An Extended Burst Tail from SGR 1900+14 with a Thermal X‐Ray Spectrum

The soft gamma repeater SGR 1900+14 entered a new phase of activity in 2001 April initiated by the intermediate flare recorded on April 18. Ten days following this flare, we discovered an abrupt increase in the source flux between consecutive Rossi X-Ray Timing Explorer (RXTE) orbits. This X-ray flux excess decayed over the next several minutes and was subsequently linked to a high fluence burst from SGR 1900+14 recorded by other spacecraft (Ulysses and Wind/Konus) while the SGR was Earth-occulted for RXTE. We present here spectral and temporal analysis of both the burst of April 28 and the long X-ray tail following it. We find strong evidence of an exclusively thermal X-ray tail in this event and bring this evidence to bear on other bursts and flares from SGR 1900+14 that have shown extended X-ray excesses (e.g., 1998 August 29). We include in this comparison a discussion of the physical origins of SGR bursts and extended X-ray tails.

[1]  C. Kouveliotou,et al.  Temporal and Spectral Characteristics of Short Bursts from the Soft Gamma Repeaters 1806–20 and 1900+14 , 2001, astro-ph/0105110.

[2]  S. Barthelmy,et al.  A giant periodic flare from the soft γ-ray repeater SGR1900+14 , 1998, Nature.

[3]  C. Kouveliotou,et al.  Multiwavelength Observations of the Soft Gamma Repeater SGR 1900+14 during Its 2001 April Activation , 2001, astro-ph/0107170.

[4]  C. Kouveliotou,et al.  Physical mechanisms for the variable spin-down and light curve of SGR 1900+14 , 1999, astro-ph/9908086.

[5]  Radio Emission from Magnetars , 2002, astro-ph/0206439.

[6]  C. Kouveliotou,et al.  BEPPOSAX Observations of SGR 1900+14 in Quiescence and during an Active Period , 1999 .

[7]  Christopher Thompson,et al.  Formation of very strongly magnetized neutron stars - Implications for gamma-ray bursts , 1992 .

[8]  K. Hurley,et al.  An X-ray pulsar with a superstrong magnetic field in the soft γ-ray repeater SGR1806 − 20 , 1998, Nature.

[9]  S. R. Kulkarni,et al.  Electrodynamics of Magnetars: Implications for the Persistent X-Ray Emission and Spin-down of the Soft Gamma Repeaters and Anomalous X-Ray Pulsars , 2001, astro-ph/0110677.

[10]  C. Kouveliotou,et al.  A Comprehensive Study of Pulse Profile Evolution in SGR 1806–20 and SGR 1900+14 with the Rossi X-Ray Timing Explorer Proportional Counter Array , 2002 .

[11]  Hubble Space Telescope Observations of SGR 0526–66: New Constraints on Accretion and Magnetar Models , 2001, astro-ph/0103179.

[12]  J. R. Houck,et al.  Possible Infrared Counterparts to the Soft Gamma-Ray Repeater SGR 1806–20 , 2001, astro-ph/0110619.

[13]  C. Kouveliotou,et al.  Variable Spin-Down in the Soft Gamma Repeater SGR 1900+14 and Correlations with Burst Activity , 1999, astro-ph/9907173.

[14]  C. Kouveliotou,et al.  Evidence for a Sudden Magnetic Field Reconfiguration in Soft Gamma Repeater 1900+14 , 2001, astro-ph/0101045.

[15]  N. White,et al.  Correlations between Spectral Properties and Spin-down Rate in Soft Gamma-Ray Repeaters and Anomalous X-Ray Pulsars , 2001, astro-ph/0102375.

[16]  Tod Strohmayer,et al.  Discovery of a Magnetar Associated with the Soft Gamma Repeater SGR 1900+14 , 1998, astro-ph/9809140.

[17]  M. Feroci,et al.  The Giant Flare of 1998 August 27 from SGR 1900+14. I. An Interpretive Study of BeppoSAX and Ulysses Observations , 2000, astro-ph/0010494.

[18]  B. Paczyński.  GB 790305 as a very strongly magnetized neutron star , 1992 .

[19]  S. V. Golenetskii,et al.  Observations of a flaring X-ray pulsar in Dorado , 1979, Nature.

[20]  Vrba,et al.  The Discovery of an Embedded Cluster of High-Mass Stars near SGR 1900+14 , 2000, The Astrophysical journal.

[21]  Tod E. Strohmayer,et al.  An Unusual Burst from Soft Gamma Repeater SGR 1900+14: Comparisons with Giant Flares and Implications for the Magnetar Model , 2000, astro-ph/0007043.

[22]  D. Eichler,et al.  Diagnosing Magnetars with Transient Cooling , 2002, astro-ph/0211110.

[23]  C. Thompson,et al.  The soft gamma repeaters as very strongly magnetized neutron stars - I. Radiative mechanism for outbursts , 1995 .

[24]  Christopher Thompson,et al.  The Soft Gamma Repeaters as Very Strongly Magnetized Neutron Stars. II. Quiescent Neutrino, X-Ray, and Alfvén Wave Emission , 1996 .