WVT Binning

by Steven Diehl & Tom Statler

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About WVT Binning

Cassiopeia A

WVT Binning is a spatially adaptive 2-dimensional binning algorithm, designed to bin sparse X-ray data. It can handle background subtracted, exposure corrected data to produce intensity images, hardness ratio maps, or temperature maps. We have already successfully applied WVT Binning to bin X-ray data of galaxy clusters, individual galaxies, and supernova remnants, as well as integral field spectroscopy from SAURON. Details about WVT Binning are described in "Adaptive Binning of X-ray Data with Weighted Voronoi Tesselations" (Diehl & Statler 2006). The algorithm is an extension of Cappellari & Copin's (2003) Voronoi binning code.

The algorithm uses Weighted Voronoi Tesselations (WVT) to produce a very compact binning structure with a constant S/N per bin. The bin size adjusts to the required resolution in single-pixel steps, which minimizes the scatter around the target S/N. The code is very versatile and can in principle be applied to any type of data. The user manual contains instructions on how to apply the WVT binning code to X-ray data and how to extend the algorithm to other problems.


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Examples

Intensity Maps/Gas Maps

Intensity Map NGC 5044Chandra surface brightness map for the hot gas in NGC5044, binned to a S/N of 4

Temperature Maps

Temperature Map NGC 4636Chandra temperature map for NGC4636, binned to a S/N of 30, i.e. 900 counts/bin

Hardness Ratio Maps

Color Map PerseusChandra color map for the core of the Perseus cluster (25ksec exposure), binned to a S/N of 10

Integral Field Spectroscopy

IFS NGC 2273SAURON IFS data for NGC2273, binned to a S/N of 50
All of these examples are further described in out WVT binning paper.

Copyright and Citing References

WVT Binning is a generalization of Cappellari & Copin's Voronoi binning algorithm. If you find this algorithm useful for you analysis, we ask you to cite both papers, e.g. "We made use of the WVT binning algorithm by Diehl & Statler (2006), which is a generalization of Cappellari & Copin's (2003) Voronoi binning algorithm."

WVT Binning is provided free of charge, and without any warranty. For more detailed copyright information, please refer to the header of WVT_BINNING.PRO


Contact Information

If you have any questions about the functionality of the algorithm, please send an email to diehl@helios.phy.ohiou.edu We also appreciate any bug reports and/or suggestions for improvement of the code. Feel free to contact me if you have trouble to apply WVT binning to other types of data.


Modification History