# 关于冷尘埃SED程序的一些笔记

(这里有一些理论公式推导：http://eagle.lamost.org/?p=37798 ，比此文更加详细，可以参看)

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1. 什么叫相对误差？我觉得一般表示参数的后验概率不是用的“相对误差”这个概念……

1. 我还没有考虑那么多。这个不是严格的“相对误差”，是norm(x’/x-1)的值。

2. The extinction efficiency is called in , which is not right.
The macroscopic emission coefficient or , in local thermodynamic equilibrium, is
given by Kirchhoff-Planck relation:

1. directus says:

Then what are you trying to say

2. directus says:

维基百科里说：“The emissivity of a material (usually written ε or e) is the relative ability of its surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. A true black body would have an ε = 1 while any real object would have ε < 1. Emissivity is a dimensionless quantity.” 我怀疑严格的物理定义里面，emissivity是没有量纲的量，而天文里面为了吧emission coefficient简称，所以才那么叫。

3. , in local thermodynamic equilibrium, is
given by Kirchhoff-Planck relation:
,

1. 至少，物理上 emissty 的定义不是Hildebrand1983 所说的。天文上物理量的名称都是自己想咋说咋说。。。

1. directus says:

不同意。

1. An introduction to radiative transfer: methods and applications in astrophysics 第11页。
The physics and chemistry of the interstellar medium
公式5.32

2. 在 Rybicki 和 Lightman 合著的 Radiative Process in Astrophysics 教材的第九页，上面清楚的写了：emission coefficient 是你说的那个j.并且国内的教材也叫J发射系数。

4. Emissivity then, is a fractional representation of the amount of energy from some material vs. the
energy that would come from a blackbody at the same temperature.

这里说的已经很显然了。
tes.asu.edu/MARS_SURVEYOR/MGSTES/TES_emissivity.html

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