Search for dense molecular gas in QSO hosts
  We present the results of a recently conducted mm-experiment at the IRAM 30m telescope. We searched in two QSO hosts for the HCN(J=1-0) line emission tracing the dense regions of gas. Our goal is to probe the HCN-CO line ratio in QSO hosts for the first time and to compare the results with recent findings of quiescent galaxies. These findings indicate a strong correlation between the star formation efficiency and the HCN-CO line ratio over several orders of magnitudes in infrared luminosities. 
J.-U. Pott, A. Eckart, M. Krips, L. Tacconi-Garman, and E. Lindt