IGR J16328-4726: a new candidate Supergiant Fast X-ray Transient

Abstract

The unidentified source IGR J16328-4726 was covered with INTEGRAL observations for a long period (~9.8Ms) and was undetectable for most of the time while showing a very recurrent micro-activity with a duration from tens minutes to several hours. We report the discovery of two strong outbursts started at 53420.65 MJD and 54859.99 MJD respectively, the first with a duration of ~1 hour and the second with a lower limit on the duration of ~3.5 hours. Furthermore, the source have been detected in nine other short pointings with significance between 4 and 5 sigma as well as in a one of the revolution (during the exposure ~ 130 ks) at a significance level of ~7 sigma. The stronger outburst spectrum is well described by a power law model with a photon index of ~2.0 and a flux of ~3.3x10^{-10} erg cm^{-2} s^{-1} in the 20-50 keV energy band. The weaker outburst and revolution spectra show the same spectral shape and different fluxes. The combined timing and spectral properties observed during the outburst, the recurrent nature of this transient source, the Galactic Plane location, a dynamic range >170 in the 0.3-10 keV band and >165 in the 20-50 keV and the presence of a IR star in the error circle of an XRT/Swift pointing are suggesting this source as a member of the class of the Supergiant Fast X-ray Transients.

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• A description of sources detected by INTEGRAL during the first 4 years of observations
• Swift/XRT monitoring of the Supergiant Fast X-ray Transient IGR J18483-0311 for an entire orbital period
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Cited by in corpus (13)

• High-Mass X-ray Binaries in the Milky Way: A closer look with INTEGRAL
• Towards a unified view of inhomogeneous stellar winds in isolated supergiant stars and supergiant high mass X-ray binaries
• Advances in Understanding High-Mass X-ray Binaries with INTEGRAL and Future Directions
• Infrared identification of high-mass X-ray binaries discovered by INTEGRAL
• The 100-month Swift catalogue of supergiant fast X-ray transients I. BAT on-board and transient monitor flares
• XMM-Newton observations of four high mass X-ray binaries and IGR J17348-2045
• Soft X-ray characterisation of the long term properties of Supergiant Fast X-ray Transients
• The INTEGRAL source IGR J16328-4726: a High Mass X-ray Binary from the Beppo SAX era
• The Swift Supergiant Fast X-ray Transients Project: a review, new results, and future perspectives
• X-ray, optical and infrared investigation of the candidate Supergiant Fast X-ray Transient IGR J18462-0223
• The 100-month Swift catalogue of supergiant fast X-ray transients II. SFXT diagnostics from outburst properties
• The XMM Newton and INTEGRAL observations of the supergiant fast X-ray transient IGR J16328-4726
• Identification of 12 High Mass X-Ray Binaries detected by INTEGRAL through NIR photometry and spectroscopy