A Comprehensive Study on RXTE & INTEGRAL Observations of the X-ray Pulsar 4U 1907+09

Abstract

We analyse \emph{INTEGRAL} (between 2005 October and 2007 November) and \emph{RXTE} (between 2007 June and 2011 March) observations of the accretion powered pulsar 4U 1907+09. From \emph{INTEGRAL} IBIS-ISGRI and \emph{RXTE}-PCA observations, we update pulse period history of the source. We construct power spectrum density of pulse frequencies and find that fluctuations in the pulse frequency derivatives are consistent with the random walk model with a noise strength of $1.27\times 10^{-21}$ Hz s${}^{-2}$. From the X-ray spectral analysis of \emph{RXTE}-PCA observations, we find that Hydrogen column density is variable over the binary orbit, tending to increase just after the periastron passage. We also show that the X-ray spectrum gets hardened with decreasing X-ray flux. We discuss pulse-to-pulse variability of the source near dipping ingress and egress. We find that the source more likely undergoes in dipping states after apastron until periastron when the accretion from clumpy wind might dominate so that occasional transitions to temporary propeller state might occur.

19 pages, 8 figures, accepted for publication in MNRAS

References in corpus (8)

• High variability in Vela X-1: giant flares and off states
• Unveiling the nature of six HMXBs through IR spectroscopy
• Study of the many fluorescent lines and the absorption variability in GX 301-2 with XMM-Newton
• A torque reversal of 4U 1907+09
• Discovery of a Peculiar Dip from GX 301-2
• Recent Torque Reversal of 4U 1907+09
• Timing and X-ray Spectral Features of Swift J1626.6-5156
• RXTE-PCA Observations of XMMU J054134.7-682550

Cited by in corpus (20)

• High-Mass X-ray Binaries in the Milky Way: A closer look with INTEGRAL
• Advances in Understanding High-Mass X-ray Binaries with INTEGRAL and Future Directions
• Observatory science with eXTP
• On the nature of `off' states in slowly rotating low-luminosity X-ray pulsars
• Supergiant, fast, but not so transient 4U 1907+09
• Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with INTEGRAL
• Wind accretion: Theory and Observations
• Pulse Phase Variation of Cyclotron Line in HMXB 4U 1907+09 with ASTROSAT LAXPC
• XMM-Newton spectroscopy of the accreting magnetar candidate 4U0114+65
• Astrophysical parameters and orbital solution of the peculiar X-ray transient IGR J00370+6122
• XMM-Newton and Swift observations of supergiant high mass X-ray binaries
• Spin evolution of long-period X-ray pulsars
• A semi-analytical treatment to wind accretion in neutron star supergiant high mass X-ray binaries: I. eccentric orbits
• Catalog of the Galactic population of X-ray pulsars in High-mass X-ray binary systems
• A high-mass X-ray binary pulsar 4U 1907+09 with multiple absorption-line features in the spectrum
• Comprehensive Timing and X-ray Spectral Analysis of GX 1+4
• Evidence for Magneto-Levitation Accretion in Long-Period X-ray Pulsars
• Variability study of classical supergiant X-ray binary 4U 1907+09 using NuSTAR
• Probing the polarized emission from the accretion-powered pulsar 4U 1907+09 with IXPE
• The Timing Noise of Magnetars