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Data

Sloan Digital Sky Survey

Here we provide the basic resources for doing large-scale structure studies with data from the Sloan Digital Sky Survey. This consists of:

  • A list of galaxies representing a flux-limited sample (to maximum apparent r-band magnitude of 17.6), containing the angular position of each galaxy on the sky, its redshift, and photometric information. Details on the contents of each column are explained in README.sdss. The galaxy list here has been extracted from the latest version of the NYU-VAGC - please cite Blanton et al. if you use it.
  • The radial selection function representing the expected average comoving density of galaxies as a function of comoving radial distance. The file format is explained in README.sdss. It has been derived from the redshift selection function file czselfunc.all provided by NYU-VAGC - please cite Blanton et al. if you use it.
  • The angular selection function representing the completeness of the SDSS spectroscopic survey as a function of position on the sky. This is provided as a mangle polygon file with the weight of each polygon representing the fraction of galaxies with observed redshifts in that region (weight 0 = no galaxies observed, weight 1 = 100% of galaxies observed). This file has been assembled using mangle 2.1 from the window and mask polygon files provided by NYU-VAGC with the script mangle_sdss.sh - please cite Swanson et al., Hamilton & Tegmark, and Blanton et al. if you use it.

Other useful formats for the SDSS angular selection function:

Earlier SDSS data releases - file formats and citations are the same as above.

2dF Galaxy Redshift Survey

Here we provide the basic resources for doing large-scale structure studies with data from the 2dF Galaxy Redshift Survey. The files provided here were prepared by Andrew Hamilton and constitute an improved version of the 2dFGRS official final data release, which accounts for weather-related effects, removes duplicate and poor-quality sources from the catalog, provides a uniform flux limit across the whole survey, and resolves a number of other issues. If you use these files, please cite Colless et al., this website, and Hamilton et al., in prep.

The mangle software also comes packaged with tools for creating the angular masks for the 2dfGRS official data releases, as detailed in Colless et al. (2001) and Colless et al. (2003) as well as at the 2dFGRS website. Here we provide formatted versions of the unformatted fortran data files that define the 2dFGRS angular masks. If your system has trouble with the unformatted fortran files provided with mangle, use these instead.

Approximate HEALPix Polygons

These files provide the approximate HEALPix polygons used by mangle's rasterize utility to produce files in HEALPix format. All polygon files are pixelized to simple resolution 8 and should be unpacked in the MANGLEDIR/masks/healpix/healpix_polys directory. Please cite Gorski et al. and Swanson et al. if you use them.

Similar files for Nside = 1 through 32 are distributed with the mangle source code. Approximate HEALPix polygons at any Nside can be constructed using the healpixpolys.sh script.