Swift/BAT and RXTE Observations of the Peculiar X-ray Binary 4U 2206+54 - Disappearance of the 9.6 Day Modulation

Abstract

Observations of the high-mass X-ray binary 4U 2206+54 with the Swift Burst Alert Telescope (BAT) do not show modulation at the previously reported period of 9.6 days found from observations made with the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM). Instead, the strongest peak in the power spectrum of the BAT light curve occurs at a period of 19.25 +/- 0.08 days, twice the period found with the RXTE ASM. The maximum of the folded BAT light curve is also delayed compared to the maximum of the folded ASM light curve. The most recent ASM data folded on twice the 9.6 day period show similar morphology to the folded BAT light curve. This suggests that the apparent period doubling is a recent secular change rather than an energy-dependent effect. The 9.6 day period is thus not a permanent strong feature of the light curve. We suggest that the orbital period of 4U 2206+54 may be twice the previously proposed value.

arXiv commentAccepted for publication in The Astrophysical Journal

References in corpus (22)

• Observations of Accreting Pulsars
• First Results from the All-Sky Monitor on the Rossi X-ray Timing Explorer
• In-flight Performance of the High Energy X-ray Timing Experiment on the Rossi X-ray Timing Explorer
• The Swift/BAT High Latitude Survey: First Results
• A Systematic Search for Periodicities in RXTE/ASM Data
• Be/X-ray binaries and candidates: catalogue
• A Decade in the Life of EXO 2030+375: A Multi-wavelength Study of an Accreting X-ray Pulsar
• The transient X-ray pulsar 4U 0115+63 from quiescence to outburst through the centrifugal transition
• Recent X-ray measurements of the accretion-powered pulsar 4U 1907+09
• Wind accretion in the massive X-ray binary 4U 2206+54: abnormally slow wind and a moderately eccentric orbit
• Evidence for a Neutron Star in the non-pulsating massive X-ray binary 4U2206+54
• Multiwavelength monitoring of BD+53 2790, the optical counterpart to 4U~2206+54
• Discovery of the Orbit of the Transient X ray Pulsar SAX J2103.5+4545
• On the nature of the hard X-ray source 4U2206+54
• Discovery of pulsations in the X-ray transient 4U 1901+03
• Superorbital Period in the High Mass X-ray Binary 2S 0114+650
• A look with BeppoSAX at the low-luminosity Galactic X-ray source 4U 2206+54
• Further evidence for the presence of a neutron star in 4U 2206+54. INTEGRAL and VLA observations
• Discovery of the 198 s X-ray Pulsar GRO J2058+42
• 4U2206+54 - an Unusual High Mass X-ray Binary with a 9.6 Day Orbital Period but No Strong Pulsations
• Long Term X-ray Variability in GX13+1: Energy Dependent Periodic Modulation
• Discovery of a Be/X-ray Binary Consistent with the Position of GRO J2058+42

Cited by in corpus (39)

• Multiwavelength Evidence for Quasi-periodic Modulation in the Gamma-ray Blazar PG 1553+113
• Cyclotron lines in highly magnetized neutron stars
• Revisiting Quasi-Periodic modulation in $\gamma$-ray Blazar PKS 2155-304 with Fermi Pass 8 data
• Superorbital Periodic Modulation in Wind-Accretion High-Mass X-ray Binaries from Swift BAT Observations
• A Comparison of the Variability of the Symbiotic X-ray Binaries GX 1+4, 4U 1954+31, and 4U 1700+24 from Swift/BAT and RXTE/ASM Observations
• A $\gamma$-ray Quasi-Periodic modulation in the Blazar PKS 0301$-$243?
• Accreting magnetars: a new type of high-mass X-ray binaries?
• An Extended and More Sensitive Search for Periodicities in RXTE/ASM X-ray Light Curves
• Associating long-term gamma-ray variability with the superorbital period of LS I 61 303
• Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54
• Possible Quasi-Periodic modulation in the z = 1.1 $\gamma$-ray blazar PKS 0426-380
• Spin-Down of the Long-Period Accreting Pulsar 4U 2206+54
• Evidence for a magnetic neutron star in high mass X-ray binary 4U 2206+54 with INTEGRAL/IBIS observations
• Super-Orbital Variability in Hard X-rays
• Wind inhibition by X-ray irradiation in HMXBs: the influence of clumping and the final X-ray luminosity
• Properties of the 24 Day Modulation in GX 13+1 from Near-Infrared and X-ray Observations
• An XMM-Newton Spectral and Timing Study of IGR J16207-5129: An Obscured and Non-Pulsating HMXB
• Multi-scale time- and frequency-domain likelihood analysis with photon weights
• Periodic Gamma-ray Modulation of the blazar PG 1553+113 Confirmed by Fermi-LAT and Multi-wavelength Observations
• Long-term Hard X-ray Monitoring of 2S 0114+65 with INTEGRAL/IBIS
• Orbital parameters of the high-mass X-ray binary 4U 2206+54
• Diverse Long-Term Variability of Five Candidate High-Mass X-ray Binaries from Swift Burst Alert Telescope Observations
• NuSTAR rules out a cyclotron line in the accreting magnetar candidate 4U2206+54
• Spin and Spectral Variations of Peculiar High-Mass X-ray Binary 4U 2206+54
• XMM-Newton and Swift observations of supergiant high mass X-ray binaries
• On the spin-down mechanism of the X-ray pulsar 4U 2206+54
• Catalog of the Galactic population of X-ray pulsars in High-mass X-ray binary systems
• INTEGRAL/IBIS observations of a hard X-ray outburst in high mass X-ray binary 4U 2206+54
• INTEGRAL and Swift observations of IGRJ19294+1816 in outburst
• Discovery of a magnetic neutron star in X-ray transient IGR J01583+6713
• The Orbital Parameters of the Eclipsing High-Mass X-ray Binary Pulsar IGR J16493-4348 from Pulsar Timing
• Fast time optical variability in Be/X-ray binaries. Pulsation and rotation
• RXTE and BeppoSAX Observations of the Transient X-ray Pulsar XTE J1859+083
• Multi-wavelength observations of the Be/X-ray binary IGR J01217-7257 (=SXP 2.16) during outburst
• A gamma-ray periodic modulation in Globular Cluster 47 Tucanae
• Change in spin-down rate and detection of emission line in HMXB 4U 2206+54 with AstroSat observation
• Further evidence for natal kick segregation by spectral type in high-mass X-ray binaries
• Astrophysical parameters of LS 437 and the nature of X0726-260
• Long-term optical variability of high-mass X-ray binaries. III. Polarimetry