Superorbital Modulation in the High-Mass X-ray Binary 4U 1538-52, and Possible Modulation in IGR J16393-4643

Abstract

Hard X-ray observations with the Neil Gehrels Swift Observatory Burst Alert Telescope (BAT) reveal superorbital modulation in the wind-accreting supergiant high-mass X-ray binary (HMXB) 4U 1538-52 at a period of 14.9130 +/- 0.0026 days that is consistent with four times the 3.73 day orbital period. These periods agree with a previously suggested correlation between superorbital and orbital periods in similar HMXBs. During the ~14 years of observations the superorbital modulation changes amplitude, and since ~MJD 57,650 it was no longer detected in the power spectrum, although a peak near the second harmonic of this was present for some time. Measurements of the spin period of the neutron star in the system with the Fermi Gamma-ray Burst Monitor show a long-term spin-down trend which halted towards the end of the light curve, suggesting a connection between dP(spin)/dt and superorbital modulation, as proposed for 2S 0114+650. However, an earlier torque reversal from INTEGRAL observations was not associated with superorbital modulation changes. B and V band photometry from the Las Cumbres Observatory reveals orbital ellipsoidal photometric variability, but no superorbital optical modulation. However the photometry was obtained when the 14.9130 day period was no longer detected in the BAT power spectrum. We revisit possible superorbital modulation in BAT observations of IGR J16393-4643 but cannot conclusively determine whether this is present, although is not persistent. We consider superorbital modulation mechanisms, and suggest that the Corotating Interaction Region model, with small deviations from orbital synchronization, appears promising.

arXiv commentAccepted for publication in the Astrophysical Journal. 15 pages, 16 figures

References in corpus (36)

• The Fermi Gamma-Ray Burst Monitor
• The Burst Alert Telescope (BAT) on the Swift MIDEX Mission
• Las Cumbres Observatory Global Telescope Network
• Observations of Accreting Pulsars
• The Swift/BAT Hard X-ray Transient Monitor
• Refined Neutron-Star Mass Determinations for Six Eclipsing X-Ray Pulsar Binaries
• Tidal Synchronization and Differential Rotation of Kepler Eclipsing Binaries
• The Ups & Downs of Accreting X-Ray Pulsars: Decade-long observations with the Fermi Gamma-Ray Burst Monitor
• Characterizing X-ray binary long-term variability
• Modeling Ultraviolet Wind Line Variability in Massive Hot Stars
• BRITE-Constellation high-precision time-dependent photometry of the early-O-type supergiant $\zeta$ Puppis unveils the photospheric drivers of its small- and large-scale wind structures
• Superorbital Periodic Modulation in Wind-Accretion High-Mass X-ray Binaries from Swift BAT Observations
• Orbital Decay and Evidence of Disk Formation in the X-ray Binary Pulsar OAO 1657-415
• Giant outburst from the supergiant fast X-ray transient IGR J17544-2619: accretion from a transient disc?
• Optical precursors to X-ray binary outbursts
• A Detailed Study of 2S 0114+650 with the RXTE
• Bondi-Hoyle-Lyttleton accretion in Supergiant X-ray binaries: stability and disk formation
• Eccentric binaries: Tidal flows and periastron events
• The X-ray binary 2S0114+650=LSI+65 010:A slow pulsar or tidally-induced pulsations?
• Superorbital Period in the High Mass X-ray Binary 2S 0114+650
• Seven Years with the Swift Supergiant Fast X-ray Transients Project
• Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with INTEGRAL
• Orbital and super-orbital periods in ULX pulsars, disc-fed HMXBs, Be/X-ray binaries and double-periodic variables
• Evolution of Spin, Orbital, and Superorbital Modulations of 4U 0114+650
• Chandra observations of five INTEGRAL sources: new X-ray positions for IGR J16393-4643 and IGR J17091-3624
• NuSTAR discovery of a cyclotron line in the accreting X-ray pulsar IGR J16393-4643
• The First NuSTAR Observation of 4U 1538-522: Updated Orbital Ephemeris and A Strengthened Case for an Evolving Cyclotron Line Energy
• Probing the Masses and Radii of Donor Stars in Eclipsing X-ray Binaries with the Swift Burst Alert Telescope
• Recent Timing Studies on RXTE Observations of 4U 1538-52
• The donor star of the X-ray pulsar X1908+075
• Diverse Long-Term Variability of Five Candidate High-Mass X-ray Binaries from Swift Burst Alert Telescope Observations
• On the super-orbital modulation of supergiant high mass X-ray binaries
• Understanding the coexistence of spin-up and spin-down behaviors in long period X-ray pulsars
• A Study of the 20 Day Superorbital Modulation in the High-Mass X-ray Binary IGR J16493-4348
• The Orbital Parameters of the Eclipsing High-Mass X-ray Binary Pulsar IGR J16493-4348 from Pulsar Timing
• Investigating a unique partial eclipse in the High Mass X-ray Binary IGR J16393-4643 with Swift-XRT

Cited by in corpus (5)

• A catalogue of high-mass X-ray binaries in the Galaxy: from the INTEGRAL to the Gaia era
• XMM-Newton and Swift observations of supergiant high mass X-ray binaries
• Investigating the superorbital modulations in 4U 1909+07, IGR J16418-4532 and IGR J16479-4514 with Swift XRT, BAT and NuSTAR observations
• Pulse Frequency Fluctuations of Persistent Accretion Powered Pulsars
• Swift/XRT monitoring of the orbital and superorbital modulations in 4U 1909+07