تقرير
The GALEX/S4G UV-IR color-color diagram: Catching spiral galaxies away from the Blue Sequence
| العنوان: | The GALEX/S4G UV-IR color-color diagram: Catching spiral galaxies away from the Blue Sequence |
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| المؤلفون: | Bouquin, Alexandre Y. K., de Paz, Armando Gil, Boissier, Samuel, Muñoz-Mateos, Juan-Carlos, Sheth, Kartik, Zaritsky, Dennis, Laine, Jarkko, Gallego, Jesús, Peletier, Reynier F., Röck, Benjamin R., Knapen, Johan H. |
| سنة النشر: | 2015 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies |
| الوصف: | We obtained GALEX FUV, NUV, and Spitzer/IRAC 3.6$\mu$m 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 ($\tau$) and a degeneracy between $\tau$ 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 $\rm{M}_{[3.6]}$), since both massive ($M_{\star} > 10^{11} M_{\odot}$) blue and red sequence galaxies are identified. The type that is proportionally more often found in the GGV are 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 timescale of $10^{8}$years. Comment: 7 pages, 4 figures, 1 table. Accepted for publication in ApJL |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1088/2041-8205/800/1/L19 |
| URL الوصول: | http://arxiv.org/abs/1501.06588 |
| رقم الأكسشن: | edsarx.1501.06588 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1088/2041-8205/800/1/L19 |
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