SGR 1822-1606 (Swift 1822.3-1606): Spin-down rate and inferred dipole field strength
ATel #3503; Ersin Gogus (Sabanci Univ. Istanbul), Tod Strohmayer (NASA/GSFC), Chryssa Kouveliotou (NASA/MSFC), report on behalf of a larger tea
on 21 Jul 2011; 13:03 UT
Credential Certification: Ersin Gogus (ersing@sabanciuniv.edu)
Subjects: X-ray, Neutron Star, Soft Gamma-ray Repeater
We have been monitoring the new source Swift 1822.3-1606 (Cummings et al. GCN 12159) with RXTE. We acquired a total exposure of 20.6 ks in 5 pointings, spanning a time baseline of 5 days. We clearly detect the 8.44 s pulsations reported earlier (Pagani et al. ATel #3489, Gogus et al ATel #3491, Rea et al Atel #3501). We employed an epoch folding technique to determine the spin ephemeris. Our preliminary analysis reveal the spin period, P = 8.4377158(9) s and the spin-down rate, Pdot = 2.2(5) x 10^-11 s/s (Epoch: 55758.5 MJD). Assuming that the neutron star slows down via magnetic dipole radiation, we find an inferred dipole magnetic field strength of B = 4.3 x 10^14 G. These results. therefore, lend support to the magnetar nature of Swift 1822.3-1606 (SGR 1822-1606) and confirm the source as a Soft Gamma Repeater as originally classified by Cummings et al. (GCN 12159).
