Observational evidence of quasar feedback quenching star formation at high redshift M. Cano-Díaz, R. Maiolino, A. Marconi, H. Netzer, O. Shemmer and G. Cresci A&A, 537 (2012) L8 Published online: 17 January 2012 DOI: 10.1051/0004-6361/201118358