Identification of structures from galaxy counts : use of the wavelet transform.
Abstract
We describe in this paper a method for the automated detection and characterization of all the structural components in a catalogue of galaxies. The local analysis of the distribution is performed using the wavelet transform, a new mathematical technique which achieves a complete insight of the structures scale by scale and allows one to look at the scaling properties. Statistically significant clusters, and also for the first time voids, can be detected at each scale without the choice of artificial parameters. This technique is applied to a peculiar 2D objective catalogue of 7000 galaxies in a 6^deg^ x 6^deg^ field. Comparisons with well-known clusters and a previous method based on smoothed surface density enhancements are performed. The wavelet transform is shown to be very powerful, and serious information on the splitting, the fractal structure of the galaxy distribution and the global topology is anticipated. Moreover very promising applications to the detection of substructures in clusters are expected.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1990
- Bibcode:
- 1990A&A...227..301S
- Keywords:
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- Cosmology;
- Galactic Structure;
- Universe;
- Astronomical Catalogs;
- Density Distribution;
- Fourier Transformation;
- Galactic Clusters;
- Astronomy