Direct determination of expansion history using redshift distortions

[Chronos]

Cosmological redshift is often targeted by crackpot physics zealots. Here is a sober discussion worthy of review: Direct Determination of Expansion History Using Redshift Distortions, http://arxiv.org/abs/1210.6596

 

[Drakkith]

I can't say I understand it, but I'm glad someone wrote it lol.

 

[Lino]

Chronos, I don't pretend to understand the content, but could I ask:
1. "CAMB output" is mentioned (page 5) but I'm not familliar with this group / experiment. What is CAMB (or what does it stand for)?
2. There are a number of references to "floating measures", but again I am not familliar with this phrase. What does it mean?Regards,

Noel.

 

[Chronos]

CAMP, Code for Anisotropies in the Microwave Background, is a computer code for modeling cosmological parameters and handy for things like power spectrum analyses and lensing surveys. It is maintained by various institutions, including NASA. Floating measures are used to plot parameters like distance and power spectra without tweaking the data to fit any particular cosmological model.

 

[Lino]

Thanks Chronos. In relation to floating measures, does it equate to an input value +/- a variance to check / confirm the impact of uncertainity?

Regards,

Noel.

 

[Chronos]

That's not the purpose of floating measures, Lino. The variance between fitted and floating measures is the what the author is trying to quantify.

 

[zonde]

Cosmological redshift is often targeted by crackpot physics zealots.

I believe it's cosmological expansion not cosmological redshift that is often targeted by crackpots.

Here is a sober discussion worthy of review: Direct Determination of Expansion History Using Redshift Distortions, http://arxiv.org/abs/1210.6596

As I see this article has little to do with your implication that it tests cosmological expansion. Nonetheless it is rather interesting as it tries to give alternative method how to get parameters for accelerated expansion.

If I understand it correctly it proposes to measure expansion history (acceleration history) by means of galaxy density. Do you see it the same way?

Did it cover sample selection and population evolution (galactic mergers) questions? I didn't noticed. But then I didn't read it all.

 

[Chronos]

I believe you are correct, it is an effort to quantify expansion history and attempts to minimize the influence of 'a priori' assumptions.

 

[Lino]

That's not the purpose of floating measures, Lino. The variance between fitted and floating measures is the what the author is trying to quantify.

Thanks Chronos.

Regards,

Noel.