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

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

Monthly Notices of the Royal Astronomical Society, Volume 471, Issue 3, p.2902-2916

Advertised on:
11
2017
Number of authors
26
IAC number of authors
3
Citations
27
Refereed citations
25
Description
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.
Related projects
A view of our Milky Way galaxy with its close neighbors the Magellanic Clouds
Galaxy Evolution in the Local Group
Galaxy formation and evolution is a fundamental Astrophysical problem. Its study requires “travelling back in time”, for which there are two complementary approaches. One is to analyse galaxy properties as a function of red-shift. Our team focuses on the other approach, called “Galactic Archaeology”. It is based on the determination of galaxy
Matteo
Monelli
Black hole in outburst
Black holes, neutron stars, white dwarfs and their local environment
Accreting black-holes and neutron stars in X-ray binaries provide an ideal laboratory for exploring the physics of compact objects, yielding not only confirmation of the existence of stellar mass black holes via dynamical mass measurements, but also the best opportunity for probing high-gravity environments and the physics of accretion; the most
Montserrat
Armas Padilla