Chandra and rxte observations of 1E 1547.0-5408: Comparing the 2008 and 2009 outbursts

C. Y. Ng, V. M. Kaspi, R. Dib, S. A. Olausen, P. Scholz, T. Güver, Feryal Ozel, F. P. Gavriil, P. M. Woods

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Abstract

We present results from Chandra X-ray Observatory and Rossi X-ray Timing Explorer (RXTE) observations of the magnetar 1E 1547.0-5408 (SGR J1550-5418) following the source's outbursts in 2008 October and 2009 January. During the time span of the Chandra observations, which covers days 4 through 23 and days 2 through 16 after the 2008 and 2009 events, respectively, the source spectral shape remained stable in the Chandra band, while the pulsar's spin-down rate in the same span in 2008 increased by a factor of 2.2 as measured by RXTE. This suggests decoupling between the source's spin-down and radiative changes, hence between the spin-down-inferred magnetic field strength and that inferred spectrally. The lack of spectral variation during flux decay is surprising for models of magnetar outbursts. We also found a strong anti-correlation between the phase-averaged flux and the pulsed fraction in the 2008 and 2009 Chandra data, but not in the pre-2008 measurements. We discuss these results in the context of the magnetar model.

Original languageEnglish (US)
Article number131
JournalAstrophysical Journal
Volume729
Issue number2
DOIs
Publication statusPublished - Mar 10 2011

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Keywords

  • pulsars: individual (1E 1547.0?5408, PSR J1550?5418, SGR J1550?5418)
  • stars: neutron
  • X-rays: bursts

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Ng, C. Y., Kaspi, V. M., Dib, R., Olausen, S. A., Scholz, P., Güver, T., ... Woods, P. M. (2011). Chandra and rxte observations of 1E 1547.0-5408: Comparing the 2008 and 2009 outbursts. Astrophysical Journal, 729(2), [131]. https://doi.org/10.1088/0004-637X/729/2/131