SIMBAD references

2013MNRAS.433..528D - Mon. Not. R. Astron. Soc., 433, 528-542 (2013/July-3)

INTEGRAL and XMM-Newton observations of IGR J16418-4532: evidence of accretion regime transitions in a supergiant fast X-ray transient.


Abstract (from CDS):

We report on combined INTEGRAL and XMM-Newton observations of the supergiant fast X-ray transient (SFXT) IGR J16418-4532. The observations targeted the X-ray eclipse region of IGR J16418-4532's orbit with continuous INTEGRAL observations across ∼ 25 per cent of orbital phase and two quasi-simultaneous XMM-Newton observations of length 20 and 14ks, occurring during and just after the eclipse, respectively. An enhanced INTEGRAL emission history is provided with 19 previously unreported outbursts identified in the archival 18-60keV data set. The XMM-Newton eclipse observation showed prominent Fe emission and a flux of 2.8x10-13 ergcm-2s-1 (0.5-10keV). Through the comparison of the detected eclipse and post-eclipse flux, the supergiant mass-loss rate through the stellar wind was determined as {dot}Mw = 2.3-3.8x10-7 M☉yr-1. The post-eclipse XMM-Newton observation showed a dynamic flux evolution with signatures of the X-ray pulsation, a period of flaring activity, structured nH variations and the first ever detection of an X-ray intensity dip, or `off-state', in a pulsating SFXT. Consideration is given to the origin of the X-ray dip, and we conclude that the most applicable of the current theories of X-ray dip generation is that of a transition between Compton-cooling-dominated and radiative-cooling-dominated subsonic accretion regimes within the `quasi-spherical' model of wind accretion. Under this interpretation, which requires additional confirmation, the neutron star in IGR J16418-4532 possesses a magnetic field of ∼ 1014 G, providing tentative observational evidence of a highly magnetized neutron star in a SFXT for the first time. The implications of these results on the nature of IGR J16418-4532 itself and the wider SFXT class are discussed.

Abstract Copyright: © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2013)

Journal keyword(s): accretion, accretion discs - stars: winds, outflows - X-rays: binaries - X-rays: individual: IGR J16418-4532

CDS comments: Misprints: in introduction IGR J16465-4514 is IGR J16465-4507, p.541 IGR J18418-0311 is IGR J18483-0311, and IGR J16418-4514 is probably IGR J16418-4532.

Simbad objects: 15

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