Tandem Swift and INTEGRAL Data to Revisit the Orbital and Superorbital Periods of 1E 1740.7-2942

Abstract

The black hole candidate 1E 1740.7-2942 is one of the strongest hard X-ray sources in the Galactic Center region. No counterparts in longer wavelengths have been identified for this object yet. The presence of characteristic timing signatures in the flux history of X-ray sources has been shown to be an important diagnostic tool for the properties of these systems. Using simultaneous data from NASA's Swift and ESA's INTEGRAL missions, we have found two periodic signatures at 12.61 $\pm$ 0.06 days and 171.1 $\pm$ 3.0 days in long-term hard X-ray light curves of 1E 1740.7-2942. We interpret those as the orbital and superorbital periods of the object, respectively. The reported orbital period is in good agreement with previous studies of 1E 1740.7-2942 using NASA's RXTE data. We present here the first firm evidence of a superorbital period for 1E 1740.7-2942, which has important implications for the nature of the binary system.

4 pages, 7 figures

References in corpus (4)

• X-ray Properties of Black-Hole Binaries
• A Comparison of the Variability of the Symbiotic X-ray Binaries GX 1+4, 4U 1954+31, and 4U 1700+24 from Swift/BAT and RXTE/ASM Observations
• Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state
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Cited by in corpus (3)

• A catalogue of high-mass X-ray binaries in the Galaxy: from the INTEGRAL to the Gaia era
• Broadband X-ray analysis of 1E 1740.7-2942: constraints on spin, inclination and a tentative black hole mass
• On the behavior of the black hole candidate 1E 1740.7-2942's corona based on long-term INTEGRAL database