SGUERA, VITOVITOSGUERASIDOLI, LaraLaraSIDOLIPAIZIS, ADAMANTIAADAMANTIAPAIZISMASETTI, NICOLANICOLAMASETTIBird, A. J.A. J.BirdBAZZANO, ANGELAANGELABAZZANO2020-09-032020-09-0320170035-8711http://hdl.handle.net/20.500.12386/27072We present the results from INTEGRAL and Swift/XRT observations of the hitherto poorly studied unidentified X-ray transient AX J1949.8+2534, and on archival multiwavelength observations of field objects. Bright hard X-ray outbursts have been discovered above 20 keV for the first time, the measured duty cycle and dynamic range are of the order of ∼4 per cent and ≥ 630, respectively. The source was also detected during a low soft X-ray state (∼2 × 10<SUP>-12</SUP> erg cm<SUP>-2</SUP> s<SUP>-1</SUP>) thanks to a Swift/XRT followup, which allowed for the first time to perform a soft X-ray spectral analysis as well as significantly improve the source positional uncertainty from arcminute to arcsecond size. From archival near-infrared data, we pinpointed two bright objects as most likely counterparts whose photometric properties are compatible with an early-type spectral nature. This strongly supports a high-mass X-ray binary (HMXB) scenario for AX J1949.8+2534, specifically a Supergiant Fast X-ray Transient (more likely) or alternatively a Be HMXB.STAMPAenArticle10.1093/mnras/stx11112-s2.0-85051375938000406837900010https://academic.oup.com/mnras/article/469/4/3901/38134362017MNRAS.469.3901SFIS/05 - ASTRONOMIA E ASTROFISICA