Timing Noise in SGR 1806-20

Details Timing Noise in SGR 1806-20 Timing Noise in SGR 1806-20

2000-03-20

arxiv.org/abs/astro-ph/0003292v2

Astronomy and Astrophysics

Astrophysics

11 pages, accepted for publication in ApJ Letters

Scientific paper

10.1086/312698

We have phase connected a sequence of RXTE PCA observations of SGR 1806-20 covering 178 days. We find a simple secular spin-down model does not adequately fit the data. The period derivative varies gradually during the observations between 8.1 and 11.7 * 10^-11 s/s (at its highest, ~40% larger than the long term trend), while the average burst rate as seen with BATSE drops throughout the time interval. The phase residuals give no compelling evidence for periodicity, but more closely resemble timing noise as seen in radio pulsars. The magnitude of the timing noise, however, is large relative to the noise level typically found in radio pulsars. Combining these results with the noise levels measured for some AXPs, we find all magnetar candidates have \Delta_8 values larger than those expected from a simple extrapolation of the correlation found in radio pulsars. We find that the timing noise in SGR 1806-20 is greater than or equal to the levels found in some accreting systems (e.g., Vela X-1, 4U 1538-52 and 4U 1626-67), but the spin-down of SGR 1806-20 has thus far maintained coherence over 6 years. Alternatively, an orbital model with a period P_orb = 733 days provides a statistically acceptable fit to the data. If the phase residuals are created by Doppler shifts from a gravitationally bound companion, then the allowed parameter space for the mass function (small) and orbital separation (large) rule out the possibility of accretion from the companion sufficient to power the persistent emission from the SGR.

Affiliated with

Also associated with

No associations

Rating

Timing Noise in SGR 1806-20 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Timing Noise in SGR 1806-20, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Timing Noise in SGR 1806-20 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-392313