of the X-ray, UV, and optical light curves to identify and to study the energy dependence of the fast 128 s pulsation over a wide energy range. X-ray spectral analysis in the broad 0.2-100 keV X-ray range was performed to characterise the peculiar emission properties of this source. Results. We find that the X-ray light curve is dominated by the spin period of the accreting white dwarf in contrast to the far-UV range, which turns out to be unmodulated at a 3 sigma level. Near-UV and optical pulses are instead detected at twice the spin frequency. We identify the contributions from two accreting poles that imply a moderately inclined dipole field allowing, one pole to dominate at energies at least up to 10 keV, and a secondary that instead is negligible above 5 keV. X-ray spectral analysis reveals the presence of multiple emission components consisting of optically thin plasma with temperatures ranging from 0.17 keV to 60 keV and a hot blackbody at similar to 90 eV. The spectrum is also strongly affected by peculiar absorption components consisting of two high-density (similar to 3 x 10(21) cm(-2) and 2 x 10(23) cm(-2)) intervening columns, plus a warm absorber. The last is detected from an OVII absorption edge at 0.74 keV, which suggests that photoionization of pre-shock material is also occurring in this system. Conclusions. The observed properties indicate that the accretor in 1RXS J173021.5-055933 is a white dwarf with a likely weak magnetic field, thus confirming this cataclysmic variable as an intermediate polar (IP) with one of the most extreme spin-to-orbit period ratios. This system also joins the small group of IPs showing a soft X-ray reprocessed component, suggesting that this characteristics is not uncommon in these systems.
2008
de Martino, D., Matt, G., Mukai, K., Bonnet Bidaud, J.m., Falanga, M., Gansicke, B.t., et al. (2008). 1RXS J173021.5-055933: a cataclysmic variable with a fast-spinning magnetic white dwarf. ASTRONOMY & ASTROPHYSICS, 481(1), 149-159 [10.1051/0004-6361:20078368].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/125028
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