The first outburst of the new magnetar candidate SGR 0501+4516
The first outburst of the new magnetar candidate SGR 0501+4516
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DOI：
10.1111/j.1365-2966.2009.14920.x
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发表时间：
2009-04
影响因子：
4.8
通讯作者：
N. Rea;G. Israel;R. Turolla;P. Esposito;S. Mereghetti;D. Gotz;S. Zane;A. Tiengo;K. Hurley
中科院分区：
文献类型：
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作者：
N. Rea;G. Israel;R. Turolla;P. Esposito;S. Mereghetti;D. Gotz;S. Zane;A. Tiengo;K. Hurley
本文报道了新的软伽马射线中继器SGR0501+4516的爆发和演化。我们用XMM-牛顿从2008年8月23日开始监测新的SGR，也就是震源突然活跃后的一天，并在接下来的一个月里继续进行了四次观测，最后一次是在2008年9月30日。结合SWIFT X射线望远镜(SWIFT-XRT)和Suzaku资料，我们模拟了3个月的爆发衰减，发现源通量随时间尺度t(C)=23.8d呈指数下降。在第一次XMM-牛顿观测中，观测到了大量的短X射线爆发，并在随后的观测中急剧衰减。我们发现，在爆发衰变的第一个月中，源的光谱和时间行为发生了很大的变化，随着通量的衰减，发射变软，非热软X射线谱分量的衰减速度快于热X射线谱分量。几乎在我们第二次和第四次XMM-牛顿观测(2008年8月29日和9月2日)的同时，我们用积分观测了硬X射线范围内的源，它在第一次指向时清楚地探测到了类似于100keV的源，而在第二次指向时只给出了上限，发现在爆发激活后不到10天内，一个可变的硬X射线分量消失了。从爆发激活开始，我们进行了约160d的位相相干X射线计时分析，发现了一个很强的二阶导数周期分量[(SIC)=-1.6(4)x 10(-19)S S(-2)]。多亏了位相关联，我们能够非常详细地研究SGR0501+4516的相分辨光谱演化。我们还报告了1992年获取的ROSAT静态源数据，当时该源的流量比爆发期间测量的流量低80倍，而且热谱相当软。
We report here on the outburst onset and evolution of the new soft gamma-ray repeater SGR 0501+4516. We monitored the new SGR with XMM- Newton starting on 2008 August 23, 1 day after the source became burst active, and continuing with four more observations in the following month, with the last one on 2008 September 30. Combining the data with the Swift X-ray telescope (Swift-XRT) and Suzaku data, we modelled the outburst decay over a 3-month period, and we found that the source flux decreased exponentially with a time-scale of t(c) = 23.8 d. In the first XMM-Newton observation, a large number of short X-ray bursts were observed, the rate of which decayed drastically in the following observations. We found large changes in the spectral and timing behaviour of the source during the first month of the outburst decay, with softening emission as the flux decayed, and the non-thermal soft X-ray spectral component fading faster than the thermal one. Almost simultaneously to our second and fourth XMM-Newton observations (on 2008 August 29 and September 2), we observed the source in the hard X-ray range with INTEGRAL, which clearly detected the source up to similar to 100 keV in the first pointing, while giving only upper limits during the second pointing, discovering a variable hard X-ray component fading in less than 10 days after the bursting activation. We performed a phase-coherent X-ray timing analysis over about 160 days starting with the burst activation and found evidence of a strong second derivative period component [(sic) = -1.6(4) x 10(-19) s s(-2)]. Thanks to the phase connection, we were able to study the phase-resolved spectral evolution of SGR 0501+ 4516 in great detail. We also report on the ROSAT quiescent source data, taken back in 1992 when the source exhibits a flux similar to 80 times lower than that measured during the outburst, and a rather soft, thermal spectrum.