VizieR Online Data Catalog: SED of K+A galaxies from UV to mid-IR (Melnick+, 2013)

In this framework, the class of objects known as "K+A galaxies" is particularly interesting. These appear to be galaxies whose spectrum shows signs of a recent (within 0.2-2Gyr) episode of star formation, producing a strong Balmer series due to A stars, superposed over an old stellar population (dominated by K giants) typical of spheroids and early-type spirals. Nevertheless, there is no strong [OII] or Half emission indicating that star formation is currently not taking place. In many cases, the starburst appears to have comprised a significant fraction (20-60%) of the galaxy mass. K+A galaxies therefore are observed in a short-lived phase as they transit from the blue cloud to the red sequence and thus provide the opportunity to obtain unique insights into the processes leading to the morphological and spectrophotometric transformation of galaxies.

We used a sample of 811 K+A galaxies selected from the SDSS as described by Nielsen et al. (2012ApJ...761L..16N). This is an expansion of the K+A sample used by Goto (2007MNRAS.381..187G) and drawn from the seventh data release of the SDSS (Abazajian et al. 2009ApJS..182..543A). Briefly, only objects classified as galaxies with a spectroscopic S/N>10 per pixel are considered. The selection criteria of K+A galaxies are equivalent widths of Hα>-3.0Å, Hδ>5.0Å and [OII]>-2.5Å where emission lines are negative. Galaxies with redshift 0.35<z<0.37 have been excluded due to contamination by the 5577Å atmospheric feature.

(2 data files).