A Second Glitch from the "Anomalous" X-Ray Pulsar 1RXS J170849.0-4000910

We report on 5.4 yr of phase-coherent timing, using the Rossi X-ray TimingExplorer, of the X-ray pulsar 1RXS 1708-4009, a member of the class known as``anomalous X-ray pulsars.'' This object exhibited a rotational glitch in 1999.Here we report a second much larger rotational glitch which occured ~1.5 yrafter the first. We show that the recoveries from the two glitches aredifferent, with the first showing only a possible slow, approximately linearrecovery, while the second showed a nearly complete recovery on a time scale of\~50 days. The approximately exponential recovery time scale of the secondglitch is similar to that seen recently in 1E 2259+586 at the time of a majoroutburst. This suggests 1RXS 1708-4009 undergoes similar bursting behavior,although with our sparse observations we have detected no other evidence forbursts from this source.Comment: 13 pages, 2 figures. Revised manuscript and Fig 1 following refereeing. Accepted for publication in ApJL Aug 1