PAH emission and star formation in the host of the z ∼ 2.56 cloverleaf QSO

D. Lutz*, E. Sturm, L. J. Tacconi, E. Valiante, M. Schweitzer, H. Netzer, R. Maiolino, P. Andreani, O. Shemmer, S. Veilleux

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


We report the first detection of the 6.2 and 7.7 μm infrared polycyclic aromatic hydrocarbon (PAH) emission features in the spectrum of a high-redshift QSO, from the Spitzer IRS spectrum of the Cloverleaf lensed QSO (H1413 +117, z ∼ 2.56). The ratio of PAH features and rest-frame far-infrared emission is the same as in lower luminosity star-forming ULIRGs and in local PG QSOs, supporting a predominantly starburst nature of the Cloverleaf s huge far-infrared luminosity (5.4 × 1012 L, corrected for lensing). The Cloverleaf's period of dominant QSO activity (L Bol ∼ 7 × 1013 L) is coincident with an intense (star formation rate ∼ 1000 M yr -1) and short (gas exhaustion time ∼ 3 × 107 yr) star-forming event.

Original languageEnglish
Pages (from-to)L25-L28
JournalAstrophysical Journal
Issue number1 II
StatePublished - 20 May 2007


  • Galaxies: active
  • Galaxies: starburst
  • Infrared: galaxies


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