PONTI, GABRIELEGABRIELEPONTIJin, C.C.JinDe Marco, B.B.De MarcoRea, N.N.ReaRau, A.A.RauHaberl, F.F.HaberlCoti Zelati, F.F.Coti ZelatiBozzo, E.E.BozzoFerrigno, C.C.FerrignoBower, G. C.G. C.BowerDemorest, P.P.Demorest2020-07-172020-07-1720160035-8711http://hdl.handle.net/20.500.12386/26485We report on the identification of the new Galactic Centre (GC) transient Swift J174540.7-290015 as a likely low-mass X-ray binary located at only 16 arcsec from Sgr A<SUP>⋆</SUP>. This transient was detected on 2016 February 6, during the Swift GC monitoring, and it showed long-term spectral variations compatible with a hard- to soft-state transition. We observed the field with XMM-Newton on February 26 for 35 ks, detecting the source in the soft state, characterized by a low level of variability and a soft X-ray thermal spectrum with a high energy tail (detected by INTEGRAL up to ∼50 keV), typical of either accreting neutron stars or black holes. We observed: (I) a high column density of neutral absorbing material, suggesting that Swift J174540.7-290015 is located near or beyond the GC and; (II) a sub-Solar iron abundance, therefore we argue that iron is depleted into dust grains. The lack of detection of Fe K absorption lines, eclipses or dipping suggests that the accretion disc is observed at a low inclination angle. Radio (Very Large Array) observations did not detect any radio counterpart to Swift J174540.7-290015. No evidence for X-ray or radio periodicity is found. The location of the transient was observed also in the near-infrared (near-IR) with gamma-ray burst optical near-IR detector at MPG/European Southern Observatory La Silla 2.2 m telescope and VLT/NaCo pre- and post-outburst. Within the Chandra error region, we find multiple objects that display no significant variations.STAMPAenArticle10.1093/mnras/stw13822-s2.0-84983770627000383481100031https://academic.oup.com/mnras/article/461/3/2688/26084892016MNRAS.461.2688PFIS/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_6 Stars and stellar systems