3XMM J185246.6+003317: ANOTHER LOW MAGNETIC FIELD MAGNETAR
3XMM J185246.6+003317: ANOTHER LOW MAGNETIC FIELD MAGNETAR
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DOI：
10.1088/2041-8205/781/1/l17
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发表时间：
2013-11
期刊：
影响因子：
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通讯作者：
N. Rea;D. Viganò;G. Israel;J. Pons;D. Torres
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文献类型：
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作者：
N. Rea;D. Viganò;G. Israel;J. Pons;D. Torres
我们研究了新发现的X射线瞬变3XMM J185246.6+003317的爆发，重新分析了所有可用的XMM-牛顿观测，进行了相位相干定时分析，并得出了更新的周期和周期导数值。我们发现震源在P=11.55871346(6)S(90%置信度；历元MJD 54728.7)处旋转，但没有证据表明在观测所跨越的7个月的突出衰减中存在周期导数。这意味着S S−1的周期导数的上限为3σ，假设经典的磁偶极制动模型，给出了BDIP<；4.1×1013 G的偶极磁场的上限。3XMM J185246.6+003317的X射线爆发和光谱特征证实了它是磁星，但我们导出的磁场上限将它定义为继SGR0418+5729和SWIFT J1822.3−1606之后在过去3年中发现的第三颗“低B”磁星。我们还得到了静止光度的上限(<；4×1033erg S−1)，与对旧磁星的期望一致。这颗新的低场磁星的发现证实了一种预测，即在隐藏的老年磁星群体中，每年大约会有一次爆发。
We study the outburst of the newly discovered X-ray transient 3XMM J185246.6+003317, re-analyzing all available XMM-Newton observations of the source to perform a phase-coherent timing analysis, and derive updated values of the period and period derivative. We find the source rotating at P = 11.55871346(6) s (90% confidence level; at epoch MJD 54728.7) but no evidence for a period derivative in the seven months of outburst decay spanned by the observations. This translates to a 3σ upper limit for the period derivative of s s−1, which, assuming the classical magneto-dipolar braking model, gives a limit on the dipolar magnetic field of Bdip < 4.1 × 1013 G. The X-ray outburst and spectral characteristics of 3XMM J185246.6+003317 confirm its identification as a magnetar, but the magnetic field upper limit we derive defines it as the third “low-B” magnetar discovered in the past 3 yr, after SGR 0418+5729 and Swift J1822.3−1606. We have also obtained an upper limit to the quiescent luminosity (<4 × 1033 erg s−1), in line with the expectations for an old magnetar. The discovery of this new low field magnetar reaffirms the prediction of about one outburst per year from the hidden population of aged magnetars.