X-Ray Observations of the Supernova Remnant G21.5–0.9
X-Ray Observations of the Supernova Remnant G21.5–0.9
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DOI：
10.1086/322978
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发表时间：
2001-07
期刊：
影响因子：
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通讯作者：
S. Safi-Harb;I. Harrus;R. Petre;G. Pavlov;A. B. Koptsevich;D. Sanwal
中科院分区：
文献类型：
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作者：
S. Safi-Harb;I. Harrus;R. Petre;G. Pavlov;A. B. Koptsevich;D. Sanwal
我们对超新星遗迹 (SNR) G21.5-0.9 的档案 X 射线观测结果进行了分析。根据其形态和光谱特性，G21.5-0.9 被归类为类蟹 SNR。因此，它被选为钱德拉校准目标。在对部分校准数据的早期分析中，斯莱恩和同事发现表面亮度低、发射时间延长。他们将此成分解释为超新星爆炸中形成的冲击波。 Warwick 及其同事的 XMM-Newton 观测揭示了这种发射的非热性质，表明它是同步加速器星云的延伸。在本文中，我们使用新的校准数据重新审视了 Chandra 分析，将统计数据提高了 2 倍。我们还包括 ROSAT 和 ASCA 观测结果。我们的分析证实了扩展发射的非热性质。高级 CCD 成像光谱仪图像表明，该组件没有肢体增亮，并且显示出多节结构和中心以北 2 英尺处的明亮细丝。我们没有发现残余物任何部分存在线发射的证据。我们可以拒绝太阳丰度下的碰撞平衡电离热模型和非平衡电离（NEI）模型（例如具有不同电离年龄和恒定温度的平面平行激波模型或具有单一电离年龄和恒定温度的NEI模型）。整个残骸最好采用幂律模型，其中光子指数远离中心逐渐变陡。总未吸收通量 FX(0.5-10 keV) 为 1.1 × 10-10 ergs cm-2 s-1，其中 85% 来自 40'' 半径核心。高分辨率相机数据的时序分析未能检测到任何脉动。我们对脉冲分数设定了 16% 的上限。我们推导出假定的脉冲星的物理参数，并将其与其他plerion（例如蟹状星云和3C 58）的物理参数进行比较。
We present the analysis of archival X-ray observations of the supernova remnant (SNR) G21.5-0.9. Based on its morphology and spectral properties, G21.5-0.9 has been classified as a Crab-like SNR. For that reason, it was chosen as a Chandra calibration target. In their early analysis of part of these calibration data, Slane and coworkers discovered a low surface brightness, extended emission. They interpreted this component as the blast wave formed in the supernova explosion. XMM-Newton observations by Warwick and coworkers revealed the nonthermal nature of this emission, suggesting that it is instead an extension of the synchrotron nebula. In this paper, we revisit the Chandra analysis using new calibration data, improving the statistics by a factor of 2. We also include ROSAT and ASCA observations. Our analysis confirms the nonthermal nature of the extended emission. Advanced CCD Imaging Spectrometer images indicate that this component is not limb-brightened and that it shows knotty structures and a bright filament 2' north of the center. We find no evidence of line emission from any part of the remnant. We can reject a collisional equilibrium ionization thermal model at solar abundances and nonequilibrium ionization (NEI) models (such as a plane-parallel shock model with different ionization ages and constant temperature or an NEI model with a single ionization age and a constant temperature). The entire remnant is best fitted with a power-law model with a photon index steepening away from the center. The total unabsorbed flux FX(0.5-10 keV) is 1.1 × 10-10 ergs cm-2 s-1 with an 85% contribution from the 40'' radius core. Timing analysis of the High-Resolution Camera data failed to detect any pulsations. We put a 16% upper limit on the pulsed fraction. We derive the physical parameters of the putative pulsar and compare them with those of other plerions (such as the Crab nebula and 3C 58).