Outburst of LS V+44 17 observed by MAXI and RXTE discovery of dip structure in pulse profile

Abstract

We report the discovery of a dip structure in the pulse profile of Be/X-ray binary LS V +44 17 observed by RXTE during an outburst detected by MAXI. The outburst was first transient activity of LS V +44 17 since 1997 when the source was identified as a Be/X-ray binary. After the discovery with MAXI, the RXTE observations provided a pulse profile with a narrow dip structure in the soft X-ray band (3–10 keV). Our pulse-phase-resolved spectroscopy showed that the absorption column density at the dip phase is much higher than those at the other intervals. Thus we can conclude that the partial eclipse of the emission region by the accretion column of the neutron star causes the dip structure in the pulse profile of LS V +44 17 during the first outburst.