The spin-down of Swift J1834.9-0846: confirmation as magnetar
ATel #3577; L. Kuiper (SRON) and W. Hermsen (SRON, UvA)
on 23 Aug 2011; 12:24 UT
Credential Certification: Lucien Kuiper (L.M.Kuiper@sron.nl)
Subjects: X-ray, Gamma Ray, Neutron Star, Soft Gamma-ray Repeater, Transient, Pulsar
Referred to by ATel #: 3600
Data from monitoring observations with RXTE PCA and Swift XRT of
Swift J1834.9-0846 (GRB110807A) covering a time span of about 2 weeks (MJD 55782-55795)
since its discovery on August 7, 2011 (GCN #12253; GCN #12255) have been
used to construct an accurate phase-coherent timing solution using barycentered
(see GCN #12253 for the source position) pulse arrival times (ToA's) obtained
by cross-correlation with a pulse-profile template.
Fitting two frequency parameters to the TOA set (5 XRT/3 PCA observations)
we obtained, Nu = 0.40285190(8) Hz, consistent with the value derived by Gogus
(ATEL #3542), and dNu/dt = -1.3(2)E-12 Hz/s for Epoch 55783.0 MJD (TDB timescale).
Adopting the canonical magnetic-dipole braking model the estimated surface polar
magnetic field is 1.4E14 Gauss, well above the quantum critical value of 4.413E13
Gauss, and thus confirming the magnetar nature of Swift J1834.9-0846.
The characteristic time scale (age) is 4960 year.
