The Giant Flare of 1998 August 27 from SGR 1900+14. I. An Interpretive Study of<i>BeppoSAX</i>and<i>Ulysses</i>Observations

Feroci, M.; Hurley, K.; Duncan, Robert C.; Thompson, Christopher

doi:10.1086/319441

Cited by 127 publications

(191 citation statements)

References 54 publications

(52 reference statements)

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“…Furthermore, the 2-5/5-10 keV pulsed amplitude softness ratio of SGR 1900+14 (a coarse measurement of the spectrum within 2-10 keV) during this tail was found to show only modest ($25%) variations (Gö gü ş et al 2002). To estimate the X-ray energy in the tail of the August 27 flare, we integrated a power-law fit to the pulsed flux measurements in the 2-10 keV band between the end of the burst as observed in gamma rays (Feroci et al 2001) and 40 days following the flare minus the persistent emission flux over the same time interval. We measure a tail fluence of 1:5 Â 10 À4 ergs cm À2 or an isotropic energy of 3:5 Â 10 42 d 2 14 kpc ergs.…”

Section: Burst Comparisonmentioning

confidence: 99%

“…In contrast to these common brief bursts, two SGRs have each emitted one large long-duration burst. These large bursts, or '' giant flares '' as they are sometimes called, are distinguished by their extreme energies ($10 44 ergs), their hard spectra at the onset, and their coherent pulsations during the decaying tail (lasting several minutes), reflecting the spin of the underlying neutron star (Mazets et al 1979;Hurley et al 1999a;Feroci et al 2001).…”

Section: Introductionmentioning

confidence: 99%

“…In this paper we focus on SGR 1900+14, which has been the most prolific SGR in the last 3 yr. SGR 1900+14 is the source of one of the giant flares that was recorded on 1998 August 27 (Hurley et al 1999a;Mazets et al 1999;Feroci et al 1999Feroci et al , 2001. Following the flare, the persistent X-ray flux of SGR 1900+14 increased dramatically and decayed over the next $40 days as a power law in time with an index of $À0.7 .…”

Section: Introductionmentioning

confidence: 99%

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

Lenters

Woods

Goupell

et al. 2003

ApJ

114

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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.

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Section: Burst Comparisonmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Lenters

Woods

Goupell

et al. 2003

ApJ

114

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“…Several lines of evidence, both observational and theoretical as described by Arons (1993), indicate that nondipolar (quadrupolar, octopolar, ...) components in pulsars have to be smaller than the dipolar one. On the other hand, the fourpeaked shape of the light curve of the giant flare of August 27, 1998 from SGR 1900+14 (Feroci et al 2001) is probably strong evidence for the presence of a large quadrupolar component in this magnetar.…”

Section: Introductionmentioning

confidence: 96%

Temperature distribution in magnetized neutron star crusts

Geppert¹,

Kueker²,

Page³

2004

A&A

123

150

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Abstract. We investigate the influence of different magnetic field configurations on the temperature distribution in neutron star crusts. We consider axisymmetric dipolar fields which are either restricted to the stellar crust, "crustal fields", or allowed to penetrate the core, "core fields". By integrating the two-dimensional heat transport equation in the crust, taking into account the classical (Larmor) anisotropy of the heat conductivity, we obtain the crustal temperature distribution, assuming an isothermal core. Including classical and quantum magnetic field effects in the envelope as a boundary condition, we deduce the corresponding surface temperature distributions. We find that core fields result in practically isothermal crusts unless the surface field strength is well above 10 15 G while for crustal fields with surface strength above a few times 10 12 G significant deviations from crustal isothermality occur at core temperatures inferior or equal to 10 8 K. At the stellar surface, the cold equatorial region produced by the suppression of heat transport perpendicular to the field by the Larmor rotation of the electrons in the envelope, present for both core and crustal fields, is significantly extended by that classical suppression at higher densities in the case of crustal fields. This can result, for crustal fields, in two small warm polar regions which will have observational consequences: the neutron star has a small effective thermally emitting area and the X-ray pulse profiles are expected to have a distinctively different shape compared to the case of a neutron star with a core field. These features, when compared with X-ray data on thermal emission of young cooling neutron stars, would provide a first step toward a new way of studying the magnetic flux distribution within a neutron star.

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“…Within this time span, SGR 1900+14 entered several burst active episodes; the most notable of which was the outburst that began on 1998 August 27 with a giant flare having a total energy ∼10 44 ergs (e.g. Feroci et al 2001). Coincident with this giant flare was a large increase in the persistent and pulsed flux from the source (e.g.…”

Section: Comparison To Sgr Outbursts: X-ray Flux and Spectrummentioning

confidence: 99%

Changes in the X-ray Emission from the Magnetar Candidate 1E 2259+586 during its 2002 Outburst

Woods

Kaspi

Thompson

et al. 2004

AIP Conference Proceedings

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An outburst of more than 80 individual bursts, similar to those seen from Soft Gamma Repeaters (SGRs), was detected from the Anomalous X-ray Pulsar (AXP) 1E 2259+586 in 2002 June. Coincident with this burst activity were gross changes in the pulsed flux, persistent flux, energy spectrum, pulse profile and spin down of the underlying X-ray source. We present Rossi X-ray Timing Explorer and X-ray Multi-Mirror Mission observations of 1E 2259+586 that show the evolution of the aforementioned source parameters during and following this episode and identify recovery time scales for each. Specifically, we observe an X-ray flux increase (pulsed and phase-averaged) by more than an order of magnitude having two distinct components. The first component is linked to the burst activity and decays within ∼2 days during which the energy spectrum is considerably harder than during the quiescent state of the source. The second component decays over the year following the glitch according to a power law in time with an exponent −0.22 ± 0.01. The pulsed fraction decreased initially to ∼15% RMS, but recovered rapidly to the pre-outburst level of ∼23% within the first three days. The pulse profile changed significantly during the outburst, and recovered almost fully within two months of the outburst. A glitch of size ∆ν max /ν = (4.24 ± 0.11) × 10 −6 was observed in 1E 2259+586 that preceded the observed burst activity. The glitch could not be well fit with a simple partial exponential recovery. An exponential rise of ∼20% of the frequency jump with a time scale of ∼14 days results in a significantly better fit to the data, however contamination from a systematic drift in the phase of the pulse profile cannot be -2 -excluded. A fraction of the glitch (∼19%) recovered in a quasi-exponential manner having a recovery time scale of ∼16 days. The long-term post-glitch spin-down rate decreased in magnitude relative to the pre-glitch value. The changes in the source properties of 1E 2259+586 during its 2002 outburst are shown to be qualitatively similar to changes seen during/following burst activity in two SGRs, thus further solidifying the common nature of SGRs and AXPs as magnetars. The changes in persistent emission properties of 1E 2259+586 suggest that the star underwent a plastic deformation of the crust that simultaneously impacted the superfluid interior (crustal and possibly core superfluid) and the magnetosphere. Finally, the changes in persistent emission properties coincident with burst activity in 1E 2259+586 enabled us to infer previous burst active episodes from this and other AXPs. The non-detection of these outbursts by all-sky gamma-ray instruments suggests that the number of active magnetar candidates in our Galaxy is larger than previously thought.

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The Giant Flare of 1998 August 27 from SGR 1900+14. I. An Interpretive Study ofBeppoSAXandUlyssesObservations

Cited by 127 publications

References 54 publications

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

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

Temperature distribution in magnetized neutron star crusts

Changes in the X-ray Emission from the Magnetar Candidate 1E 2259+586 during its 2002 Outburst

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