UV-IR color profiles of the outer regions of 2K nearby S$^{4}$G galaxies [GA]

http://arxiv.org/abs/1606.00275


We present our new, spatially-resolved, photometry in FUV and NUV from images obtained by GALEX, and IRAC1 (3.6 $\mu$m) photometry obtained by the Spitzer Space Telescope. We analyzed the surface brightness profiles $\mu_{\rm{FUV}}$, $\mu_{\rm{NUV}}$, $\mu_{[3.6]}$, as well as the radial evolution of the (FUV-NUV), (FUV – [3.6]), and (NUV – [3.6]) colors in the Spitzer Survey of Stellar Structures in Galaxies (S$^{4}$G) galaxies (d$<$40 Mpc) sample. We defined the GALEX Blue Sequence (GBS) and GALEX Red Sequence (GBR) from the (FUV – NUV) versus (NUV – [3.6]) color-color diagram, populated by late-type star forming galaxies and quiescent early-type galaxies respectively. While most disk becomes radially bluer for GBS galaxies, and stay constant for GRS galaxies, a large fraction ($>$50%) of intermediary GALEX Green Valley (GGV) galaxies’ outer disks are becoming redder. An outside-in quenching mechanism such as environmentally-related mechanisms such as starvation or ram-pressure-stripping could explain our results.

Read this paper on arXiv…

A. Bouquin and A. Paz
Thu, 2 Jun 16
45/60

Comments: 3 pages 1 figure, to be published in the Proceedings of IAU Symposium 321, “Formation and evolution of galaxy outskirts”, Eds. A. Gil de Paz, J. C. Lee & J. H. Knapen, Cambridge University Press, Cambridge