Publication: Group-finding with Photometric Redshifts: The Photo-z Probability Peaks Algorithm
All || By Area || By Year| Title | Group-finding with Photometric Redshifts: The Photo-z Probability Peaks Algorithm | Authors/Editors* | Gillis, Bryan, Hudson, Micheal J. |
|---|---|
| Where published* | Monthly Notices of the Royal Astronomical Society |
| How published* | Journal |
| Year* | 2011 |
| Volume | 410 |
| Number | |
| Pages | 13- |
| Publisher | Wiley |
| Keywords | |
| Link | http://dx.doi.org/10.1111/j.1365-2966.2010.17415.x |
| Abstract |
We present a galaxy group-finding algorithm, the Photo-z Probability Peaks (P3) algorithm, optimized for locating small galaxy groups using photometric redshift data by searching for peaks in the signal-to-noise of the local overdensity of galaxies in a three-dimensional grid. This method is an improvement over similar two-dimensional matched-filter methods in reducing background contamination through the use of red-shift information, allowing it to accurately detect groups at lower richness. We present the results of tests of our algorithm on galaxy catalogues from the Millennium Simulation. Using a minimum S/N of 3 for detected groups, a group aperture size of 0.25 Mpc/h, and assuming photometric redshift accuracy of sigma_z = 0.05 it attains a purity of 84% and detects â¼ 295 groups/deg.2 with an average group richness of 8.6 members. Assuming photometric redshift accuracy of sigma_z = 0.02, it attains a purity of 97% and detects â¼ 143 groups/deg.2 with an average group richness of 12.5 members. We also test our algorithm on data available for the COSMOS field and the presently-available fields from the CFHTLS-Wide survey, presenting preliminary results of this analysis. |
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