X-ray measurement of a high-mass white dwarf and its spin for the intermediate polar IGR J18434-0508 - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2024

X-ray measurement of a high-mass white dwarf and its spin for the intermediate polar IGR J18434-0508

Julian Gerber
  • Fonction : Auteur
Jeremy Hare
  • Fonction : Auteur
John A Tomsick
  • Fonction : Auteur
Benjamin M Coughenour
  • Fonction : Auteur
Aarran W Shaw
  • Fonction : Auteur
Francesca Fornasini
  • Fonction : Auteur
Jules Halpern
  • Fonction : Auteur
Alyson Joens
  • Fonction : Auteur
Roman Krivonos
  • Fonction : Auteur
Koji Mukai
  • Fonction : Auteur

Résumé

IGR J18434-0508 is a Galactic Intermediate Polar (IP) type Cataclysmic Variable (CV) previously classified through optical spectroscopy. The source is already known to have a hard Chandra spectrum. In this paper, we have used follow-up XMM-Newton and NuSTAR observations to measure the white dwarf (WD) mass and spin period. We measure a spin period of P = 304.4 +/- 0.3 s based on the combined MOS1, MOS2, and pn light curve. Although this is twice the optical period found previously, we interpret this value to be the true spin period of the WD. The source has an 8 +/- 2% pulsed fraction in the 0.5-10 keV XMM-Newton data and shows strong dips in the soft energy band (0.5-2 keV). The XMM-Newton and NuSTAR joint spectrum is consistent with a thermal bremsstrahlung continuum model with an additional partial covering factor, reflection, and Fe line Gaussian components. Furthermore, we fit the joint spectrum with the post-shock region "ipolar" model which indicates a high WD mass $>$ $\sim$ 1.36 Msun, approaching the Chandrasekhar limit.

Dates et versions

hal-04541233 , version 1 (10-04-2024)

Identifiants

Citer

Julian Gerber, Jeremy Hare, John A Tomsick, Benjamin M Coughenour, Aarran W Shaw, et al.. X-ray measurement of a high-mass white dwarf and its spin for the intermediate polar IGR J18434-0508. Monthly Notices of the Royal Astronomical Society, 2024, 530 (1), pp.861-869. ⟨10.1093/mnras/stae896⟩. ⟨hal-04541233⟩
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