SIMBAD references

2015ApJ...800L..19B - Astrophys. J., 800, L19 (2015/February-2)

The GALEX/S4G UV-IR color-color diagram: catching spiral galaxies away from the blue sequence.

BOUQUIN A.Y.K., GIL DE PAZ A., BOISSIER S., MUNOZ-MATEOS J.-C., SHETH K., ZARITSKY D., LAINE J., GALLEGO J., PELETIER R.F., ROCK B.R. and KNAPEN J.H.

Abstract (from CDS):

We obtained GALEX FUV, NUV, and Spitzer/IRAC 3.6 µm photometry for > 2000 galaxies, available for 90% of the S4G sample. We find a very tight GALEX blue sequence (GBS) in the (FUV-NUV) versus (NUV-[3.6]) color-color diagram, which is populated by irregular and spiral galaxies, and is mainly driven by changes in the formation timescale (τ) and a degeneracy between τ and dust reddening. The tightness of the GBS provides an unprecedented way of identifying star-forming galaxies and objects that are just evolving to (or from) what we call the GALEX green valley (GGV). At the red end of the GBS, at (NUV-[3.6]) > 5, we find a wider GALEX red sequence (GRS) mostly populated by E/S0 galaxies that has a perpendicular slope to that of the GBS and of the optical red sequence. We find no such dichotomy in terms of stellar mass (measured by M[3,6]) since both massive (M* > 1011M) blue- and red-sequence galaxies are identified. The type that is proportionally more often found in the GGV is the S0-Sa's, and most of these are located in high-density environments. We discuss evolutionary models of galaxies that show a rapid transition from the blue to the red sequence on a timescale of 108 yr.

Abstract Copyright:

Journal keyword(s): galaxies: evolution - galaxies: photometry - galaxies: star formation

Simbad objects: 6

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2019.10.23-18:50:14

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