期刊
ASTROPHYSICAL JOURNAL
卷 740, 期 2, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/740/2/105
关键词
pulsars: individual (SGR 0418+5729); stars: magnetic field; stars: neutron
资金
- Ramon y Cajal Fellowship
- Autonomous Region of Sardinia [FSE 2007-2013, L.R. 7/2007]
- [AAE I/088/06/0]
- [AYA 2010-21097-C03-02]
- [GVPROMETE-02009-103]
- [AYA2009-07391]
- [SGR2009-811]
- [TW2010005]
- STFC [ST/H00260X/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/H00260X/1] Funding Source: researchfish
SGR0418+5729 is a transient soft gamma-ray repeater which underwent a major outburst in 2009 June, during which the emission of short bursts was observed. Its properties appeared quite typical of other sources of the same class until long-term X-ray monitoring failed to detect any period derivative. The present upper limit on (P) over dot implies that the surface dipole field is B-p less than or similar to 7.5 x 10(12) G, well below those measured in other soft gamma-ray repeaters (SGRs) and in the Anomalous X-ray Pulsars (AXPs), a group of similar sources. Both SGRs and AXPs are currently believed to be powered by ultra-magnetized neutron stars (magnetars, B-p approximate to 10(14)-10(15) G). SGR 0418+5729 hardly seems to fit in such a picture. We show that the magneto-rotational properties of SGR 0418+5729 can be reproduced if this is an aged magnetar, approximate to 1 Myr old, which experienced substantial field decay. The large initial toroidal component of the internal field required to match the observed properties of SGR 0418+5729 ensures that crustal fractures, and hence bursting activity, can still occur at the present time. The thermal spectrum observed during the outburst decay is compatible with the predictions of a resonant Compton scattering model (as in other SGRs/AXPs) if the field is low and the magnetospheric twist is moderate.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据