SGR 1822-1606: Constant Spin Period
ATel #3543; M. Serim (METU/Ankara), A. Baykal (METU/Ankara), S. C. Inam (Baskent Univ./Ankara)
on 10 Aug 2011; 11:58 UT
Credential Certification: Sitki Cagdas Inam (inam@baskent.edu.tr)
Subjects: X-ray, Neutron Star, Soft Gamma-ray Repeater, Pulsar
Referred to by ATel #: 3553
We have analyzed light curve of the new source SGR 1822-1606 (Cummings et al.
GCN 12159) using the real time data of RXTE observations.
We have extracted light curve for 11 pointings with a time span of about
20 days and employed pulse timing analysis
using the harmonic representation of pulses. Using the cross correlation
of harmonic representation of pulses, we have obtained pulse arrival times.
We have found that pulse period is stable at 8.4377202(4)s. Our results indicate that
spin period rate is constant with a value of Pdot 1.2 \pm 1.8 * 10^{-12} s/s which is consistent with zero. The upper
limit of spin down rate is about 37 times weaker than the rate reported earlier
(Gogus et al. #Atel 3503) for a time span of 5 days observations. The source might be a magnetar
with a magnetic field of less than about 7.2 * 10^{13} G if a constant spin down is resolved or it might be an
X-ray binary type source if the pulse arrival times show Doppler shifts. Future monitoring
of the source is valuable in order to understand nature of the source.
Figure: Pulse arrival times fitted to the quadratic corresponding to the current spin rate value: http://www.baskent.edu.tr/~inam/1822/1822_current.ps
