Max Tegmark's library: galpower

Figure 1: Proposed data analysis pipeline
You can get the 3MB uncompressed postscript file by clicking here. Click here if you are interested in other research of mine.

Measuring the galaxy power spectrum with future redshift surveys


Max Tegmark, Andrew Hamilton, Michael Strauss, Michael Vogeley, Alexander Szalay


Precision measurements of the galaxy power spectrum P(k) require a data analysis pipeline that is both fast enough to be computationally feasible and accurate enough to take full advantage of high-quality data. We present a rigorous discussion of different methods of power spectrum estimation, with emphasis on traditional, Karhunen-Loeve (KL), and quadratic schemes, showing in what approximations they give the same result. To improve speed, we show how many of the advantages of KL power spectrum estimation may be achieved with a computationally faster quadratic method. To improve accuracy, we derive analytic expressions for handling the integral constraint, since it is crucial that finite volume effects are accurately corrected for on scales comparable to the depth of the survey. We also show that for the KL and quadratic techniques, multiple constraints can be included via simple matrix operations, thereby rendering the results less sensitive to galactic extinction and misestimates of the radial selection function. We present a data analysis pipeline that we argue does justice to the increases in both quality and quantity of data that upcoming redshift surveys will provide. It involves using three analysis techniques in conjunction: a traditional Fourier approach on small scales, a pixelized quadratic matrix method on large scales and a pixelized KL eigenmode analysis to probe anisotropic effects such as redshift-space distortions.

Reference info:

ApJ, 499, 526-532 (1998), astro-ph/9709058

Online references:

This site also contains the latest (non-astro/ph) versions of some papers that are referenced in the text; Bond, Efstathiou & Tegmark 1997, Tegmark 1995, Tegmark 1997a, Tegmark 1997b, Tegmark 1997c, Tegmark & Bromley 1995, Tegmark & Hamilton 1997, Tegmark, Taylor & Heavens 1997. 

Return to my home page
This page was last modified July 1, 1998.