Speaker
Description
Ultraluminous X-ray sources (ULXs) are the brightest known non-nuclear X-ray binaries with luminosities exceeding the classical Eddington limit of a 10 $\rm M_\odot$ black hole. Recent discoveries of neutron star cores in ULXs confirm that the Eddington ratio can be a few hundred. Broadband spectral studies are pivotal to deciphering the emission mechanism in these mysterious sources. Here we discuss the accretion mechanism in a soft ultraluminous X-ray source NGC 6946 X-1. The broadband X-ray spectra of this source show quasi-steady nature in different epochs of observation. Two thermal emission components primarily govern the continuum. One originates from the inner accretion flow from a slim accretion disk, and the other is associated with an optically thick wind due to super-critical accretion. We also discuss some physical properties of the source based on the assumption of a realistic inclination angle of the accretion disk. The implication of a low massive black hole ($\rm \sim 6-10 ~M_\odot$) or a neutron star of weak magnetic field ($\rm B \leq 2 \times 10^{11}$ G) confirms the super-Eddington accreting nature of this source.
| Presentation Type | Oral |
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