The GALEX/S4G Surface Brightness and Color Profiles Catalog. I. Surface Photometry and Color Gradients of Galaxies

Alexandre Y.K. Bouquin, Armando Gil De Paz, Juan Carlos Muñoz-Mateos, Samuel Boissier, Kartik Sheth, Dennis Zaritsky, Reynier F. Peletier, Johan H. Knapen, Jesús Gallego

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

We present new spatially resolved surface photometry in the far-ultraviolet (FUV) and near-ultraviolet (NUV) from images obtained by the Galaxy Evolution Explorer (GALEX) and IRAC1 (3.6 μm) photometry from the Spitzer Survey of Stellar Structure in Galaxies (S4G). We analyze the radial surface brightness profiles μ FUV, μ NUV, and μ [3.6], as well as the radial profiles of (FUV - NUV), (NUV - [3.6]), and (FUV - [3.6]) colors in 1931 nearby galaxies (z < 0.01). The analysis of the 3.6 μm surface brightness profiles also allows us to separate the bulge and disk components in a quasi-automatic way and to compare their light and color distribution with those predicted by the chemo-spectrophotometric models for the evolution of galaxy disks of Boissier & Prantzos. The exponential disk component is best isolated by setting an inner radial cutoff and an upper surface brightness limit in stellar mass surface density. The best-fitting models to the measured scale length and central surface brightness values yield distributions of spin and circular velocity within a factor of two of those obtained via direct kinematic measurements. We find that at a surface brightness fainter than μ [3.6] = 20.89 mag arcsec-2, or below 3 × 108 M o kpc-2 in stellar mass surface density, the average specific star formation rate (sSFR) for star-forming and quiescent galaxies remains relatively flat with radius. However, a large fraction of GALEX Green Valley galaxies show a radial decrease in sSFR. This behavior suggests that an outside-in damping mechanism, possibly related to environmental effects, could be testimony of an early evolution of galaxies from the blue sequence of star-forming galaxies toward the red sequence of quiescent galaxies.

Original languageEnglish (US)
Article number18
JournalAstrophysical Journal, Supplement Series
Volume234
Issue number2
DOIs
StatePublished - Feb 2018

Keywords

  • catalogs
  • galaxies: photometry
  • galaxies: star formation
  • infrared: galaxies
  • ultraviolet: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Bouquin, A. Y. K., Gil De Paz, A., Muñoz-Mateos, J. C., Boissier, S., Sheth, K., Zaritsky, D., Peletier, R. F., Knapen, J. H., & Gallego, J. (2018). The GALEX/S4G Surface Brightness and Color Profiles Catalog. I. Surface Photometry and Color Gradients of Galaxies. Astrophysical Journal, Supplement Series, 234(2), [18]. https://doi.org/10.3847/1538-4365/aaa384