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Astronomy and Astrophysics 481 (2008) 149-159
1RXSJ173021.5-055933: a cataclysmic variable with a fast-spinning magnetic white dwarf
D. de Martino, G. Matt1, K. Mukai, J.-M. Bonnet-Bidaud2, M. Falanga2, B. T. Gaensicke, F. Haberl, T. R. Marsh, M. Mouchet3, 4, S. P. Littlefair, V. Dhillon

We present the first X-ray observations with the XMM-Newton and INTEGRAL satellites of the recently discovered cataclysmic variable 1RXSJ173021.5-055933, 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. We find that the X-ray light curve is dominated by the 128s spin period of the accreting white dwarf in contrast to the far-UV range, which turns out to be unmodulated at a 3sigma 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 10keV, and a secondary that instead is negligible above 5keV. X-ray spectral analysis reveals the presence of multiple emission components consisting of optically thin plasma with temperatures ranging from 0.17keV to 60keV and a hot blackbody at ~90eV. The spectrum is also strongly affected by peculiar absorption components consisting of two high-density (~3x10^(21)cm^(-2) and ~2x10^(23)cm^(-2)) intervening columns, plus a warm absorber. The last is detected from an OVII absorption edge at 0.74keV, which suggests that photoionization of pre-shock material is also occurring in this system. The observed properties indicate that the accretor in 1RXSJ173021.5-055933 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.
1 :  Dipartimento di Fisica
2 :  DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
3 :  LUTH - Laboratoire Univers et Théories
4 :  APC - UMR 7164 - AstroParticule et Cosmologie
APC - Cosmologie et gravitation
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique

Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique

Planète et Univers/Astrophysique
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