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Title: Probability friends-of-friends (PFOF) group finder: Performance study and observational data applications on photometric surveys

In tandem with observational data sets, we utilize realistic mock catalogs, based on a semi-analytic galaxy formation model, constructed specifically for Pan-STARRS1 Medium Deep Surveys to assess the performance of the Probability Friends-of-Friends (PFOF) group finder, and aim to develop a grouping optimization method applicable to surveys like Pan-STARRS1. Producing mock PFOF group catalogs under a variety of photometric redshift accuracies (σ{sub Δz/(1+z{sub s)}}), we find that catalog purities and completenesses from 'good' (σ{sub Δz/(1+z{sub s)}}∼ 0.01) to 'poor' (σ{sub Δz/(1+z{sub s)}}∼ 0.07) photo-zs gradually degrade from 77% and 70% to 52% and 47%, respectively. A 'subset optimization' approach is developed by using spectroscopic-redshift group data from the target field to train the group finder for application to that field and demonstrated using zCOSMOS groups for PFOF searches within PS1 Medium Deep Field04 (PS1MD04) and DEEP2 EGS groups in PS1MD07. With four data sets spanning the photo-z accuracy range from 0.01 to 0.06, we find purities and completenesses agree with their mock analogs. Further tests are performed via matches to X-ray clusters. We find PFOF groups match ∼85% of X-ray clusters identified in COSMOS and PS1MD04, lending additional support to the reliability of the detection algorithm. In the end, wemore » demonstrate, by separating red and blue group galaxies in the EGS and PS1MD07 group catalogs, that the algorithm is not biased with respect to specifically recovering galaxies by color. The analyses suggest the PFOF algorithm shows great promise as a reliable group finder for photometric galaxy surveys of varying depth and coverage.« less
Authors:
;  [1] ; ; ; ; ;  [2] ;  [3] ; ;  [4] ;  [5] ;  [6] ; ;  [7]
  1. Department of Physics, National Taiwan University, 106, Taipei, Taiwan (China)
  2. Institute of Astronomy and Astrophysics, Academia Sinica, 106, Taipei, Taiwan (China)
  3. Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)
  4. Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
  5. National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)
  6. Department of Astronomy and Astrophysics, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile)
  7. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
Publication Date:
OSTI Identifier:
22356628
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 788; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; ALGORITHMS; CATALOGS; COLOR; DATA ANALYSIS; DETECTION; GALAXIES; GALAXY CLUSTERS; IMPURITIES; OPTIMIZATION; PROBABILITY; RED SHIFT; RELIABILITY; X RADIATION