2021MNRAS.506.2156B -
Mon. Not. R. Astron. Soc., 506, 2156-2169 (2021/September-2)
Pulsating iron spectral features in the emission of X-ray pulsar V 0332+53.
BYKOV S.D., FILIPPOVA E.V., GILFANOV M.R., TSYGANKOV S.S., LUTOVINOV A.A. and MOLKOV S.V.
Abstract (from CDS):
We present results of phase- and time-resolved study of iron spectral features in the emission of the Be/X-ray transient pulsar V 0332+53 during its type II outburst in 2004 using archival RXTE/PCA data. Coherent pulsations of both fluorescent iron line at ≃6.4 keV and neutral iron K-edge at ≃7.1 keV have been detected throughout the entire outburst. The pulsating iron K-edge is reported for the first time for this object. Near the peak of the outburst, the 3-12 keV pulse profile shows two deep, Fmax/Fmin ∼ 2, and narrow dips of nearly identical shape, separated by exactly Δph = 0.5 in phase. The dip spectra are nearly identical to each other and very similar in shape to the spectra outside the dips. The iron K-edge peaks at the phase intervals corresponding to the dips, although its optical depth τK ∼ 0.05 is by far insufficient to explain the dips. The iron line shows pulsations with a complex pulse profile without any obvious correlation with the total flux or optical depth of the K-edge. Accounting for the component associated with reprocessing of the pulsar emission by the surface of the donor star and circumstellar material, we find a very high pulsation amplitude of the iron line flux, Fmax/Fmin ∼ 10. We demonstrate that these properties of V 0332+53 cannot be explained by contemporary emission models for accreting X-ray pulsars and speculate about the origin of the observed iron spectral features.
Abstract Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
pulsars: individual: V 0332+53 - X-rays: binaries
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Simbad objects:
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