BeppoSAX Observations of the Young Pulsar in the Kes 75 Supernova Remnant
BeppoSAX Observations of the Young Pulsar in the Kes 75 Supernova Remnant
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DOI：
10.1086/340976
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发表时间：
2002-08
期刊：
影响因子：
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通讯作者：
S. Mereghetti;R. Bandiera;F. Bocchino;G. Israel
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文献类型：
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作者：
S. Mereghetti;R. Bandiera;F. Bocchino;G. Israel
我们提出的年轻的X射线脉冲星PSR J1846-0258，最近在复合超新星遗迹Kes 75的中心发现的BeppoSAX观测的结果。脉冲星（加星云）光谱符合吸收功率定律，光子指数αph = 2.16 ± 0.15，NH =（4.7 ± 0.8）× 1022 cm-2，未吸收通量~3.9 × 10-11 ergscm-2s-1（2-10 keV）。通过将间隔2周的两次观察结果结合起来，我们已经能够获得自旋周期的精确测量值（P = 324.818968 ± 0.000006 ms）。当与先前的测量值结合时，该值不能通过具有规范制动指数n = 3的平滑频率演变来拟合。假设没有毛刺和/或明显的计时噪声，则制动指数为n = 1.86 ± 0.08，假设初始周期较短，则脉冲星的年龄约为1700年，比简单估计的τ = P/2 = 723年更接近超新星遗迹的年龄。其他可能的可能性包括小故障的存在，并导致广泛的可接受的年龄范围。例如，如果故障发生在MJD 51500附近，我们得到的n在1.8-2.5的范围内，而对于1993年10月至1999年3月之间的故障，我们只能得到n > 1.89的下限。
We present the results of BeppoSAX observations of the young X-ray pulsar PSR J1846-0258, recently discovered at the center of the composite supernova remnant Kes 75. The pulsar (plus nebula) spectrum can be fitted by an absorbed power law with photon index αph = 2.16 ± 0.15, NH = (4.7 ± 0.8) × 1022 cm-2, and unabsorbed flux ~3.9 × 10-11 ergs cm-2 s-1 (2-10 keV). By joining two observations taken at an interval of 2 weeks, we have been able to obtain a precise measurement of the spin period (P = 324.818968 ± 0.000006 ms). This value, when combined with previous measurements, cannot be fitted by a smooth frequency evolution with a canonical braking index n = 3. With the hypothesis of no glitches and/or significant timing noise, the braking index would be n = 1.86 ± 0.08, and assuming a short initial period, the pulsar age would be ~1700 yr, closer to that of the supernova remnant than the simple estimate τ = P/2 = 723 yr. Other likely possibilities involve the presence of glitches and lead to a wide range of acceptable ages. For example, we obtain n in the range 1.8-2.5 if a glitch occurred near MJD 51500, while for a glitch between 1993 October and 1999 March, we can only get a lower limit of n > 1.89.