Exploring the spectroscopic properties of relic radiogalaxies A. Capetti, A. Robinson, R. D. Baldi, S. Buttiglione, D. J. Axon, A. Celotti and M. Chiaberge A&A, 551 (2013) A55 Published online: 21 February 2013 DOI: 10.1051/0004-6361/201220662