IGR J17329-2731: The birth of a symbiotic X-ray binary

Bozzo, E.E.BozzoBahramian, A.A.BahramianFerrigno, C.C.FerrignoSANNA, ALBERTOALBERTOSANNAStrader, J.J.StraderLewis, F.F.LewisRussell, D. M.D. M.Russelldi Salvo, T.T.di SalvoBurderi, L.L.BurderiRiggio, A.A.RiggioPAPITTO, ALESSANDROALESSANDROPAPITTOGandhi, P.P.GandhiROMANO, PatriziaPatriziaROMANO2021-02-022021-02-0220180004-6361http://hdl.handle.net/20.500.12386/30150We 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 (≫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.STAMPAenIGR J17329-2731: The birth of a symbiotic X-ray binaryArticle10.1051/0004-6361/2018325882-s2.0-85048059790000432981200007https://www.aanda.org/articles/aa/abs/2018/05/aa32588-18/aa32588-18.html2018A&A...613A..22BFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_10 High energy and particle astronomy – X-rays, cosmic rays, gamma rays, neutrinos