MAPSIM v0.1

CMB temperature anisotropy map CMB Q Stokes parameter anisotropy map CMB U Stokes parameter anisotropy map

mapsim is a set of C codes designed to generate simulted CMB temperature and polarization anisotropy maps given a set of temperature and polarization angular power spectra and pixelization. It was developed by Matthew Abroe at the University of Minnesota Supercomputing Institute, under the auspicies of the COMBAT collaboration.

Two versions of mapsim are available: One designed to run on a mulitiple processor machine using MPI, and the other on a standard single processor workstation. For the MPI version download mapsim_MPI.tar; otherwise download mapsim.tar. After downloading type:

tar xvfm mapsim.tar

make

to compile all the necessary programs. All the C source code contains comments and a description of the functions used by mapsim. There are two input files to mapsim:

the angular power spectrum file
the pixels file

1) The format for the angular power spectrum file is

for each spherical harmonic multipole
l C_l^Tl(l+1)/2pi C_l^TEl(l+1)/2pi C_l^El(l+1)/2pi C_l^Bl(l+1)/2pi
where the last four numbers have units of [K]^2

2) The format for the pixels file is

for each pixel
ra dec
given in degrees

To run type:

mapsim 'ps file name' 'pixel file name'

The output file is called map.dat. The format for map.dat is

for each pixel
T Q U
given in units of [micro K]^2

Included are sample input files which were used to generate the maps at the top of this page. They are called ps and pixels. The pixels file contains 65,536 square pixels at a resolution of 3'. The ps file contains the power spectra for the best fit inflationary model to the MAXIMA-1 and COBE DMR data. A comand file mapsim.cmd is included in the MPI version which can be used to run mapsim on an IBM SP machine.