Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 9502

RXTE Discovery of Pulsations from SGR 0418+5729
2009-06-10T15:43:29Z (15 years ago)
Ersin Gogus at Sabanci U/Turkey <>
Ersin Gogus (Sabanci Univ.), Chryssa Kouveliotou (NASA/NSSTC), Peter M. 
Woods (Dynetics)
report on behalf of a larger collaboration:

Following the Fermi GBM/Konus/Swift detection of bursts from the new 
Soft Gamma
Repeater SGR 0418+5729 (van der Horst et al. 2009, GCN #9499) we 
triggered our
SGR ToO Program with RXTE. A 6.8 ks RXTE observation started on 2009 
June 10,
03:42:56 UT. We detect a strong, coherent pulsations from the new SGR 
(2-10 keV)
in the PCA GoodXenon mode data at 0.110152(2) Hz, corresponding to a 
spin period
of 9.0783(1) sec. The pulse morphology is complex showing two asymmetric 
per cycle.  We note that there is no previously known X-ray source in 
the RXTE field
of view with such periodicity. The detected coherent pulsations likely 
indicate the spin
period of the newly discovered, burst-active SGR. 
We thank the project scientist Jean Swank, and the RXTE planner, Divya 
Pereira for
the prompt scheduling of the RXTE observations.
Looking for U.S. government information and services? Visit