@article{2d413f9d28c44a74b84b9b8f11395e2e,
title = "IGR J17329-2731: The birth of a symbiotic X-ray binary",
abstract = "We report on the results of the multiwavelength campaign carried out after the discovery of the INTEGRAL transient IGR J17329-2731. The optical data collected with the SOAR telescope allowed us to identify the donor star in this system as a late M giant at a distance of 2.7-1.2+3.4 kpc. The data collected quasi-simultaneously with XMM-Newton and NuSTAR showed the presence of a modulation with a period of 6680 ± 3 s in the X-ray light curves of the source. This unveils that the compact object hosted in this system is a slowly rotating neutron star. The broadband X-ray spectrum showed the presence of a strong absorption ({\^a}1023 cm-2) and prominent emission lines at 6.4 keV, and 7.1 keV. These features are usually found in wind-fed systems, in which the emission lines result from the fluorescence of the X-rays from the accreting compact object on the surrounding stellar wind. The presence of a strong absorption line around ~21 keV in the spectrum suggests a cyclotron origin, thus allowing us to estimate the neutron star magnetic field as ~2.4 × 1012 G. All evidencethus suggests IGR J17329-2731 is a symbiotic X-ray binary. As no X-ray emission was ever observed from the location of IGR J17329-2731 by INTEGRAL (or other X-ray facilities) during the past 15 yr in orbit and considering that symbiotic X-ray binaries are known to be variable but persistent X-ray sources, we concluded that INTEGRAL caught the first detectable X-ray emission from IGR J17329-2731 when the source shined as a symbiotic X-ray binary. The Swift XRT monitoring performed up to ~3 months after the discovery of the source, showed that it maintained a relatively stable X-ray flux and spectral properties.",
keywords = "X-rays: binaries, X-rays: individuals: IGR J17329-2731",
author = "E. Bozzo and A. Bahramian and C. Ferrigno and A. Sanna and J. Strader and F. Lewis and Russell, {D. M.} and {Di Salvo}, T. and L. Burderi and A. Riggio and A. Papitto and P. Gandhi and P. Romano",
note = "Funding Information: Acknowledgements. The multiwavelength campaign promptly triggered after the discovery of IGR J17329-2731 was made possible thanks to the SMARTNet community (Middleton et al. 2017) and the available online tool (http://www.isdc.unige.ch/smartnet). We are grateful to the XMM–Newton, NuSTAR, and Swift teams for the effort in scheduling the ToO observations of IGR J17329-2731. This work made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). We also made use of observations obtained with XMM–Newton and INTEGRAL, which are two ESA science missions with instruments and contributions directly funded by ESA Member States and NASA. The paper is also based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Minist{\'e}rio da Ci{\^e}ncia, Tecnologia, Inova{\c c}{\~a}os e Comunica{\c c}{\~a}oes (MCTIC) do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). The Faulkes Telescope Project is an education partner of LCO. The Faulkes Telescopes are maintained and operated by LCO. EB and PR acknowledge financial contribution from the agreement ASI-INAF I/037/12/0. We acknowledge financial contribution from the agreement ASI-INAF I/037/12/0. AB thanks T.J.Maccarone and R. Wijnands for helpful discussions. AP acknowledges funding from the EUs Horizon 2020 Framework Programme for Research and Innovation under the Marie Sk{\l}odowska-Curie Individual Fellowship grant agreement 660657-TMSP-H2020-MSCA-IF-2014. JS acknowledges support from the Packard Foundation. We thank the anonymous referee for detailed comments that helped us improve the paper. Publisher Copyright: {\textcopyright} ESO 2018.",
year = "2018",
month = may,
day = "1",
doi = "10.1051/0004-6361/201832588",
language = "English (US)",
volume = "613",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
}