Magnetar Broadband X-Ray Spectra Correlated with Magnetic Fields: Suzaku Archive of SGRs and AXPs Combined with NuSTAR, Swift, and RXTE
Magnetar Broadband X-Ray Spectra Correlated with Magnetic Fields: Suzaku Archive of SGRs and AXPs Combined with NuSTAR, Swift, and RXTE
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DOI：
10.3847/1538-4365/aa6f0a
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发表时间：
2017-04
期刊：
影响因子：
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通讯作者：
T. Enoto;S. Shibata;T. Kitaguchi;Y. Suwa;T. Uchide;H. Nishioka;S. Kisaka;T. Nakano;Hiroaki Murakami;K. Makishima
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文献类型：
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作者：
T. Enoto;S. Shibata;T. Kitaguchi;Y. Suwa;T. Uchide;H. Nishioka;S. Kisaka;T. Nakano;Hiroaki Murakami;K. Makishima
作为完整的样本，研究了2006-2013年间用Suzaku观测到的15颗磁星的1-70keV持久谱。结合早期对4个硬X射线发射体的观测，9个天体在∼1-ERG S−1 cm−2的15-60keV通量下表现出以KEV为主的硬X射线发射。相对于软热表面辐射，硬X射线光度向年轻和强磁化的天体趋于高。它们的硬度比从先前的研究中更新并定义为，与测量的自旋下降速率AS相关，分别对应于与偶极场强()和特征年龄()的正相关和负相关。在我们的样本中，观察到了5个X射线爆发期间的瞬变，并将其结果与SWIFT/XRT和RXTE/PCA监测到的1-10keV的长期磁通衰变进行了比较。三次亮爆发的衰减曲线用地震学中使用的经验公式来近似，显示出∼10-40天的平台期。瞬变显示了∼1035erg S−1的最大亮度，与持久亮的亮度相当，并逐渐衰减到≲1032erg S−1。光谱性质在磁星假说的框架下进行了讨论。
The 1–70 keV persistent spectra of 15 magnetars, observed with Suzaku from 2006 to 2013, were studied as a complete sample. Combined with early NuSTAR observations of four hard X-ray emitters, nine objects showed a hard power-law emission dominating at keV with the 15–60 keV flux of ∼1– erg s−1 cm−2. The hard X-ray luminosity , relative to that of a soft-thermal surface radiation , tends to become higher toward younger and strongly magnetized objects. Their hardness ratio, updated from a previous study and defined as , is correlated with the measured spin-down rate as , corresponding to positive and negative correlations with the dipole field strength ( ) and the characteristic age ( ), respectively. Among our sample, five transients were observed during X-ray outbursts, and the results are compared with their long-term 1–10 keV flux decays monitored with Swift/XRT and RXTE/PCA. Fading curves of three bright outbursts are approximated by an empirical formula used in the seismology, showing a ∼10–40 day plateau phase. Transients show the maximum luminosities of ∼ 1035 erg s−1, which are comparable to those of persistently bright ones, and fade back to ≲1032 erg s−1. Spectral properties are discussed in the framework of the magnetar hypothesis.