Recent Torque Reversal of 4U 1907+09

Abstract

We present timing and spectral analysis of RXTE-PCA observations of the accretion powered pulsar 4U 1907+09 between June 2007 and August 2008. 4U 1907+09 had been in a spin-down episode with a spin-down rate of $-3.54\times 10^{-14}$ Hz s${}^{-1}$ before 1999. From RXTE observations after March 2001, the source showed a $\sim 60$% decrease in spin-down magnitude and INTEGRAL observations after March 2003 showed that source started to spin-up. We found that the source recently entered a new spin-down episode with a spin-down rate of $-3.59\times 10^{-14}$ Hz s${}^{-1}$. This spin-down rate is pretty close to the previous long term spin-down rate of the source measured before 1999. From the spectral analysis, we showed that Hydrogen column density varies with the orbital phase.

Published in MNRAS

References in corpus (13)

• Magnetic Fields of Accreting X-Ray Pulsars with the Rossi X-Ray Timing Explorer
• RXTE Measurement of the Diffuse X-ray Emission From the Galactic Ridge: Implications for the Energetics of the Interstellar Medium
• On the Dramatic Spin-up/Spin-down Torque Reversals in Accreting Pulsars
• The X-ray emission of the supernova remnant W49B observed with XMM-Newton
• Recent X-ray measurements of the accretion-powered pulsar 4U 1907+09
• On the spin-up/spin-down transitions in accreting X-ray binaries
• Warped Disks as a Possible Origin of Torque Reversals in Accretion-Powered Pulsars
• Disk Accretion onto Magnetized Neutron Stars: The Inner Disk Radius and Fastness Parameter
• Torque Reversal in Accretion-Powered X-ray Pulsars
• A torque reversal of 4U 1907+09
• The Steady Spin Down Rate of 4U 1907+09
• Accretion disk reversal and the spin-up/spin-down of accreting pulsars
• Evidence of a Change in the Long Term Spin-down Rate of the X-ray Pulsar 4U 1907+09

Cited by in corpus (16)

• New Torque Reversal and Spin-Up of 4u 1626- 67 Observed by Fermi/GBM and Swift/BAT
• Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with INTEGRAL
• A Comprehensive Spectral Analysis of the X-Ray Pulsar 4U 1907+09 from Two Observations with the Suzaku X-Ray Observatory
• Pulse phase dependent variations of the cyclotron absorption features of the accreting pulsars A 0535+26, XTE J1946+274 and 4U 1907+09 with Suzaku
• A Comprehensive Study on RXTE & INTEGRAL Observations of the X-ray Pulsar 4U 1907+09
• Pulse Phase Variation of Cyclotron Line in HMXB 4U 1907+09 with ASTROSAT LAXPC
• On the Torque Reversals of Accreting Neutron Stars
• XMM-Newton and Swift observations of supergiant high mass X-ray binaries
• On the torque reversals of 4U 1626--67
• Detection of nearly periodic spin period reversals in Vela X-1 on long time-scales: inkling of solar-like cycle in the donor star?
• Properties and observability of glitches and anti-glitches in accreting pulsars
• GRMHD simulations of accreting neutron stars I: nonrotating dipoles
• A high-mass X-ray binary pulsar 4U 1907+09 with multiple absorption-line features in the spectrum
• Long-term evolution of Cyclotron Line energy in an eclipsing pulsar 4U 1538-522
• Long-term spin-down and low luminosity regime in the Be/X-ray binary pulsar GX 304-1
• Variability study of classical supergiant X-ray binary 4U 1907+09 using NuSTAR