Discovery of X-ray pulsations in the Be/X-ray binary IGR J06074+2205

Abstract

IGR J06074+2205 is a poorly studied X-ray source with a Be star companion. It has been proposed to belong to the group of Be/X-ray binaries. In Be/X-ray binaries, accretion onto the neutron star occurs via the transfer of material from the Be star's circumstellar disk. Thus, in the absence of the disk, no X-ray should be detected. The main goal of this work is to study the quiescent X-ray emission of IGR J06074+2205 during a disk-loss episode. We show that at the time of the XMM-Newton observation the decretion disk around the Be star had vanished. Still, accretion appears as the source of energy that powers the high-energy radiation in IGR J06074+2205. We report the discovery of X-ray pulsations with a pulse period of 373.2 s and a pulse fraction of ~50%. The $0.4-12$ keV spectrum is well described by an absorbed power law and blackbody components with the best fitting parameters: $N_{\mathrm{H}}=(6.2\pm 0.5)\times 10^{21}$ cm${}^{-2}$, $k{T}_{\mathrm{bb}}=1.16\pm 0.03$ keV, and $\Gamma =1.5\pm 0.1$ The absorbed X-ray luminosity is $L_{\mathrm{X}}=1.4\times 10^{34}$ erg s${}^{-1}$ assuming a distance of 4.5 kpc. The detection of X-ray pulsations confirms the nature of IGR J06074+2205 as a Be/X-ray binary. We discuss various scenarios to explain the quiescent X-ray emission of this pulsar. We rule out cooling of the neutron star surface and magnetospheric emission and conclude that accretion is the most likely scenario. The origin of the accreted material remains an open question.

accepted for publication in A&A

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Cited by in corpus (10)

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• Advances in Understanding High-Mass X-ray Binaries with INTEGRAL and Future Directions
• Discovery of accretion-driven pulsations in the prolonged low X-ray luminosity state of the Be/X-ray transient GX 304-1
• Catalog of the Galactic population of X-ray pulsars in High-mass X-ray binary systems
• Fast time optical variability in Be/X-ray binaries. Pulsation and rotation
• First characterization of a new High Mass X-ray Binary in LMC eRASSU J050810.4$-$660653 with SRG/ART-XC, NuSTAR and Swift
• Further evidence for natal kick segregation by spectral type in high-mass X-ray binaries
• Detection of a cyclotron line in the Be X-ray pulsar IGR J06074$+$2205
• Long-term spin-down and low luminosity regime in the Be/X-ray binary pulsar GX 304-1
• Spectral and Timing properties of the recently discovered Be/X-ray pulsar eRASSUJ 052914.9-662446