Galaxy evolution explorer ultraviolet color-magnitude relations and evidence of recent star formation in early-type galaxies
Author
Yi, S.K.
Yoon, S.-J.
Lee, Y.-W.
Ree, C.H.
Sohn, Y.-J.
Rey, S.-C.
Rhee, J.
Byun, Y.-I.
Kim, S.-W.
Kaviraj, S.
Deharveng, J.-M.
Boselli, A.
Donas, J.
Malina, R.
Milliard, B.
Rich, R.M.
Salim, S.
Friedman, P.G.
Martin, D.C.
Morrissey, P.
Small, T.
Barlow, T.
Forster, K.
Wyder, T.K.
Lee, J.-W.
Bianchi, L.
Heckman, T.M.
Szalay, A.S.
Jee, M.J.
Jelinsky, P.
Siegmund, O.
Welsh, B.
Madore, B.F.
Neff, S.
Schiminovich, D.
Attention
2299/11924
Abstract
We have used the Galaxy Evolution Explorer UV photometric data to construct a first near-UV (NUV) color-magnitude relation (CMR) for the galaxies preclassified as early-type by Sloan Digital Sky Survey studies. The NUV CMR is a powerful tool for tracking the recent star formation history in early-type galaxies, owing to its high sensitivity to the presence of young stellar populations. Our NUV CMR for UV-weak galaxies shows a well-defined slope and thus will be useful for interpreting the rest-frame NUV data of distant galaxies and studying their star formation history. Compared to optical CMRs, the NUV CMR shows a substantially larger scatter, which we interpret as evidence of recent star formation activities. Roughly 15% of the recent epoch (z <0.13) bright [M(r) <-22] early-type galaxies show a sign of recent ≤1 Gyr) star formation at the 1%-2% level (lower limit) in mass compared to the total stellar mass. This implies that low-level residual star formation was common during the last few billion years even in bright early-type galaxies.