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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents



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ID: 661093.0, MPI für Astronomie / Publikationen_mpia
GALAPAGOS: from pixels to parameters
Authors:Barden, Marco; Häuߟler, Boris; Peng, Chien Y.; McIntosh, Daniel H.; Guo, Yicheng
Date of Publication (YYYY-MM-DD):2012
Title of Journal:Monthly Notices of the Royal Astronomical Society
Journal Abbrev.:MNRAS
Volume:422
Issue / Number:1
Start Page:449
End Page:468
Review Status:not specified
Audience:Not Specified
Abstract / Description:To automate source detection, two-dimensional light profile Sérsic modelling and catalogue compilation in large survey applications, we introduce a new code Galaxy Analysis over Large Areas: Parameter Assessment by GALFITting Objects from SEXTRACTOR (GALAPAGOS). Based on a single set-up, GALAPAGOS can process a complete set of survey images. It detects sources in the data, estimates a local sky background, cuts postage stamp images for all sources, prepares object masks, performs Sérsic fitting including neighbours and compiles all objects in a final output catalogue. For the initial source detection, GALAPAGOS applies SEXTRACTOR, while GALFIT is incorporated for modelling Sérsic profiles. It measures the background sky involved in the Sérsic fitting by means of a flux growth curve. GALAPAGOS determines postage stamp sizes based on SEXTRACTOR shape parameters. In order to obtain precise model parameters, GALAPAGOS incorporates a complex sorting mechanism and makes use of modern CPU's multiplexing capabilities. It combines SEXTRACTOR and GALFIT data in a single output table. When incorporating information from overlapping tiles, GALAPAGOS automatically removes multiple entries from identical sources. GALAPAGOS is programmed in the Interactive Data Language (IDL). We test the stability and the ability to properly recover structural parameters extensively with artificial image simulations. Moreover, we apply GALAPAGOS successfully to the STAGES data set. For one-orbit Hubble Space Telescope data, a single 2.2-GHz CPU processes about 1000 primary sources per 24 h. Note that GALAPAGOS results depend critically on the user-defined parameter set-up. This paper provides useful guidelines to help the user make sensible choices.
Free Keywords:methods: data analysis; surveys; galaxies: statistics; galaxies: structure
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://cdsads.u-strasbg.fr/abs/2012MNRAS.422..449B [ID No:1]
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