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Extended tails from SGR 1806-20 bursts

Göğüş, Ersin and Woods, Peter M. and Kouveliotou, Chryssa and Finger, Mark H. and Pal'shin, Valentin and Kaneko, Yuki and Golenetskii, Sergey and Frederiks, Dmitry and Airhart, Carol (2011) Extended tails from SGR 1806-20 bursts. Astrophysical Journal, 740 (2). ISSN 0004-637X

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Official URL: http://dx.doi.org/10.1088/0004-637X/740/2/55

Abstract

In 2004, SGR 1806-20 underwent a period of intense and long-lasting burst activity that included the giant flare of 2004 December 27—the most intense extra-solar transient event ever detected at Earth. During this active episode, we routinely monitored the source with Rossi X-ray Timing Explorer and occasionally with Chandra. During the course of these observations, we identified two relatively bright bursts observed with Konus-Wind in hard X-rays that were followed by extended X-ray tails or afterglows lasting hundreds to thousands of seconds. Here, we present detailed spectral and temporal analysis of these events observed about 6 and 1.5 months prior to the 2004 December 27 giant flare. We find that both X-ray tails are consistent with a cooling blackbody of constant radius. These spectral results are qualitatively similar to those of the burst afterglows recorded from SGR 1900+14 and recently from SGR 1550–5418. However, the latter two sources exhibit significant increase in their pulsed X-ray intensity following the burst, while we did not detect any significant changes in the rms pulsed amplitude during the SGR 1806-20 events. Moreover, we find that the fraction of energy partitioned to the burst (prompt energy release) and the tail (afterglow) differs by an order of magnitude between SGR 1900+14 and SGR 1806-20. We suggest that such differences can be attributed to differences in the crustal heating mechanism of these neutron stars combined with the geometry of the emitting areas.

Item Type:Article
Additional Information:Article Number: 55
Uncontrolled Keywords:pulsars: individual (SGR 1806–20); X-rays: bursts
Subjects:Q Science > QB Astronomy > QB460-466 Astrophysics
Q Science > QC Physics
ID Code:17384
Deposited By:Ersin Göğüş
Deposited On:16 Nov 2011 10:58
Last Modified:08 Jan 2012 16:57

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