2020MNRAS.496.1768D -
Mon. Not. R. Astron. Soc., 496, 1768-1783 (2020/August-1)
Comprehensive analysis of the transient X-ray pulsar MAXI J1409-619.
DONMEZ C.K., SERIM M.M., INAM S.C., SAHINER S., SERIM D. and BAYKAL A.
Abstract (from CDS):
We probe the properties of the transient X-ray pulsar MAXI J1409-619 through RXTE and Swift follow-up observations of the outburst in 2010. We are able to phase-connect the pulse arrival times for the 25 d episode during the outburst. We suggest that either an orbital model (with Porb ≃ 14.7(4) d) or a noise process due to random torque fluctuations (with Sr ≃ 1.3 x 10–18 Hz2 s–2 Hz–1) is plausible to describe the residuals of the timing solution. The frequency derivatives indicate a positive torque-luminosity correlation, which implies temporary accretion disc formation during the outburst. We also discover several quasi-periodic oscillations in company with their harmonics whose centroid frequencies decrease as the source flux decays. The variation of the pulsed fraction and spectral power-law index of the source with X-ray flux is interpreted as the sign of transition from a critical to a sub-critical accretion regime at the critical luminosity within the range of 6 x 1037-1.2 x 1038 erg s–1. Using pulse-phase-resolved spectroscopy, we show that the phases with higher flux tend to have lower photon indices, indicating that the polar regions produce spectrally harder emission.
Abstract Copyright:
© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
stars: neutron - pulsars: individual: MAXI J1409-619 - accretion - accretion discs
Simbad objects:
13
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