Aims: A growing number of previously hidden Galactic X-ray sources are now detected with recent surveys performed by the INTEGRAL and Swift satellites. Most of these new sources eluded past surveys due to their large local X-ray extinction and consequent low soft X-ray flux. The Swift-BAT performs daily monitoring of the sky in an energy band (15-150 keV) which is only marginally affected by X-ray extinction, thus allowing for the search of long periodicities in the light curve and identification of the nature of the X-ray sources. Methods: We performed a period search using the folding technique in the Swift-BAT light curves of three INTEGRAL sources: IGR J05007-7047, IGR J13186-6257 and IGR J17354-3255. Their periodograms show significant peaks at 30.77 ± 0.01 d, 19.99 ± 0.01 d and 8.448 ± 0.002 d, respectively. We estimate the significance of these features from the χ2 distribution of all the trials, finding a probability ≤ 1.5 × 10-4 that the detections occurred due to chance. We complement our analysis with the study of their broadband X-ray emission. Results: We identify the periodicities with the orbital periods of the sources. The periods are typical for the wind accretors X-ray binaries and we support this identification showing that also their energy spectra are compatible with an X-ray spectral emission characteristic of high-mass X-ray binaries. The spectrum of IGR J05007-704 that resides in the Large Magellanic Cloud, does not show any intrinsic local absorption, whereas the spectra of the Galactic sources IGR J17354-3255 and IGR J13186-6257 may be affected by a local absorber. The folded light curve for IGR J13186-6257 suggests a possible Be companion star.

D'Aì, A., La Parola, V., Cusumano, G., Segreto, A., Romano, P., Vercellone, S., et al. (2011). The Swift-BAT survey reveals the orbital period of three high-mass X-ray binaries. ASTRONOMY & ASTROPHYSICS, 529(A30) [10.1051/0004-6361/201016401].

The Swift-BAT survey reveals the orbital period of three high-mass X-ray binaries

D'AI', Antonino;ROBBA, Natale
2011-01-01

Abstract

Aims: A growing number of previously hidden Galactic X-ray sources are now detected with recent surveys performed by the INTEGRAL and Swift satellites. Most of these new sources eluded past surveys due to their large local X-ray extinction and consequent low soft X-ray flux. The Swift-BAT performs daily monitoring of the sky in an energy band (15-150 keV) which is only marginally affected by X-ray extinction, thus allowing for the search of long periodicities in the light curve and identification of the nature of the X-ray sources. Methods: We performed a period search using the folding technique in the Swift-BAT light curves of three INTEGRAL sources: IGR J05007-7047, IGR J13186-6257 and IGR J17354-3255. Their periodograms show significant peaks at 30.77 ± 0.01 d, 19.99 ± 0.01 d and 8.448 ± 0.002 d, respectively. We estimate the significance of these features from the χ2 distribution of all the trials, finding a probability ≤ 1.5 × 10-4 that the detections occurred due to chance. We complement our analysis with the study of their broadband X-ray emission. Results: We identify the periodicities with the orbital periods of the sources. The periods are typical for the wind accretors X-ray binaries and we support this identification showing that also their energy spectra are compatible with an X-ray spectral emission characteristic of high-mass X-ray binaries. The spectrum of IGR J05007-704 that resides in the Large Magellanic Cloud, does not show any intrinsic local absorption, whereas the spectra of the Galactic sources IGR J17354-3255 and IGR J13186-6257 may be affected by a local absorber. The folded light curve for IGR J13186-6257 suggests a possible Be companion star.
2011
D'Aì, A., La Parola, V., Cusumano, G., Segreto, A., Romano, P., Vercellone, S., et al. (2011). The Swift-BAT survey reveals the orbital period of three high-mass X-ray binaries. ASTRONOMY & ASTROPHYSICS, 529(A30) [10.1051/0004-6361/201016401].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/58402
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