arXiv:0707.3037 [astro-ph]AbstractReferencesReviewsResources Classifications Subjects Themes Keywords optical counterpart, quiescence, accretion-powered millisecond x-ray pulsar igr, sixth accretion-powered millisecond x-ray pulsar, hr orbital period Tags journal article Journal Information Publisher Journal Year Month Volume Number Pages DOI URL Miscellaneous Typesetting Pages Language License Submit Reset