THE EFFECT OF NOISE ON THE DUST TEMPERATURE–SPECTRAL INDEX CORRELATION
THE EFFECT OF NOISE ON THE DUST TEMPERATURE–SPECTRAL INDEX CORRELATION
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DOI：
10.1088/0004-637x/696/1/676
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发表时间：
2009-02
期刊：
影响因子：
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通讯作者：
R. Shetty;J. Kauffmann;S. Schnee;A. Goodman
中科院分区：
文献类型：
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作者：
R. Shetty;J. Kauffmann;S. Schnee;A. Goodman
我们研究如何在通量测量的不确定性影响的结果，从修改黑体光谱能量分布（SED）适合。我们表明，尘埃温度T和光谱指数β之间的负相关性自然会产生最小二乘拟合由于不确定性，即使是一个单一的T和β源。仅在Rayleigh-Jeans制度中将SED拟合到噪声通量会产生不可靠的T和β估计。因此，对于长波长观测（λ <$200 μm）或暖源（T <$60 K），很难区分不同温度的源。我们评估了噪声在最近的观测结果中的作用，这些结果表明T-β关系是逆的和连续变化的。虽然逆的和连续的T-β相关可能是星际介质中尘埃的一种物理性质，但我们发现，观测到的逆相关可能主要是由于噪声。
We investigate how uncertainties in flux measurements affect the results from modified blackbody spectral energy distribution (SED) fits. We show that an inverse correlation between the dust temperature T and spectral index β naturally arises from least-squares fits due to the uncertainties, even for sources with a single T and β. Fitting SEDs to noisy fluxes solely in the Rayleigh–Jeans regime produces unreliable T and β estimates. Thus, for long wavelength observations (λ ≳ 200 μm), or for warm sources (T ≳ 60 K), it becomes difficult to distinguish sources with different temperatures. We assess the role of noise in recent observational results that indicate an inverse and continuously varying T–β relation. Though an inverse and continuous T–β correlation may be a physical property of dust in the interstellar medium, we find that the observed inverse correlation may be primarily due to noise.