2009年10月 存档

拟合成功

2009年10月20日,星期二

在我画出这张图来之前,我对自己的工作不是很兴奋。原因很复杂。

但是在出来这张图之后,我有一点高兴了,毕竟是在天文上的第一个工作。虽然是拟合,但是依然高兴。

untitled

Testing Standard Cosmology with Large Scale Structure

2009年10月13日,星期二

http://astronomy.lamost.org/bbs/viewthread.php?tid=21&extra=

The galaxy power spectrum contains information on the growth of structure, the growth rate through redshift space distortions, and the cosmic expansion through baryon acoustic oscillation features.

We study the ability of two proposed experiments, BigBOSS and JDEM-PS,

科学预研究典范!

理论和观测联系:dimensionless growth rate f

数据分析工具: Fisher matrix

sparked my dig into this issue

2009年10月13日,星期二

sparked my dig into this issue

椭圆星系

2009年10月13日,星期二

一篇关于椭圆星系的博文。http://sarahaskew.net/2009/10/03/puffing-up-elliptical-galaxies/
Observational surveys of elliptical galaxies at high redshift have in recent years revealed a further interesting fact: ellipticals at high redshift appear to be much smaller in size than those in our local Universe, but have about the same mass and density of stars.

我的资源:
http://adsabs.harvard.edu/cgi-bin/nph-abs_connect?library&libname=Elliptical+Galaxy&libid=49648ac539

Lyman alpha systems and cosmology- Lyman alpha forest

2009年10月8日,星期四

http://astro.berkeley.edu/~jcohn/lya.html

1 why forest
Neutral hydrogen atoms in their lowest state will interact with whatever light has been redshifted to a wavelength of 1216 angstroms when it reaches them. The rest of the light will keep travelling to us.

2 why absorption lines

if you shine a light with wavelength 1216 at a bunch of neutral hydrogen atoms in their ground state, the atoms will absorb the light, using it to boost the electron to a higher energy state. If there are a lot of neutral hydrogen atoms in their ground state, they will absorb more and more of the light. So if you look at the light you receive, intensity as a function of wavelength, you will see a dip in the intensity at 1216 angstroms, depending on the amount of neutral hydrogen present in its ground state. The amount of light absorbed (‘optical depth’) is proportional to the probability that the hydrogen will absorb the photon (cross section) times the number of hydrogen atoms along its path.

The chemical evolution of the Galaxy

2009年10月8日,星期四

The model for the chemical evolution of the Galaxy was described in detail by Ferrini et al. (1992) and it was updated by Travaglio et al. (1999, 2001, 2004).

写作必备–没好结果的情况

2009年10月8日,星期四

It’s something to motivate calculations, not something backed up by calculations.

中国哪能没有网上天文学术论坛!

2009年10月7日,星期三

http://astronomy.lamost.org/bbs

想法由来已久,做过实验,最初被MF拒绝过,后来的一个被河马无情的抛弃了。

申请空间到现在才成功……

建站的目的首先是我自己需要。我是一个笨人,希望能站在别人的肩膀上。但是有时候连肩膀都找不到!虽然此观点被爽爽鄙视,但是我笨啊!也是对我自己的一个鞭策,我太懒了好多学习笔记问题不能及时的记下来,现在有地方了……

其次民科那么多,总不能让他们大张旗鼓的宣传我们却连个地方都没吧!

w<-1?

2009年10月7日,星期三

Today, in a seminar, a Prof. asked: in the future, if more and more the data show w=-1 with a little error bar, like today’s data most likely shows but with a bigger error, what that means? Can we rule out all the dynamical model or can still can say any thing about the nature of the DE?

which data we need more ? the data at z~1 or higher z?

“answer”:

it should be z<~1, at different bin