PROPERTIES AND SPATIAL DISTRIBUTION OF DUST EMISSION IN THE CRAB NEBULA
PROPERTIES AND SPATIAL DISTRIBUTION OF DUST EMISSION IN THE CRAB NEBULA
复制标题
蟹状星云尘埃排放的特性和空间分布
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
T. Roellig
中科院分区：
文献类型：
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作者：
T. Temim;G. Sonneborn;E. Dwek;R. Arendt;R. Gehrz;P. Slane;T. Roellig
最近对超新星遗迹中新形成的尘埃进行的红外(IR)观测，产生的尘埃质量明显低于理论模型预测的尘埃质量，并通过高红移观测进行了测量。蟹状星云的脉冲星风被认为正在席卷新形成的超新星(SN)尘埃和喷出的气体。这种尘埃的证据是在蟹状星云的综合光谱中发现的红外过剩，以及在同步加速器星云的消光中发现的，这揭示了细丝核心中存在尘埃。我们介绍了用斯皮策太空望远镜上的红外光谱仪获得的蟹状星云中尘埃的第一个空间分辨发射光谱。红外光谱以同步辐射为主，表现为S、Si、Ne、Ar、O、Fe和Ni的禁用线发射。我们从3.6和4.5 μm的图像中得到了同步加速器光谱图，并从我们的数据中减去了这一贡献，得到了尘埃剩余连续发射的图。粉尘排放似乎集中在喷出的细丝上，并由无定形碳或硅酸盐颗粒组成很好地描述。发现硅酸盐的尘埃温度为55±4K，碳粒的尘埃温度为60±7K。总的尘埃质量估计为(1.2-12)×10−3 M☉，远低于对核心塌缩超新星的理论尘埃量预测。我们的颗粒加热模型表明，尘埃颗粒半径相对较小，与IIP SN类型中形成的尘埃颗粒的预期不同。
Recent infrared (IR) observations of freshly formed dust in supernova remnants have yielded significantly lower dust masses than predicted by theoretical models and measured from high-redshift observations. The Crab Nebula's pulsar wind is thought to be sweeping up freshly formed supernova (SN) dust along with the ejected gas. The evidence for this dust was found in the form of an IR excess in the integrated spectrum of the Crab and in extinction against the synchrotron nebula that revealed the presence of dust in the filament cores. We present the first spatially resolved emission spectra of dust in the Crab Nebula acquired with the Infrared Spectrograph on board the Spitzer Space Telescope. The IR spectra are dominated by synchrotron emission and show forbidden line emission from S, Si, Ne, Ar, O, Fe, and Ni. We derived a synchrotron spectral map from the 3.6 and 4.5 μm images, and subtracted this contribution from our data to produce a map of the residual continuum emission from dust. The dust emission appears to be concentrated along the ejecta filaments and is well described by an amorphous carbon or silicate grain compositions. We find a dust temperature of 55 ± 4 K for silicates and 60 ± 7 K for carbon grains. The total estimated dust mass is (1.2–12) × 10−3 M☉, well below the theoretical dust yield predicted for a core-collapse supernova. Our grain heating model implies that the dust grain radii are relatively small, unlike what is expected for dust grains formed in a Type IIP SN.