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E. J. Hooper, B. J. Wilkes (CfA), K. K. McLeod (Wellesley), M. S. Elvis (CfA), D. H. Hughes (INAOE), C. D. Impey (Steward Obs.), J. K. Kuraszkiewicz (CfA), C. J. Lonsdale (IPAC), M. A. Malkan (UCLA), J. C. McDowell (CfA)
Infrared and sub-mm data for high redshift AGN probe the energetics of the active nucleus and star formation in the early universe. We discuss the spectral energy distributions (SEDs) and star-formation rates of distant quasars, centered on 3 - 200 \micron ISOPHOT photometry and SCUBA observations for a high redshift subsample (extending to z = 4.7) of the NASA/ISO Key Project on AGN.
Upper limits to the star-formation rate are often calculated by assuming that the cool dust emission in thermally dominated sources is predominantly pumped by the stars rather than the AGN, which yields values of thousands of M\odot\; {\rm yr}-1 for some high z quasars. An additional constraint on the star-formation rate, not subject to this assumption, is available from the total dust mass and the time interval from the presumed epoch of initial star formation (z = 10 - 15) to the epoch when the quasar emitted the observed light. This yields an average star-formation rate in the highest redshift ISO sample quasars of a few hundred M\odot\; {\rm yr}-1 for a 1% dust production efficiency, indicating vigorous star formation but still an order of magnitude below the rate inferred by assuming all of the dust is heated by stars. Either these sources are observed during an intense short duration burst 10\times the average star-formation rate, or reprocessed AGN emission dominates the rest-frame far-infrared emission.
We gratefully acknowledge the financial support of NASA grant NAG5-8847.
The author(s) of this abstract have provided an email address for comments about the abstract: ehooper@cfa.harvard.edu