Galaxy And Mass Assembly (GAMA): Structural Investigation of Galaxies via Model Analysis

Lee S. Kelvin*, Simon P. Driver, Aaron S. G. Robotham, David T. Hill, Mehmet Alpaslan, Ivan K. Baldry, Steven P. Bamford, Joss Bland-Hawthorn, Sarah Brough, Alister W. Graham, Boris Haeussler, Andrew M. Hopkins, Jochen Liske, Jon Loveday, Peder Norberg, Steven Phillipps, Cristina C. Popescu, Matthew Prescott, Edward N. Taylor, Richard J. Tuffs

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

205 Citations (Scopus)

Abstract

We present single-Sersic two-dimensional (2D) model fits to 167 600 galaxies modelled independently in the ugrizYJHK bandpasses using reprocessed Sloan Digital Sky Survey Data Release Seven (SDSS DR7) and UKIRT Infrared Deep Sky Survey Large Area Survey imaging data available from the Galaxy And Mass Assembly (GAMA) data base. In order to facilitate this study we developed Structural Investigation of Galaxies via Model Analysis (SIGMA), an R wrapper around several contemporary astronomy software packages including SOURCE EXTRACTOR, PSF EXTRACTOR and GALFIT 3. SIGMA produces realistic 2D model fits to galaxies, employing automatic adaptive background subtraction and empirical point spread function measurements on the fly for each galaxy in GAMA. Using these results, we define a common coverage area across the three GAMA regions containing 138 269 galaxies. We provide Sersic magnitudes truncated at 10r(e) which show good agreement with SDSS Petrosian and GAMA photometry for low Sersic index systems (n <4), and much improved photometry for high Sersic index systems (n > 4), recovering as much as Delta m = 0.5 mag in the r band. We employ a K-band Sersic index/u - r colour relation to delineate the massive (n > similar to 2) early-type galaxies (ETGs) from the late-type galaxies (LTGs). The mean Sersic index of these ETGs shows a smooth variation with wavelength, increasing by 30 per cent from g through K. LTGs exhibit a more extreme change in Sersic index, increasing by 52 per cent across the same range. In addition, ETGs and LTGs exhibit a 38 and 25 per cent decrease, respectively, in half-light radius from g through K. These trends are shown to arise due to the effects of dust attenuation and stellar population/metallicity gradients within galaxy populations.

Original languageEnglish
Pages (from-to)1007-1039
Number of pages33
JournalMonthly Notices of the Royal Astronomical Society
Volume421
Issue number2
DOIs
Publication statusPublished - Apr 2012

Keywords

  • astronomical data bases: miscellaneous
  • catalogues
  • galaxies: fundamental parameters
  • galaxies: structure
  • SPECTRAL ENERGY-DISTRIBUTION
  • DIGITAL SKY SURVEY
  • LAMBDA-CDM UNIVERSE
  • EARLY DATA RELEASE
  • WIDE-FIELD CAMERA
  • SPIRAL GALAXIES
  • DISK GALAXIES
  • STAR-FORMATION
  • STELLAR MASS
  • ELLIPTIC GALAXIES

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