2012/05/30 by L. Cortese
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Optics #Physics #Sky #Star (game theory) #Star formation #Stars #Stellar mass #Stellar, planetary, and galactic studies #Ultraviolet #astro-ph.CO
paper · pdf · doi:10.1051/0004-6361/201219443
4 pages, 2 figures. Accepted for publication on A&A (Research Note)
arxiv created 2012/05/30 · openalex publication_date 2012/07/01 · arxiv updated 2015/06/05 · openalex created_date 2022/09/17 · openalex updated_date 2026/08/05
We used GALEX ultraviolet and WISE 22 μm observations to investigate the current star formation activity of the optically red spirals recently identified as part of the Galaxy Zoo project. These galaxies were accurately selected from the Sloan Digital Sky Survey as pure discs with low or no current star formation activity, representing one of the best optically selected samples of candidate passive spirals. However, we show that these galaxies are not only still forming stars at a significant rate (≳1 M⊙ yr-1) but, more importantly, their star formation activity is not different from that of normal star-forming discs of the same stellar mass (M∗ ≳ 1010.2 M⊙). Indeed, these systems lie on the UV-optical blue sequence, even without any corrections for internal dust attenuation, and they follow the same specific star formation rate vs. stellar mass relation of star-forming galaxies. Our findings clearly show that at high stellar masses, optical colours do not allow to distinguish between actively star-forming and truly quiescent systems.