Kohonen selected E+A galaxies from SDSS DR7

In the colour-mass diagram, the PSB sample is clearly concentrated towards the region between the red and the blue cloud, in agreement with the idea that PSB galaxies represent the transitioning phase between actively and passively evolving galaxies. The relative frequency of distorted PSB galaxies is at least 57%, significantly higher than in a comparison sample.

The search for active galactic nuclei (AGN) based on conventional selection criteria in the radio and MIR results in a low AGN fraction of 2-3%. We confirm an MIR excess in the mean SED of the PSB galaxy sample that may indicate hidden AGNs, though other sources are also possible.