Details

Autor(en) / Beteiligte

• Rea, N.
• Zelati, F. Coti
• Esposito, P.
• D'Avanzo, P.
• de Martino, D.
• Israel, G. L.
• Torres, D. F.
• Campana, S.
• Belloni, T. M.
• Papitto, A.
• Masetti, N.
• Carrasco, L.
• Possenti, A.
• Wieringa, M.
• Wilhelmi, E. De Oña
• Li, J.
• Bozzo, E.
• Ferrigno, C.
• Linares, M.
• Tauris, T. M.
• Hernanz, M.
• Ribas, I.
• Monelli, M.
• Borghese, A.
• Baglio, M. C.
• Casares, J.

Titel

Multiband study of RX J0838−2827 and XMM J083850.4−282759: a new asynchronous magnetic cataclysmic variable and a candidate transitional millisecond pulsar

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2017-11, Vol.471 (3), p.2902-2916

Ort / Verlag

Oxford University Press

Erscheinungsjahr

2017

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Abstract In a search for the counterpart to the Fermi-LAT source 3FGL J0838.8−2829, we performed a multiwavelength campaign: in the X-ray band with Swift and XMM–Newton; in the infrared and optical with OAGH, ESO-NTT and IAC80; and in the radio with ATCA observations. We also used archival hard X-ray data obtained by INTEGRAL. We report on three X-ray sources consistent with the position of the Fermi-LAT source. We confirm the identification of the brightest object, RX J0838−2827, as a magnetic cataclysmic variable that we recognize as an asynchronous system (not associated with the Fermi-LAT source). RX J0838−2827 is extremely variable in the X-ray and optical bands, and timing analysis reveals the presence of several periodicities modulating its X-ray and optical emission. The most evident modulations are interpreted as being caused by the binary system orbital period of ∼1.64 h and the white dwarf spin period of ∼1.47 h. A strong flux modulation at ∼15 h is observed at all energy bands, consistent with the beat frequency between spin and orbital periods. Optical spectra show prominent Hβ, He i and He ii emission lines that are Doppler-modulated at the orbital period and at the beat period. Therefore, RX J0838−2827 accretes through a disc-less configuration and could be either a strongly asynchronous polar or a rare example of a pre-polar system on its way to reaching synchronism. Regarding the other two X-ray sources, XMM J083850.4−282759 showed a variable X-ray emission, with a powerful flare lasting for ∼600 s, similar to what is observed in transitional millisecond pulsars during the subluminous disc state: this observation possibly means that this source can be associated with the Fermi-LAT source.