The outburst of the X-ray nova GRS 1739-278 in September, 2016

Abstract

During the scanning observations of the Galactic Center region in August - September 2016 we detected the new outburst of the historical X-ray nova GRS 1739-278, the black hole candidate LMXB system. In this letter we present results of INTEGRAL and Swift-XRT observations taken during the outburst. In hard X-ray band (20-60 keV) the flux from the source raised from $\sim$11 to $\sim$30 mCrab between 3 and 14 of September. For nearly 8 days the source has been observed at this flux level and then faded to $\sim$15 mCrab. The broadband quasi-simultaneous spectrum obtained during the outburst is well described by the absorbed powerlaw with the photon index $\Gamma =1.86\pm 0.07$ in broad energy range 0.5-150 keV, with absorption corresponding to $N_H=2.3\times 10^{22}$ cm${}^{-2}$ assuming solar abundance. Based on this we can conclude that the source was in the low/hard state. From the lightcurve and spectra we propose that this outburst was `failed', i.e. amount of accreted matter was not sufficient to achieve the high/soft spectral state with dominant soft blackbody component as seen in normal outbursts of black hole candidates.

arXiv commentAccepted for publication in Astronomy Letters, 2017, 43, 3

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Cited by in corpus (5)

• The Swift Bulge Survey: Motivation, Strategy, and First X-ray Results
• State Transitions of GRS 1739$-$278 in the 2014 Outburst
• Studying temporal variability of GRS1739-278 during the 2014 outburst
• Investigation of the Outburst Activity of the Black Hole Candidate GRS 1739-278
• Morphology of the Light Curves for the X-ray Novae H1743-322 and GX339-4 during their Outbursts in 2005-2019