2009/12/18 by A. Camero-Arranz, Camero-Arranz, A., Mark H. Finger +7 · 1 citation
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Mechanics and Biomechanics Studies #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.0912.3809
openalex publication_date 2009/12/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recent X-ray observations by Fermi/GBM discovered a new torque reversal of 4U 1626-67 after 18 years of steady spinning down. Using Swift/BAT observations we were able to center this new torque reversal on Feb 4 2008, lasting approximately 150 days. From 2004 up to the end of 2007, the spin-down rate averaged at a mean rate of ~dnu/dt=-4.8e-13 Hz s-1 until the torque reversal reported here. Since then it has been following a steady spin-up at a mean rate of ~dnu/dt= 4e-13 Hz s-1. The properties of this torque reversal, as well as the lack of correlation between the X-ray flux and the torque applied to the neutron star before this transition, challenges our understanding of the physical mechanisms operating in this system.