A decade of timing an accretion-powered millisecond pulsar: The continuing spin down and orbital evolution of SAX J1808.4-3658 Export

@article{citeulike:4043006, abstract = {The Rossi X-ray Timing Explorer has observed five outbursts from the transient 2.5 ms accretion-powered pulsar SAX J1808.4-3658 during 1998-2008. We present a pulse timing study of the most recent outburst and compare it with the previous timing solutions. The spin frequency of the source continues to decrease at a rate of (-5.5+/-1.2)x10^-18 Hz/s, which is consistent with the previously determined spin derivative. The spin-down occurs mostly during quiescence, and it is most likely due to the magnetic dipole torque from a B = 1.5x10^8 G dipolar field at the neutron star surface. We also find that the 2 hr binary orbital period is increasing at a rate of (3.80+/-0.06)x10^-12 s/s, also consistent with previous measurements. It remains uncertain whether this orbital change reflects secular evolution or short-term variability.}, archivePrefix = {arXiv}, author = {Hartman, J. M. and Patruno, A. and Chakrabarty, D. and Markwardt, C. B. and Morgan, E. H. and van der Klis, M. and Wijnands, R.}, citeulike-article-id = {4043006}, citeulike-linkout-0 = {http://arxiv.org/abs/0902.2112}, citeulike-linkout-1 = {http://arxiv.org/pdf/0902.2112}, day = {12}, eprint = {0902.2112}, keywords = {1808, timing}, month = {Feb}, posted-at = {2009-02-17 16:45:57}, priority = {2}, title = {A decade of timing an accretion-powered millisecond pulsar: The continuing spin down and orbital evolution of SAX J1808.4-3658}, url = {http://arxiv.org/abs/0902.2112}, year = {2009} }

TY - JOUR ID - citeulike:4043006 L3 - citeulike-article-id:4043006 N2 - The Rossi X-ray Timing Explorer has observed five outbursts from the transient 2.5 ms accretion-powered pulsar SAX J1808.4-3658 during 1998-2008. We present a pulse timing study of the most recent outburst and compare it with the previous timing solutions. The spin frequency of the source continues to decrease at a rate of (-5.5+/-1.2)x10^-18 Hz/s, which is consistent with the previously determined spin derivative. The spin-down occurs mostly during quiescence, and it is most likely due to the magnetic dipole torque from a B = 1.5x10^8 G dipolar field at the neutron star surface. We also find that the 2 hr binary orbital period is increasing at a rate of (3.80+/-0.06)x10^-12 s/s, also consistent with previous measurements. It remains uncertain whether this orbital change reflects secular evolution or short-term variability. TI - A decade of timing an accretion-powered millisecond pulsar: The continuing spin down and orbital evolution of SAX J1808.4-3658 KW - 1808 KW - timing AU - Hartman, JM AU - Patruno, A AU - Chakrabarty, D AU - Markwardt, CB AU - Morgan, EH AU - van der Klis, M AU - Wijnands, R PY - 2009/Feb/12/ UR - http://arxiv.org/abs/0902.2112 ER -