2008/11/06 by J. A. Zurita Heras, R. Walter
Physics and Astronomy · #Accretion (finance) #Astrophysical Phenomena and Observations #Binary number #Binary star #Flare #Flare star #Luminosity #Pulsar #Pulsars and Gravitational Waves Research #Spectral line #Stellar, planetary, and galactic studies #Supergiant #astro-ph
paper · pdf · doi:10.1051/0004-6361:200810219
7 pages, 5 figures, accepted for publication in Astronomy and Astrophysics
arxiv created 2008/11/06 · openalex publication_date 2008/12/11 · arxiv updated 2009/12/01 · openalex created_date 2017/10/20 · openalex updated_date 2026/08/05
<i>Aims. <i/>AX J1845.0-0433 is a transient high-mass X-ray binary discovered by <i>ASCA<i/>. The source displays bright and short flares observed by <i>INTEGRAL<i/>. The transient behaviour and bright and short flares are studied to understand both the accretion mechanisms and nature of the source.<i>Methods. <i/>Public <i>INTEGRAL<i/> data and a pointed <i>XMM-Newton<i/> observation are used to study in detail the flaring and quiescent phases.<i>Results. <i/>AX J1845.0-0433 is a persistent X-ray binary with a O9.5I supergiant companion, emitting at a low 0.2-100 keV luminosity of ~ with seldom flares and reaching luminosities of . The most accurately measured X-ray position is RA (2000)=18<sup>h<sup/>45<sup>m<sup/>01.4<sup>s<sup/> and Dec =-04 (2″). Variability factors of 50 are observed on timescales as short as hundreds of seconds. The broad-band spectrum is typical of wind-fed accreting pulsars with an intrinsic absorption of , a hard continuum of , and a high-energy cutoff at keV. An excess at low energies is also observed fitted with a black body with a temperature of keV. Optically-thin and highly-ionised iron (Fe XVIII-XIX) located close to the supergiant star is detected during the quiescence phase. The spectral shape of the X-ray continuum remains unchanged. In contrast to the persistent quiescent emission, the flare characteristics suggest that clumps of mass g are formed within the stellar wind of the supergiant companion.