After about 18 years of steadily spinning down , the accretion–powered pulsar 4U 1626-67 , experienced a new torque reversal at the beginning of 2008 .
For the present study we have used all available Fermi /GBM data since its launch in 2008 June 11 and over 5 yr of hard X-ray Swift /BAT observations ( starting from 2004 October up to the present time ) .
From 2004 up to the end of 2007 the spin–down rate averaged at a mean rate of \sim \dot { \nu } = -4.8 \times 10 ^ { -13 } Hz s ^ { -1 } until the torque reversal reported here .
This second detected torque reversal was centered near MJD 54500 ( 2008 Feb 4 ) and it lasted approximately 150 days .
During the reversal the source also underwent an increase in flux by a fraction of \sim 2.5 .
Since then it has been following a steady spin–up at a mean rate of \sim \dot { \nu } = 4 \times 10 ^ { -13 } Hz s ^ { -1 } .
We present a detailed long-term timing analysis of this source and a long term spectral hardness ratio study in order to see whether there are spectral changes around this new observed torque reversal .