Smac is a map making utility for idealized observations.


This software package is currently developed by Klaus Dolag and and based on an initial version of Alessandro Gardini. It contains contribution by Bepi Tormen, Mauro Roncarelli, Elena Rasia, Matteo Maturi, Julius Donnert and Dunja Fabjan.

A description of the current implementation of the map making procedure can be found in Dolag et al. 2005.

Functionality for JobRunner

The returned fits maps contain the image in the first extension and the header gives some additional information about the parameters used for the map making, e.g. BOX_KPC contains the width of the image in units of kpc, BOX_PX holds the number of pixels and Z_KPC holds the integration length along the third dimension (in units of kpc).
The linear size of a pixel therefore is dL = BOX_KPC/BOX_PX and the area covert by a pixel is dA = (BOX_KPC/BOX_PX)^2 = 2.3245627e+45 cm^2 There is now additionally the keyword REDSHIFT indicating the redshift of the image as well as PSIZEKPC and PARCMIN indicating the pixel size in kpc and arc-min respectively.

For the JobRunner project, currently the full list of possible map making features is now available, but it has to be reminded that not all maps can be drawn from every simulations. Some of them require very special physics included. Following functionality will produce idealized observations and should be functional (click on the image to get the corresponding sample fits file):

Meaning of the parameters

Choose the units to specify the image, either arcmin or kpc. Recommended is to use kpc.

Give the size of the image. If kpc was selected as unit, useful values are of order of 1000. Note that the size is given in physical units, so be aware to choose accordingly smaller values at high redshift.

Same than IMG_XY_SIZE but describing length of the line of sight to integrate through the cluster. Use values similar to the cluster size, as the underlying simulations are limited in their proper resolved volume around the cluster (typically 3-5 R_200). Note that the value is also given in physical units, so be aware to choose accordingly smaller values at high redshift.

Number of pixels for the image. As the background process which on the fly is calculating the image is limited in execution time on the server, do not choose large values. Typically 128 should work with all simulations.

Position to center the image on, in code units. Use the aim button on the left to select a proper cluster you want to make the image from.

Select the axis along the projection should be performed.

Select the output type of the ideal observation you want to perform.

Select the units for the temperature maps, either K or keV.

Select a lower temperature of particles contribution to your observations. Can be used to exclude some of the cool cores in the simulations.

Specify the energy band for the x-ray surface brightness and the emission weighted temperature maps.

Functionality for Lightcones

The output for a light-cone has several data products, here an example of the geometry of a constructed light-cone:

Tracing the light-cone back in time, the according slice is taken from snapshots at that epoch. The blue dashed lines mark the redshift of each slice. The green area symbolize the slice taken from each snapshot. Every of this slices has different data products (as described below), where each file will have a prefix NAME corresponding to the cosmological model used and a number, corresponding to the snapshot number it was created from.

Here is a small idl program showing how to convert the coordinates from the simulation into positions within the image.


Contact Klaus Dolag ( in case of questions.