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Optical identification of four hard X-ray sources from the Swift all-sky survey

2012; Pleiades Publishing; Volume: 38; Issue: 5 Linguagem: Inglês

10.1134/s1063773712050040

1562-6873

A. Lutovinov, R. Burenin, M. Revnivtsev, S. Sazonov, O. Sholukhova, A. F. Valeev,

Gamma-ray bursts and supernovae

We present the results of our optical identifications of four hard X-ray sources from the Swift all-sky survey. We obtained optical spectra for each of the program objects with the 6-m BTA telescope (Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz), which allowed their nature to be established. Two sources (SWIFT J2237.2+6324 and SWIFT J2341.0+7645) are shown to belong to the class of cataclysmic variables (suspected polars or intermediate polars). The measured emission line width turns out to be fairly large (FWHM ∼ 15–25 Å), suggesting the presence of extended, rapidly rotating (v ≃ 400–600 km s−1) accretion disks in the systems. Apart from line broadening, we have detected a change in the positions of the line centroids for SWIFT J2341.0+7645, which is most likely attributable to the orbital motion of the white dwarf in the binary system. The other two program objects (SWIFT J0003.3+2737 and SWIFT J0113.8+2515) are extragalactic in origin: the first is a Seyfert 2 galaxy and the second is a blazar at redshift z = 1.594. Apart from the optical spectra, we provide the X-ray spectra for all sources in the 0.6–10 keV energy band obtained from XRT/Swift data.