AAS 195th Meeting, January 2000
Session 126. Drizzling Down the Potential Well: Accreting Compact Objects II
Oral, Saturday, January 15, 2000, 2:00-3:30pm, Regency VII

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[126.08] Phase Connection of Burst Pulsations in KS 1731-260 and Aquila X-1

D. W. Fox, M. P. Muno, E. H. Morgan (MIT)

We have performed in-burst phase connection of the burst pulsations detected in type I X-ray bursts from the low-mass X-ray binaries KS~1731-260 and Aql~X-1. The train of pulsations in each of the bursts examined (two from KS~1731-260 and one from Aql~X-1) is greater than nine seconds in length and -- accounting for the systematic drift in frequency observed in all cases -- completely coherent for \gtrsim5000 cycles. Phase-connecting the pulsations allows us to characterize the frequency drift in a model-independent fashion: we find that the frequency evolution, in each case, is consistent with a \tau ~3s exponential relaxation to an asymptotic frequency. Exponential fits to the frequency evolution during the two bursts from KS~1731-260, although different in specific details, are remarkably similar; in particular, the stability of the asymptotic pulse frequency over the 2.6 year interval between the bursts sets a 2\sigma upper limit of |\dot{P}| < 3e-14 on the time-average period derivative for these oscillations. We suggest that our results further support the interpretation of the burst pulsations as reflecting the neutron star spin period in these systems.

If you would like more information about this abstract, please follow the link to http://space.mit.edu/~derekfox/. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser. [Previous] | [Session 126] | [Next]