Long Term Radiative Behavior of SGR 1900+14

Abstract

The prolific magnetar SGR 1900+14 showed two outbursts in the last decade and has been closely monitored in the X-rays to track the changes in its radiative properties. We use archival Chandra and XMM-Newton observations of SGR 1900+14 to construct a history of its spectrum and persistent X-ray flux spanning a period of about seven years. We show that the decline of its X-ray flux in these two outburst episodes follows the same trend. The flux begins to decline promptly and rapidly subsequent to the flares, then decreases gradually for about 600 days, at which point it resumes a more rapid decline. Utilizing the high quality spectral data in each epoch, we also study the spectral coevolution of the source with its flux. We find that neither the magnetic field strength nor the magnetospheric properties change over the period spanned by the observations, while the surface temperature as well as the inferred emitting area both decline with time following both outbursts. We also show that the source reached the same minimum flux level in its decline from these two subsequent outbursts, suggesting that this flux level may be its steady quiescent flux.

Accepted for publication in the ApJ

References in corpus (5)

• The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars
• Magnetars as persistent hard X-ray sources: INTEGRAL discovery of a hard tail in SGR 1900+14
• The first XMM-Newton observations of the Soft Gamma-ray Repeater SGR 1900+14
• The Magnetar Nature and the Outburst Mechanism of a Transient Anomalous X-ray Pulsar
• Five years of SGR 1900+14 observations with BeppoSAX

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