## Thousand square degree run

This directory contains simulated weak lensing maps made from ray tracing
through N-body simulations of structure formation. Multiple runs of the
same cosmological model, started with different random number seeds, are
used to build up 1000 square degrees of lensing sky, in (independent) 3x3
degree chunks.

#### Basic data

The basic data consists of a series of maps for our model which is of the
spatially flat Lambda CDM family with a scale-invariant initial power
spectrum. The matter density is 28% of the critical density and the baryon
density is 4.9% of critical. We assume the Hubble constant is 70km/s/Mpc
and the normalization has sigma8=0.9.
In all seven independent simulations of a 200Mpc/h cubical box were run,
each with 384^3 equal mass (~10^10Msun/h) dark matter particles. The
force softening was of the spline form with a Plummer equivalent
epsilon of 18kpc/h (constant in comoving coordinates). The full phase
space distribution was dumped every 50Mpc/h along the line-of-sight.
For each box 16 maps were produced by ray tracing with different orientations
through the lightcone produced by the series of outputs.

All of the files are in FITS format and contain arrays of two shear components
and convergences covering a 3x3 degree field of view. Each FITS file contains
the data for one field in a 3xNxN array where N=1024 pixels.

The maps have been made for 4 source redshift distributions. For simplicity
we take p(z)~z^2 Exp[-(z/z0)^b] with b=1.5 or 1.0 and =1.0 or 1.5. The
source distributions are labelled as:

- 01: Sources with <z>=1.0 and b=1.5
- 02: Sources with <z>=1.5 and b=1.5
- 03: Sources with <z>=1.0 and b=1.0
- 04: Sources with <z>=1.5 and b=1.0

To simplify downloads and file management, the maps for distribution 1 have
been grouped into (gzipped) tar files called shear.N.01.tgz where N=11-17.

#### Auxilliary data

Galaxy catalogues, containing angular and redshift position, convergence
and shear for a "realistic" source distribution, are available.
There are 7 entries per galaxy and roughly 200 galaxies per square
arcminute as explained in the FITS headers.
These galaxies are meant to be used for testing shot-noise or shear
assignment, the clustering properties are not terribly realistic.
For people interested in finding clusters, 3D group catalogues have been
produced.
The files contain the cluster information for each field.
Each group has 1 row and the columns are x and y pixel position for
the most bound particle in the group, M_{200} in Msun/h, comoving distance
in Mpc/h, line-of-sight velocity as a distance offset (also in Mpc/h),
redshift and FoF group mass.

**Beware** of array indexing conventions between C/Fortran/IDL etc.
You may need to transpose the maps to get correspondance with the files.

## Index of Lensing/Thousand

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*Last modified Thu Sep 7 07:46:20 2006*