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arXiv 0904.4377astro-ph.HEastro-ph.GA
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用费米大天区望远镜观测毫秒脉冲星J0030 +0451的脉冲γ射线

Pulsed Gamma-rays from the millisecond pulsar J0030+0451 with the Fermi Large Area Telescope

LAT Collaboration

摘要:

本文报道了用\emph{Fermi}伽玛射线空间望远镜(原GLAST)上的大视场望远镜(LAT)从附近孤立的毫秒脉冲星PSR J0030+0451中发现的伽玛射线脉动。这一发现使PSR J0030+0451成为继PSR J0218+4232之后第二颗被康普顿伽马射线天文台EGRET仪器观测到的伽马射线毫秒脉冲星。自旋下降功率$\dot E = $ 3.5 $\times$ 10 $^{33}$ ergs $^{-1}$比先前已知的伽马射线辐射的经验下限低一个数量级。发射曲线的特征在于两个窄峰,分别为0.07 $\pm$ 0.01和0.08 $\pm$ 0.02宽,由0.44 $\pm$ 0.02在相位上分开。第一个伽玛射线峰值下降0.15 $\pm$ 0.01后的主要无线电峰值。脉冲的形状类似于“正常”的伽马射线暴。发射光谱的指数截止幂律拟合导致100 MeV以上的积分光子通量为(6.76 $\pm$ 1.05 $\pm$ 1.35)$\times 10^{-8}$ cm $^{-2}$ s $^{-1}$,截止能量为(1.7 $\pm$ 0.4 $\pm$ 0.5)GeV。基于PDMATHABMU_pc的视差距离,我们得到了在各向同性辐射条件下,自旋下降能率转换为γ射线辐射的γ射线效率$L_γ/ \dot{E} \simeq 15%$。

英文摘要:

We report the discovery of gamma-ray pulsations from the nearby isolated millisecond pulsar PSR J0030+0451 with the Large Area Telescope (LAT) on the \emph{Fermi} Gamma-ray Space Telescope (formerly GLAST). This discovery makes PSR J0030+0451 the second millisecond pulsar to be detected in gamma-rays after PSR J0218+4232, observed by the EGRET instrument on the Compton Gamma Ray Observatory. The spin-down power $\dot E = $ 3.5 $\times$ 10$^{33}$ ergs s$^{-1}$ is an order of magnitude lower than the empirical lower bound of previously known gamma-ray pulsars. The emission profile is characterized by two narrow peaks, respectively 0.07 $\pm$ 0.01 and 0.08 $\pm$ 0.02 wide, separated by 0.44 $\pm$ 0.02 in phase. The first gamma-ray peak falls 0.15 $\pm$ 0.01 after the main radio peak. The pulse shape is similar to that of the "normal" gamma-ray pulsars. An exponentially cut-off power-law fit of the emission spectrum leads to an integral photon flux above 100 MeV of (6.76 $\pm$ 1.05 $\pm$ 1.35) $\times 10^{-8}$ cm$^{-2}$ s$^{-1}$ with cut-off energy (1.7 $\pm$ 0.4 $\pm$ 0.5) GeV. Based on its parallax distance of $(300 \pm 90)$ pc, we obtain a gamma-ray efficiency $L_γ/ \dot{E} \simeq 15%$ for the conversion of spin-down energy rate into gamma-ray radiation, assuming isotropic emission.

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